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< ul class = "crumbs" > < li > < a href = "../index.html" > Home< / a > < / li > < li > < a href = "../services.html" > Services< / a > < / li > < li > < a href = "index.html" > syntax< / a > < / li > < li > < a href = "index.html#2" > Chapter 2: The Parse Tree< / a > < / li > < li > < b > Syntax Trees< / b > < / li > < / ul > < / div >
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< p class = "purpose" > To parse trees which decompose the meaning of excerpts of text, and which allow annotations to be made at each node.< / p >
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< ul class = "toc" > < li > < a href = "2-st.html#SP1" > § 1. Optional headings tree< / a > < / li > < li > < a href = "2-st.html#SP2" > § 2. Syntax trees< / a > < / li > < li > < a href = "2-st.html#SP3" > § 3. Buds and grafts< / a > < / li > < li > < a href = "2-st.html#SP9" > § 9. Where we currently are in the text< / a > < / li > < li > < a href = "2-st.html#SP10" > § 10. General traversals< / a > < / li > < li > < a href = "2-st.html#SP19" > § 19. Cautious traverses< / a > < / li > < li > < a href = "2-st.html#SP20" > § 20. Toggling log output< / a > < / li > < li > < a href = "2-st.html#SP21" > § 21. Ambiguity subtrees< / a > < / li > < / ul > < hr class = "tocbar" >
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< p class = "commentary firstcommentary" > < a id = "SP1" class = "paragraph-anchor" > < / a > < b > § 1. Optional headings tree. < / b > Within < a href = "../inform7/index.html" class = "internal" > inform7< / a > and < a href = "../inbuild/index.html" class = "internal" > inbuild< / a > , the code in this section is augmented by
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< a href = "../supervisor-module/6-hdn.html" class = "internal" > Headings (in supervisor)< / a > , which gives every syntax tree an associated tree of
source headings; but as far as < a href = "index.html" class = "internal" > syntax< / a > is concerned, that's all an optional
extra.
< / p >
< p class = "commentary" > Code using < a href = "index.html" class = "internal" > syntax< / a > in this way must define < span class = "extract" > < span class = "extract-syntax" > HEADING_TREE_SYNTAX_TYPE< / span > < / span > as the
class of object to which our < span class = "extract" > < span class = "extract-syntax" > headings< / span > < / span > field will point, and callback functions
< span class = "extract" > < span class = "extract-syntax" > NEW_HEADING_TREE_SYNTAX_CALLBACK< / span > < / span > and < span class = "extract" > < span class = "extract-syntax" > NEW_HEADING_SYNTAX_CALLBACK< / span > < / span > to
initialise and add to it.
< / p >
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< pre class = "definitions code-font" > < span class = "definition-keyword" > default< / span > < span class = "constant-syntax" > HEADING_TREE_SYNTAX_TYPE< / span > < span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > < / span > < span class = "comment-syntax" > in which case, never used< / span >
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< / pre >
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< p class = "commentary firstcommentary" > < a id = "SP2" class = "paragraph-anchor" > < / a > < b > § 2. Syntax trees. < / b > Each < a href = "2-st.html#SP2" class = "internal" > parse_node_tree< / a > object represents a different syntax tree; typically
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the entire source text being compiled by < a href = "../inform7/index.html" class = "internal" > inform7< / a > , including any extensions
it includes, will form a single < a href = "2-st.html#SP2" class = "internal" > parse_node_tree< / a > .
< / p >
< pre class = "definitions code-font" > < span class = "definition-keyword" > define< / span > < span class = "constant-syntax" > MAX_BUD_STACK_SIZE< / span > < span class = "plain-syntax" > < / span > < span class = "constant-syntax" > 100< / span > < span class = "plain-syntax" > < / span > < span class = "comment-syntax" > must be at least the number of heading levels plus 3< / span >
< / pre >
< pre class = "displayed-code all-displayed-code code-font" >
< span class = "reserved-syntax" > typedef< / span > < span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > struct< / span > < span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > {< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > struct< / span > < span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > root_node< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > bud_parent_sp< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > struct< / span > < span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > bud_parent_stack< / span > < span class = "plain-syntax" > [< / span > < span class = "constant-syntax" > MAX_BUD_STACK_SIZE< / span > < span class = "plain-syntax" > ];< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > struct< / span > < span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > last_sentence< / span > < span class = "plain-syntax" > ; < / span > < span class = "comment-syntax" > cached position in tree< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > allow_last_sentence_cacheing< / span > < span class = "plain-syntax" > ;< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > contains_dialogue< / span > < span class = "plain-syntax" > ;< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > trace_sentences< / span > < span class = "plain-syntax" > ;< / span >
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< span class = "plain-syntax" > < / span > < span class = "constant-syntax" > HEADING_TREE_SYNTAX_TYPE< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > headings< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > CLASS_DEFINITION< / span >
< span class = "plain-syntax" > } < / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > ;< / span >
< span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > *< / span > < span class = "function-syntax" > SyntaxTree::new< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > ) {< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > CREATE< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > );< / span >
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< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > root_node< / span > < span class = "plain-syntax" > = < / span > < a href = "2-pn.html#SP2" class = "function-link" > < span class = "function-syntax" > Node::new< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "constant-syntax" > ROOT_NT< / span > < span class = "plain-syntax" > );< / span >
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< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > bud_parent_sp< / span > < span class = "plain-syntax" > = < / span > < span class = "constant-syntax" > 0< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > last_sentence< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > NULL< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > allow_last_sentence_cacheing< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > FALSE< / span > < span class = "plain-syntax" > ;< / span >
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< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > trace_sentences< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > FALSE< / span > < span class = "plain-syntax" > ;< / span >
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< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > contains_dialogue< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > FALSE< / span > < span class = "plain-syntax" > ;< / span >
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< span class = "plain-syntax" > < / span > < a href = "2-st.html#SP3" class = "function-link" > < span class = "function-syntax" > SyntaxTree::push_bud< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > root_node< / span > < span class = "plain-syntax" > );< / span >
< span class = "plain-syntax" > #< / span > < span class = "identifier-syntax" > ifdef< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > NEW_HEADING_TREE_SYNTAX_CALLBACK< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > headings< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > NEW_HEADING_TREE_SYNTAX_CALLBACK< / span > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > );< / span >
< span class = "plain-syntax" > #< / span > < span class = "identifier-syntax" > endif< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< / pre >
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< ul class = "endnotetexts" > < li > The structure parse_node_tree is accessed in 2/tv, 3/snt and here.< / li > < / ul >
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< p class = "commentary firstcommentary" > < a id = "SP3" class = "paragraph-anchor" > < / a > < b > § 3. Buds and grafts. < / b > "Buds" are positions in the tree to which new sentence subtrees can be grafted:
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< / p >
< pre class = "displayed-code all-displayed-code code-font" >
< span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::push_bud< / span > < button class = "popup" onclick = "togglePopup('usagePopup1')" > < span class = "comment-syntax" > ?< / span > < span class = "popuptext" id = "usagePopup1" > Usage of < span class = "code-font" > < span class = "function-syntax" > SyntaxTree::push_bud< / span > < / span > :< br / > < a href = "2-st.html#SP2" > § 2< / a > , < a href = "2-st.html#SP4" > § 4< / a > < / span > < / button > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > , < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > to< / span > < span class = "plain-syntax" > ) {< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > l< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > bud_parent_sp< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "identifier-syntax" > bud_parent_sp< / span > < span class = "plain-syntax" > > = < / span > < span class = "constant-syntax" > MAX_BUD_STACK_SIZE< / span > < span class = "plain-syntax" > ) < / span > < span class = "identifier-syntax" > internal_error< / span > < span class = "plain-syntax" > (< / span > < span class = "string-syntax" > "bud stack overflow"< / span > < span class = "plain-syntax" > );< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > bud_parent_stack< / span > < span class = "plain-syntax" > [< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > bud_parent_sp< / span > < span class = "plain-syntax" > ++] = < / span > < span class = "identifier-syntax" > to< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > l< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::pop_bud< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > , < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > l< / span > < span class = "plain-syntax" > ) {< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > bud_parent_sp< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > l< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< / pre >
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< p class = "commentary firstcommentary" > < a id = "SP4" class = "paragraph-anchor" > < / a > < b > § 4. < / b > Sentences are grafted onto the bud position at the top of the stack.
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< / p >
< pre class = "displayed-code all-displayed-code code-font" >
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< span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::graft_sentence< / span > < button class = "popup" onclick = "togglePopup('usagePopup2')" > < span class = "comment-syntax" > ?< / span > < span class = "popuptext" id = "usagePopup2" > Usage of < span class = "code-font" > < span class = "function-syntax" > SyntaxTree::graft_sentence< / span > < / span > :< br / > Sentences - < a href = "3-snt.html#SP6_1" > § 6.1< / a > , < a href = "3-snt.html#SP6_6" > § 6.6< / a > , < a href = "3-snt.html#SP6_9_3" > § 6.9.3< / a > , < a href = "3-snt.html#SP6_9_9_1" > § 6.9.9.1< / a > , < a href = "3-snt.html#SP6_9_9_2" > § 6.9.9.2< / a > , < a href = "3-snt.html#SP6_9_9_3" > § 6.9.9.3< / a > , < a href = "3-snt.html#SP6_9_9_3_1_1" > § 6.9.9.3.1.1< / a > , < a href = "3-snt.html#SP6_9_9_3_3" > § 6.9.9.3.3< / a > < / span > < / button > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > , < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > new< / span > < span class = "plain-syntax" > ) {< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "identifier-syntax" > bud_parent_sp< / span > < span class = "plain-syntax" > == < / span > < span class = "constant-syntax" > 0< / span > < span class = "plain-syntax" > ) < / span > < span class = "identifier-syntax" > internal_error< / span > < span class = "plain-syntax" > (< / span > < span class = "string-syntax" > "no attachment point"< / span > < span class = "plain-syntax" > );< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-pn.html#SP5" class = "function-link" > < span class = "function-syntax" > Node::get_type< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > new< / span > < span class = "plain-syntax" > ) == < / span > < span class = "constant-syntax" > HEADING_NT< / span > < span class = "plain-syntax" > ) < / span > < span class = "named-paragraph-container code-font" > < a href = "2-st.html#SP4_1" class = "named-paragraph-link" > < span class = "named-paragraph" > Adjust bud point for a heading< / span > < span class = "named-paragraph-number" > 4.1< / span > < / a > < / span > < span class = "plain-syntax" > ;< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > sentence_attachment_point< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > bud_parent_stack< / span > < span class = "plain-syntax" > [< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > bud_parent_sp< / span > < span class = "plain-syntax" > -1];< / span >
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< span class = "plain-syntax" > < / span > < a href = "2-st.html#SP6" class = "function-link" > < span class = "function-syntax" > SyntaxTree::graft< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > new< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > sentence_attachment_point< / span > < span class = "plain-syntax" > );< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-pn.html#SP5" class = "function-link" > < span class = "function-syntax" > Node::get_type< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > new< / span > < span class = "plain-syntax" > ) == < / span > < span class = "constant-syntax" > HEADING_NT< / span > < span class = "plain-syntax" > ) < / span > < a href = "2-st.html#SP3" class = "function-link" > < span class = "function-syntax" > SyntaxTree::push_bud< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > new< / span > < span class = "plain-syntax" > );< / span >
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< span class = "plain-syntax" > }< / span >
< / pre >
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< p class = "commentary firstcommentary" > < a id = "SP4_1" class = "paragraph-anchor" > < / a > < b > § 4.1. < / b > When what's attached is a heading node, that changes the stack. The idea
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here is that sentences graft beneath the heading to which they belong. If the
current bud point is a heading called "Section 22", and then we reach the
heading sentence "Part 2", this no longer belongs under Section 22, and we
pop the bud stack until we're beneath a heading node superior to Parts.
< / p >
< p class = "commentary" > < span class = "named-paragraph-container code-font" > < span class = "named-paragraph-defn" > Adjust bud point for a heading< / span > < span class = "named-paragraph-number" > 4.1< / span > < / span > < span class = "comment-syntax" > =< / span >
< / p >
< pre class = "displayed-code all-displayed-code code-font" >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > heading_level< / span > < span class = "plain-syntax" > = < / span > < a href = "2-na.html#SP7" class = "function-link" > < span class = "function-syntax" > Annotations::read_int< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > new< / span > < span class = "plain-syntax" > , < / span > < span class = "constant-syntax" > heading_level_ANNOT< / span > < span class = "plain-syntax" > );< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > heading_level< / span > < span class = "plain-syntax" > > < / span > < span class = "constant-syntax" > 0< / span > < span class = "plain-syntax" > )< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > for< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > i< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > bud_parent_sp< / span > < span class = "plain-syntax" > -1; < / span > < span class = "identifier-syntax" > i< / span > < span class = "plain-syntax" > > =0; < / span > < span class = "identifier-syntax" > i< / span > < span class = "plain-syntax" > --) {< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > P< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > bud_parent_stack< / span > < span class = "plain-syntax" > [< / span > < span class = "identifier-syntax" > i< / span > < span class = "plain-syntax" > ];< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > ((< / span > < a href = "2-pn.html#SP5" class = "function-link" > < span class = "function-syntax" > Node::get_type< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > P< / span > < span class = "plain-syntax" > ) == < / span > < span class = "constant-syntax" > HEADING_NT< / span > < span class = "plain-syntax" > ) & & < / span >
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< span class = "plain-syntax" > (< / span > < a href = "2-na.html#SP7" class = "function-link" > < span class = "function-syntax" > Annotations::read_int< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > P< / span > < span class = "plain-syntax" > , < / span > < span class = "constant-syntax" > heading_level_ANNOT< / span > < span class = "plain-syntax" > ) > = < / span > < span class = "identifier-syntax" > heading_level< / span > < span class = "plain-syntax" > ))< / span >
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< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > bud_parent_sp< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > i< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< / pre >
< ul class = "endnotetexts" > < li > This code is used in < a href = "2-st.html#SP4" > § 4< / a > .< / li > < / ul >
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< p class = "commentary firstcommentary" > < a id = "SP5" class = "paragraph-anchor" > < / a > < b > § 5. < / b > Syntax trees for Inform source text have a tendency to be wide. If a source
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text is basically a list of 5000 sentences, then there may be a node with 5000
children, even though the maximum depth of the tree might be as low as 10.
< / p >
< p class = "commentary" > Because of that we must be wary of algorithms with quadratic running time in
the width of the tree, and we get around that with a cache. Certain "tree
surgery" operations, when the tree is being rearranged, would throw this,
so the optimisation should be enabled only when needed.
< / p >
< pre class = "displayed-code all-displayed-code code-font" >
< span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::enable_last_sentence_cache< / span > < button class = "popup" onclick = "togglePopup('usagePopup3')" > < span class = "comment-syntax" > ?< / span > < span class = "popuptext" id = "usagePopup3" > Usage of < span class = "code-font" > < span class = "function-syntax" > SyntaxTree::enable_last_sentence_cache< / span > < / span > :< br / > Sentences - < a href = "3-snt.html#SP5" > § 5< / a > < / span > < / button > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > ) {< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > last_sentence< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > NULL< / span > < span class = "plain-syntax" > ; < / span > < span class = "comment-syntax" > because this may have changed since last enabled< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > allow_last_sentence_cacheing< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > TRUE< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::disable_last_sentence_cache< / span > < button class = "popup" onclick = "togglePopup('usagePopup4')" > < span class = "comment-syntax" > ?< / span > < span class = "popuptext" id = "usagePopup4" > Usage of < span class = "code-font" > < span class = "function-syntax" > SyntaxTree::disable_last_sentence_cache< / span > < / span > :< br / > Sentences - < a href = "3-snt.html#SP5" > § 5< / a > < / span > < / button > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > ) {< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > allow_last_sentence_cacheing< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > FALSE< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< / pre >
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< p class = "commentary firstcommentary" > < a id = "SP6" class = "paragraph-anchor" > < / a > < b > § 6. < / b > The function < span class = "extract" > < span class = "extract-syntax" > SyntaxTree::graft< / span > < / span > is named by analogy with gardening, where the
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rootstock of one plant is joined to a scion (or cutting) of another, so that a
root chosen for strength can be combined with the fruits or blossom of the scion.
< / p >
< p class = "commentary" > < span class = "extract" > < span class = "extract-syntax" > SyntaxTree::graft< / span > < / span > returns the node for which < span class = "extract" > < span class = "extract-syntax" > scion< / span > < / span > is the immediate sibling,
that is, it returns the previously youngest child of the < span class = "extract" > < span class = "extract-syntax" > rootstock< / span > < / span > (or < span class = "extract" > < span class = "extract-syntax" > NULL< / span > < / span >
if it previously had no children).
< / p >
< pre class = "displayed-code all-displayed-code code-font" >
2022-09-14 13:03:49 +03:00
< span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "function-syntax" > SyntaxTree::graft< / span > < button class = "popup" onclick = "togglePopup('usagePopup5')" > < span class = "comment-syntax" > ?< / span > < span class = "popuptext" id = "usagePopup5" > Usage of < span class = "code-font" > < span class = "function-syntax" > SyntaxTree::graft< / span > < / span > :< br / > < a href = "2-st.html#SP4" > § 4< / a > < br / > Sentences - < a href = "3-snt.html#SP6_9_9_2" > § 6.9.9.2< / a > , < a href = "3-snt.html#SP6_9_9_3" > § 6.9.9.3< / a > , < a href = "3-snt.html#SP7_1" > § 7.1< / a > < / span > < / button > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > , < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > scion< / span > < span class = "plain-syntax" > , < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > rootstock< / span > < span class = "plain-syntax" > ) {< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > elder< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > NULL< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > scion< / span > < span class = "plain-syntax" > == < / span > < span class = "identifier-syntax" > NULL< / span > < span class = "plain-syntax" > ) < / span > < span class = "identifier-syntax" > internal_error< / span > < span class = "plain-syntax" > (< / span > < span class = "string-syntax" > "scion is null"< / span > < span class = "plain-syntax" > );< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > rootstock< / span > < span class = "plain-syntax" > == < / span > < span class = "identifier-syntax" > NULL< / span > < span class = "plain-syntax" > ) < / span > < span class = "identifier-syntax" > internal_error< / span > < span class = "plain-syntax" > (< / span > < span class = "string-syntax" > "rootstock is null"< / span > < span class = "plain-syntax" > );< / span >
< span class = "plain-syntax" > < / span > < span class = "comment-syntax" > is the new node to be the only child of the old?< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > rootstock< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > down< / span > < span class = "plain-syntax" > == < / span > < span class = "identifier-syntax" > NULL< / span > < span class = "plain-syntax" > ) { < / span > < span class = "identifier-syntax" > rootstock< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > down< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > scion< / span > < span class = "plain-syntax" > ; < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > NULL< / span > < span class = "plain-syntax" > ; }< / span >
< span class = "plain-syntax" > < / span > < span class = "comment-syntax" > can last sentence cacheing save us a long search through many children of root?< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > ((< / span > < span class = "identifier-syntax" > rootstock< / span > < span class = "plain-syntax" > == < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > root_node< / span > < span class = "plain-syntax" > ) & & (< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > allow_last_sentence_cacheing< / span > < span class = "plain-syntax" > )) {< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > last_sentence< / span > < span class = "plain-syntax" > ) {< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > elder< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > last_sentence< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > elder< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > next< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > scion< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > last_sentence< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > scion< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > elder< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< span class = "plain-syntax" > < / span > < span class = "comment-syntax" > we don't know who's the youngest child now, but we know who soon will be:< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "identifier-syntax" > last_sentence< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > scion< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< span class = "plain-syntax" > < / span > < span class = "comment-syntax" > find youngest child of rootstock...< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > for< / span > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > elder< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > rootstock< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > down< / span > < span class = "plain-syntax" > ; < / span > < span class = "identifier-syntax" > elder< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > next< / span > < span class = "plain-syntax" > ; < / span > < span class = "identifier-syntax" > elder< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > elder< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > next< / span > < span class = "plain-syntax" > ) ;< / span >
< span class = "plain-syntax" > < / span > < span class = "comment-syntax" > ...and make the new node its younger sibling< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > elder< / span > < span class = "plain-syntax" > -> < / span > < span class = "identifier-syntax" > next< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > scion< / span > < span class = "plain-syntax" > ; < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > elder< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< / pre >
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< p class = "commentary firstcommentary" > < a id = "SP7" class = "paragraph-anchor" > < / a > < b > § 7. < / b > No speed worries on the much smaller trees with alternative readings:
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< / p >
< pre class = "displayed-code all-displayed-code code-font" >
< span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "function-syntax" > SyntaxTree::graft_alternative< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > scion< / span > < span class = "plain-syntax" > , < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > rootstock< / span > < span class = "plain-syntax" > ) {< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > scion< / span > < span class = "plain-syntax" > == < / span > < span class = "identifier-syntax" > NULL< / span > < span class = "plain-syntax" > ) < / span > < span class = "identifier-syntax" > internal_error< / span > < span class = "plain-syntax" > (< / span > < span class = "string-syntax" > "scion is null"< / span > < span class = "plain-syntax" > );< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > rootstock< / span > < span class = "plain-syntax" > == < / span > < span class = "identifier-syntax" > NULL< / span > < span class = "plain-syntax" > ) < / span > < span class = "identifier-syntax" > internal_error< / span > < span class = "plain-syntax" > (< / span > < span class = "string-syntax" > "rootstock is null"< / span > < span class = "plain-syntax" > );< / span >
< span class = "plain-syntax" > < / span > < span class = "comment-syntax" > is the new node to be the only child of the old?< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > rootstock< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > down< / span > < span class = "plain-syntax" > == < / span > < span class = "identifier-syntax" > NULL< / span > < span class = "plain-syntax" > ) { < / span > < span class = "identifier-syntax" > rootstock< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > down< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > scion< / span > < span class = "plain-syntax" > ; < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > NULL< / span > < span class = "plain-syntax" > ; }< / span >
< span class = "plain-syntax" > < / span > < span class = "comment-syntax" > find youngest child of rootstock...< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > elder< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > NULL< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > for< / span > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > elder< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > rootstock< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > down< / span > < span class = "plain-syntax" > ; < / span > < span class = "identifier-syntax" > elder< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > next_alternative< / span > < span class = "plain-syntax" > ; < / span > < span class = "identifier-syntax" > elder< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > elder< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > next_alternative< / span > < span class = "plain-syntax" > ) ;< / span >
< span class = "plain-syntax" > < / span > < span class = "comment-syntax" > ...and make the new node its younger sibling< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > elder< / span > < span class = "plain-syntax" > -> < / span > < span class = "identifier-syntax" > next_alternative< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > scion< / span > < span class = "plain-syntax" > ; < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > elder< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< / pre >
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< p class = "commentary firstcommentary" > < a id = "SP8" class = "paragraph-anchor" > < / a > < b > § 8. < / b > And we can loop through these like so:
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< / p >
< pre class = "definitions code-font" > < span class = "definition-keyword" > define< / span > < span class = "identifier-syntax" > LOOP_THROUGH_ALTERNATIVES< / span > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > p< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > from< / span > < span class = "plain-syntax" > )< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > for< / span > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > p< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > from< / span > < span class = "plain-syntax" > ; < / span > < span class = "identifier-syntax" > p< / span > < span class = "plain-syntax" > ; < / span > < span class = "identifier-syntax" > p< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > p< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > next_alternative< / span > < span class = "plain-syntax" > )< / span >
< / pre >
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< p class = "commentary firstcommentary" > < a id = "SP9" class = "paragraph-anchor" > < / a > < b > § 9. Where we currently are in the text. < / b > Inform makes many traverses through the big parse tree, often modifying as it
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goes, and keeps track of its position so that it can make any problem messages
correctly refer to the location of the faulty text in the original source files.
< / p >
< p class = "commentary" > During such traverses, < span class = "extract" > < span class = "extract-syntax" > current_sentence< / span > < / span > is always the subtree being looked
at: it is always a child of the tree root, and is usually a < span class = "extract" > < span class = "extract-syntax" > SENTENCE_NT< / span > < / span >
node, hence the name.
< / p >
< pre class = "displayed-code all-displayed-code code-font" >
< span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > NULL< / span > < span class = "plain-syntax" > ;< / span >
< / pre >
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< p class = "commentary firstcommentary" > < a id = "SP10" class = "paragraph-anchor" > < / a > < b > § 10. General traversals. < / b > It's convenient to have a general system for traversing a syntax tree, visiting
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each node in the connected component of the tree root. C doesn't make this sort
of thing easy, though, so there follows a welter of boringly similar functions
with convoluted type signatures.
< / p >
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< p class = "commentary" > All these do basically the same thing. < a href = "2-st.html#SP10" class = "internal" > SyntaxTree::traverse< / a > calls a visitor
function on each node; < a href = "2-st.html#SP10" class = "internal" > SyntaxTree::traverse_from< / a > the same, but from a
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chosen start position, rather than the root of the tree.
< / p >
< p class = "commentary" > In this first version, the visitor function has type signature < span class = "extract" > < span class = "extract-syntax" > parse_node * -> void< / span > < / span > .
< / p >
< pre class = "displayed-code all-displayed-code code-font" >
< span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::traverse< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > , < / span > < span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *)) {< / span >
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< span class = "plain-syntax" > < / span > < a href = "2-st.html#SP10" class = "function-link" > < span class = "function-syntax" > SyntaxTree::traverse_from< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "identifier-syntax" > root_node< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > );< / span >
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< span class = "plain-syntax" > }< / span >
< span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::traverse_from< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > , < / span > < span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *)) {< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > SCS< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > for< / span > < span class = "plain-syntax" > (; < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ; < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > next< / span > < span class = "plain-syntax" > ) {< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-st.html#SP11" class = "function-link" > < span class = "function-syntax" > SyntaxTree::visitable< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > )) {< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-nt.html#SP11" class = "function-link" > < span class = "function-syntax" > NodeType::is_sentence< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > )) < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > );< / span >
< span class = "plain-syntax" > }< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-nt.html#SP10" class = "function-link" > < span class = "function-syntax" > NodeType::is_top_level< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > )) < / span > < a href = "2-st.html#SP10" class = "function-link" > < span class = "function-syntax" > SyntaxTree::traverse_from< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > down< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > );< / span >
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< span class = "plain-syntax" > }< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > SCS< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::traverse_run< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > , < / span > < span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *), < / span > < span class = "constant-syntax" > node_type_t< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > ) {< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > SCS< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > for< / span > < span class = "plain-syntax" > (; < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ; < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > next< / span > < span class = "plain-syntax" > ) {< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-pn.html#SP5" class = "function-link" > < span class = "function-syntax" > Node::get_type< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ) != < / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > ) < / span > < span class = "reserved-syntax" > break< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-st.html#SP11" class = "function-link" > < span class = "function-syntax" > SyntaxTree::visitable< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > )) {< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-nt.html#SP11" class = "function-link" > < span class = "function-syntax" > NodeType::is_sentence< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > )) < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ;< / span >
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< span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > );< / span >
< span class = "plain-syntax" > }< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-nt.html#SP10" class = "function-link" > < span class = "function-syntax" > NodeType::is_top_level< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > )) < / span > < a href = "2-st.html#SP10" class = "function-link" > < span class = "function-syntax" > SyntaxTree::traverse_from< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > down< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > );< / span >
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< span class = "plain-syntax" > }< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > SCS< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< / pre >
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< p class = "commentary firstcommentary" > < a id = "SP11" class = "paragraph-anchor" > < / a > < b > § 11. < / b > Note that any node not "visitable" is omitted, where the following function
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is the sole arbiter. This depends only on its node type.
< / p >
< pre class = "displayed-code all-displayed-code code-font" >
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< span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::visitable< / span > < button class = "popup" onclick = "togglePopup('usagePopup6')" > < span class = "comment-syntax" > ?< / span > < span class = "popuptext" id = "usagePopup6" > Usage of < span class = "code-font" > < span class = "function-syntax" > SyntaxTree::visitable< / span > < / span > :< br / > < a href = "2-st.html#SP10" > § 10< / a > , < a href = "2-st.html#SP12" > § 12< / a > , < a href = "2-st.html#SP13" > § 13< / a > , < a href = "2-st.html#SP14" > § 14< / a > , < a href = "2-st.html#SP15" > § 15< / a > , < a href = "2-st.html#SP16" > § 16< / a > , < a href = "2-st.html#SP17" > § 17< / a > , < a href = "2-st.html#SP18" > § 18< / a > < / span > < / button > < span class = "plain-syntax" > (< / span > < span class = "constant-syntax" > node_type_t< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > t< / span > < span class = "plain-syntax" > ) {< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-nt.html#SP10" class = "function-link" > < span class = "function-syntax" > NodeType::has_flag< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > t< / span > < span class = "plain-syntax" > , < / span > < span class = "constant-syntax" > DONT_VISIT_NFLAG< / span > < span class = "plain-syntax" > )) < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > FALSE< / span > < span class = "plain-syntax" > ;< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > TRUE< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< / pre >
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< p class = "commentary firstcommentary" > < a id = "SP12" class = "paragraph-anchor" > < / a > < b > § 12. < / b > And now the same thing, but where the visitor function has the type
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signature < span class = "extract" > < span class = "extract-syntax" > text_stream *, parse_node * -> void< / span > < / span > .
< / p >
< pre class = "displayed-code all-displayed-code code-font" >
< span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::traverse_text< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > text_stream< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > OUT< / span > < span class = "plain-syntax" > ,< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "identifier-syntax" > text_stream< / span > < span class = "plain-syntax" > *, < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *)) {< / span >
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< span class = "plain-syntax" > < / span > < a href = "2-st.html#SP12" class = "function-link" > < span class = "function-syntax" > SyntaxTree::traverse_text_from< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > OUT< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > root_node< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > );< / span >
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< span class = "plain-syntax" > }< / span >
< span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::traverse_text_from< / span > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > text_stream< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > OUT< / span > < span class = "plain-syntax" > , < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ,< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "identifier-syntax" > text_stream< / span > < span class = "plain-syntax" > *, < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *)) {< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > SCS< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > for< / span > < span class = "plain-syntax" > (; < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ; < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > next< / span > < span class = "plain-syntax" > ) {< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-st.html#SP11" class = "function-link" > < span class = "function-syntax" > SyntaxTree::visitable< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > )) {< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-nt.html#SP11" class = "function-link" > < span class = "function-syntax" > NodeType::is_sentence< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > )) < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ;< / span >
2020-05-11 17:21:29 +03:00
< span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "identifier-syntax" > OUT< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > );< / span >
< span class = "plain-syntax" > }< / span >
2022-09-05 02:08:32 +03:00
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-nt.html#SP10" class = "function-link" > < span class = "function-syntax" > NodeType::is_top_level< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > ))< / span >
< span class = "plain-syntax" > < / span > < a href = "2-st.html#SP12" class = "function-link" > < span class = "function-syntax" > SyntaxTree::traverse_text_from< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > OUT< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > down< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > );< / span >
2020-05-11 17:21:29 +03:00
< span class = "plain-syntax" > }< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > SCS< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< / pre >
2020-08-22 14:59:50 +03:00
< p class = "commentary firstcommentary" > < a id = "SP13" class = "paragraph-anchor" > < / a > < b > § 13. < / b > And now the same thing, but where the visitor function has the type
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signature < span class = "extract" > < span class = "extract-syntax" > parse_node *, int * -> void< / span > < / span > .
< / p >
< pre class = "displayed-code all-displayed-code code-font" >
< span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::traverse_intp< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > ,< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *, < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > *), < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > ) {< / span >
2020-05-19 18:36:50 +03:00
< span class = "plain-syntax" > < / span > < a href = "2-st.html#SP13" class = "function-link" > < span class = "function-syntax" > SyntaxTree::traverse_intp_from< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > root_node< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > );< / span >
2020-05-11 17:21:29 +03:00
< span class = "plain-syntax" > }< / span >
< span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::traverse_intp_from< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ,< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *, < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > *), < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > ) {< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > SCS< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > for< / span > < span class = "plain-syntax" > (; < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ; < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > next< / span > < span class = "plain-syntax" > ) {< / span >
2020-05-19 18:36:50 +03:00
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-st.html#SP11" class = "function-link" > < span class = "function-syntax" > SyntaxTree::visitable< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > )) {< / span >
2020-05-11 21:14:00 +03:00
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-nt.html#SP11" class = "function-link" > < span class = "function-syntax" > NodeType::is_sentence< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > )) < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ;< / span >
2020-05-11 17:21:29 +03:00
< span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > );< / span >
< span class = "plain-syntax" > }< / span >
2022-09-05 02:08:32 +03:00
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-nt.html#SP10" class = "function-link" > < span class = "function-syntax" > NodeType::is_top_level< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > ))< / span >
< span class = "plain-syntax" > < / span > < a href = "2-st.html#SP13" class = "function-link" > < span class = "function-syntax" > SyntaxTree::traverse_intp_from< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > down< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > );< / span >
2020-05-11 17:21:29 +03:00
< span class = "plain-syntax" > }< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > SCS< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< / pre >
2020-08-22 14:59:50 +03:00
< p class = "commentary firstcommentary" > < a id = "SP14" class = "paragraph-anchor" > < / a > < b > § 14. < / b > And the same thing, but where the visitor function has the type signature
2020-05-11 17:21:29 +03:00
< span class = "extract" > < span class = "extract-syntax" > parse_node *, int *, int * -> void< / span > < / span > .
< / p >
< pre class = "displayed-code all-displayed-code code-font" >
< span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::traverse_intp_intp< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > ,< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *, < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > *, < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > *), < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > , < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > Y< / span > < span class = "plain-syntax" > ) {< / span >
2020-05-19 18:36:50 +03:00
< span class = "plain-syntax" > < / span > < a href = "2-st.html#SP14" class = "function-link" > < span class = "function-syntax" > SyntaxTree::traverse_intp_intp_from< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > root_node< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > Y< / span > < span class = "plain-syntax" > );< / span >
2020-05-11 17:21:29 +03:00
< span class = "plain-syntax" > }< / span >
< span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::traverse_intp_intp_from< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ,< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *, < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > *, < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > *), < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > , < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > Y< / span > < span class = "plain-syntax" > ) {< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > SCS< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > for< / span > < span class = "plain-syntax" > (; < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ; < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > next< / span > < span class = "plain-syntax" > ) {< / span >
2020-05-19 18:36:50 +03:00
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-st.html#SP11" class = "function-link" > < span class = "function-syntax" > SyntaxTree::visitable< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > )) {< / span >
2020-05-11 21:14:00 +03:00
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-nt.html#SP11" class = "function-link" > < span class = "function-syntax" > NodeType::is_sentence< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > )) < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ;< / span >
2020-05-11 17:21:29 +03:00
< span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > Y< / span > < span class = "plain-syntax" > );< / span >
< span class = "plain-syntax" > }< / span >
2022-09-05 02:08:32 +03:00
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-nt.html#SP10" class = "function-link" > < span class = "function-syntax" > NodeType::is_top_level< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > ))< / span >
< span class = "plain-syntax" > < / span > < a href = "2-st.html#SP14" class = "function-link" > < span class = "function-syntax" > SyntaxTree::traverse_intp_intp_from< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > down< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > Y< / span > < span class = "plain-syntax" > );< / span >
2020-05-11 17:21:29 +03:00
< span class = "plain-syntax" > }< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > SCS< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< / pre >
2020-08-22 14:59:50 +03:00
< p class = "commentary firstcommentary" > < a id = "SP15" class = "paragraph-anchor" > < / a > < b > § 15. < / b > And now for < span class = "extract" > < span class = "extract-syntax" > parse_node *, parse_node ** -> void< / span > < / span > .
2020-05-11 17:21:29 +03:00
< / p >
< pre class = "displayed-code all-displayed-code code-font" >
< span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::traverse_nodep< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > ,< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *, < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > **), < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > **< / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > ) {< / span >
2020-05-19 18:36:50 +03:00
< span class = "plain-syntax" > < / span > < a href = "2-st.html#SP15" class = "function-link" > < span class = "function-syntax" > SyntaxTree::traverse_nodep_from< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > root_node< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > );< / span >
2020-05-11 17:21:29 +03:00
< span class = "plain-syntax" > }< / span >
< span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::traverse_nodep_from< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ,< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *, < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > **), < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > **< / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > ) {< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > SCS< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > for< / span > < span class = "plain-syntax" > (; < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ; < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > next< / span > < span class = "plain-syntax" > ) {< / span >
2020-05-19 18:36:50 +03:00
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-st.html#SP11" class = "function-link" > < span class = "function-syntax" > SyntaxTree::visitable< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > )) {< / span >
2020-05-11 21:14:00 +03:00
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-nt.html#SP11" class = "function-link" > < span class = "function-syntax" > NodeType::is_sentence< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > )) < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ;< / span >
2020-05-11 17:21:29 +03:00
< span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > );< / span >
< span class = "plain-syntax" > }< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-nt.html#SP10" class = "function-link" > < span class = "function-syntax" > NodeType::is_top_level< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > ))< / span >
< span class = "plain-syntax" > < / span > < a href = "2-st.html#SP15" class = "function-link" > < span class = "function-syntax" > SyntaxTree::traverse_nodep_from< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > down< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > );< / span >
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< span class = "plain-syntax" > }< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > SCS< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< / pre >
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< p class = "commentary firstcommentary" > < a id = "SP16" class = "paragraph-anchor" > < / a > < b > § 16. < / b > This is a tricksier sort of traverse, which tells the visitor function the
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heading node it belongs to. The visitor function now has type signature
< span class = "extract" > < span class = "extract-syntax" > parse_node_tree *, parse_node *, parse_node *, int * -> void< / span > < / span > , where the
two nodes are the one being visited and its heading, respectively.
< / p >
< pre class = "displayed-code all-displayed-code code-font" >
< span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::traverse_headingwise< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > ,< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > *, < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *, < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *, < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > *), < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > N< / span > < span class = "plain-syntax" > ) {< / span >
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< span class = "plain-syntax" > < / span > < a href = "2-st.html#SP16" class = "function-link" > < span class = "function-syntax" > SyntaxTree::traverse_headingwise_from< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > root_node< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > NULL< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > N< / span > < span class = "plain-syntax" > );< / span >
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< span class = "plain-syntax" > }< / span >
< span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::traverse_headingwise_from< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > , < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ,< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > *, < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *, < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *, < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > *),< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > last_h0< / span > < span class = "plain-syntax" > , < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > N< / span > < span class = "plain-syntax" > ) {< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > SCS< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > for< / span > < span class = "plain-syntax" > (; < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ; < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > next< / span > < span class = "plain-syntax" > ) {< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-st.html#SP11" class = "function-link" > < span class = "function-syntax" > SyntaxTree::visitable< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > )) {< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-nt.html#SP11" class = "function-link" > < span class = "function-syntax" > NodeType::is_sentence< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > )) < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > last_h0< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > N< / span > < span class = "plain-syntax" > );< / span >
< span class = "plain-syntax" > }< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-nt.html#SP10" class = "function-link" > < span class = "function-syntax" > NodeType::is_top_level< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > )) {< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > H0< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > last_h0< / span > < span class = "plain-syntax" > ;< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > ((< / span > < a href = "2-pn.html#SP5" class = "function-link" > < span class = "function-syntax" > Node::is< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > , < / span > < span class = "constant-syntax" > HEADING_NT< / span > < span class = "plain-syntax" > )) & & < / span >
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< span class = "plain-syntax" > (< / span > < a href = "2-na.html#SP7" class = "function-link" > < span class = "function-syntax" > Annotations::read_int< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > , < / span > < span class = "constant-syntax" > heading_level_ANNOT< / span > < span class = "plain-syntax" > ) == < / span > < span class = "constant-syntax" > 0< / span > < span class = "plain-syntax" > ))< / span >
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< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > H0< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ;< / span >
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< span class = "plain-syntax" > < / span > < a href = "2-st.html#SP16" class = "function-link" > < span class = "function-syntax" > SyntaxTree::traverse_headingwise_from< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > down< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > H0< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > N< / span > < span class = "plain-syntax" > );< / span >
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< span class = "plain-syntax" > }< / span >
< span class = "plain-syntax" > }< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > SCS< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< / pre >
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< p class = "commentary firstcommentary" > < a id = "SP17" class = "paragraph-anchor" > < / a > < b > § 17. < / b > And this is another variation: a traverse to find a node with a particular
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property. The process halts as soon as the visitor function, which has
signature < span class = "extract" > < span class = "extract-syntax" > parse_node *, parse_node *, parse_node ** -> int< / span > < / span > , returns < span class = "extract" > < span class = "extract-syntax" > TRUE< / span > < / span > ,
and the idea is that the visitor will store its result in the < span class = "extract" > < span class = "extract-syntax" > parse_node *< / span > < / span >
pointed to by its last argument.
< / p >
< p class = "commentary" > Note that this one doesn't record its position in < span class = "extract" > < span class = "extract-syntax" > current_sentence< / span > < / span > . The
fuss over top-level nodes is to ensure recursion even though top-level
nodes are not visitable; otherwise the function would never find anything
because no visitable nodes would ever be reached.
< / p >
< pre class = "displayed-code all-displayed-code code-font" >
< span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::traverse_to_find< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > ,< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *, < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *, < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > **),< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > **< / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > ) {< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > < / span > < a href = "2-st.html#SP17" class = "function-link" > < span class = "function-syntax" > SyntaxTree::traverse_to_find_from< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > root_node< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > NULL< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > );< / span >
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< span class = "plain-syntax" > }< / span >
< span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::traverse_to_find_from< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ,< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *, < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *, < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > **),< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > from< / span > < span class = "plain-syntax" > , < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > **< / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > ) {< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > for< / span > < span class = "plain-syntax" > (; < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ; < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > next< / span > < span class = "plain-syntax" > ) {< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-st.html#SP11" class = "function-link" > < span class = "function-syntax" > SyntaxTree::visitable< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > ))< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > ((*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > from< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > ))< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > TRUE< / span > < span class = "plain-syntax" > ;< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-nt.html#SP10" class = "function-link" > < span class = "function-syntax" > NodeType::is_top_level< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > ))< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-st.html#SP17" class = "function-link" > < span class = "function-syntax" > SyntaxTree::traverse_to_find_from< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > down< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > ))< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > TRUE< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > FALSE< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< / pre >
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< p class = "commentary firstcommentary" > < a id = "SP18" class = "paragraph-anchor" > < / a > < b > § 18. < / b > And still another. This one traverses only up to a given stop position,
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and the visitor has signature < span class = "extract" > < span class = "extract-syntax" > parse_node *, void ** -> void< / span > < / span > , the idea
being that the final < span class = "extract" > < span class = "extract-syntax" > void **< / span > < / span > is a pointer to a general object pointer.
This is the sort of thing which brings C into disrepute, but we don't use
it very much.
< / p >
< pre class = "displayed-code all-displayed-code code-font" >
< span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::traverse_up_to_ip< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > , < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > end< / span > < span class = "plain-syntax" > ,< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *, < / span > < span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > **), < / span > < span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > **< / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > ) {< / span >
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< span class = "plain-syntax" > < / span > < a href = "2-st.html#SP18" class = "function-link" > < span class = "function-syntax" > SyntaxTree::traverse_from_up_to_ip< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > end< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > root_node< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > );< / span >
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< span class = "plain-syntax" > }< / span >
< span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::traverse_from_up_to_ip< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > end< / span > < span class = "plain-syntax" > , < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ,< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *, < / span > < span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > **), < / span > < span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > **< / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > ) {< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > SCS< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > for< / span > < span class = "plain-syntax" > (; < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ; < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > next< / span > < span class = "plain-syntax" > ) {< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > == < / span > < span class = "identifier-syntax" > end< / span > < span class = "plain-syntax" > ) { < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > SCS< / span > < span class = "plain-syntax" > ; < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > TRUE< / span > < span class = "plain-syntax" > ; }< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-st.html#SP11" class = "function-link" > < span class = "function-syntax" > SyntaxTree::visitable< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > )) {< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-nt.html#SP11" class = "function-link" > < span class = "function-syntax" > NodeType::is_sentence< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > )) < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > (*< / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > )(< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > );< / span >
< span class = "plain-syntax" > }< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-nt.html#SP10" class = "function-link" > < span class = "function-syntax" > NodeType::is_top_level< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > node_type< / span > < span class = "plain-syntax" > )) {< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-st.html#SP18" class = "function-link" > < span class = "function-syntax" > SyntaxTree::traverse_from_up_to_ip< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > end< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > pn< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > down< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > visitor< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > X< / span > < span class = "plain-syntax" > )) {< / span >
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< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > SCS< / span > < span class = "plain-syntax" > ; < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > TRUE< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< span class = "plain-syntax" > }< / span >
< span class = "plain-syntax" > }< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > current_sentence< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > SCS< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > FALSE< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< / pre >
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< p class = "commentary firstcommentary" > < a id = "SP19" class = "paragraph-anchor" > < / a > < b > § 19. Cautious traverses. < / b > When logging or verifying the tree, we cannot use the carefree functions
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above: the tree might be malformed. As a way to detect cycles, we call for
a new "traverse token" — just a unique integer value — and mark all nodes
visited with that value.
< / p >
< pre class = "displayed-code all-displayed-code code-font" >
< span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > pn_log_token< / span > < span class = "plain-syntax" > = < / span > < span class = "constant-syntax" > 0< / span > < span class = "plain-syntax" > ;< / span >
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< span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::new_traverse_token< / span > < button class = "popup" onclick = "togglePopup('usagePopup7')" > < span class = "comment-syntax" > ?< / span > < span class = "popuptext" id = "usagePopup7" > Usage of < span class = "code-font" > < span class = "function-syntax" > SyntaxTree::new_traverse_token< / span > < / span > :< br / > Parse Nodes - < a href = "2-pn.html#SP16" > § 16< / a > < br / > Tree Verification - < a href = "2-tv.html#SP1" > § 1< / a > < / span > < / button > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > ) {< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > ++< / span > < span class = "identifier-syntax" > pn_log_token< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< / pre >
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< p class = "commentary firstcommentary" > < a id = "SP20" class = "paragraph-anchor" > < / a > < b > § 20. Toggling log output. < / b > Various modules conventionally use this global setting to toggle debugging
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log output:
< / p >
< pre class = "displayed-code all-displayed-code code-font" >
< span class = "reserved-syntax" > int< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::is_trace_set< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > ) {< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > trace_sentences< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::set_trace< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > ) {< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > trace_sentences< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > TRUE< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::clear_trace< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > ) {< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > trace_sentences< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > FALSE< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< span class = "reserved-syntax" > void< / span > < span class = "plain-syntax" > < / span > < span class = "function-syntax" > SyntaxTree::toggle_trace< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node_tree< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > ) {< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > trace_sentences< / span > < span class = "plain-syntax" > = (< / span > < span class = "identifier-syntax" > T< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > trace_sentences< / span > < span class = "plain-syntax" > )?< / span > < span class = "identifier-syntax" > FALSE:TRUE< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< / pre >
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< p class = "commentary firstcommentary" > < a id = "SP21" class = "paragraph-anchor" > < / a > < b > § 21. Ambiguity subtrees. < / b > The following function adds a new < span class = "extract" > < span class = "extract-syntax" > reading< / span > < / span > to an < span class = "extract" > < span class = "extract-syntax" > existing< / span > < / span > interpretation
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of some wording < span class = "extract" > < span class = "extract-syntax" > W< / span > < / span > , and return the node now representing. For example,
suppose the text "orange" can be read as a noun for fruit, a noun for colour,
or an adjective, resulting in nodes < span class = "extract" > < span class = "extract-syntax" > fruit_node< / span > < / span > and < span class = "extract" > < span class = "extract-syntax" > colour_node< / span > < / span > and < span class = "extract" > < span class = "extract-syntax" > adj_node< / span > < / span > .
Then:
< / p >
< ul class = "items" > < li > (a) < span class = "extract" > < span class = "extract-syntax" > SyntaxTree::add_reading(NULL, fruit_node, W)< / span > < / span > returns < span class = "extract" > < span class = "extract-syntax" > noun_node< / span > < / span > ,
< / li > < li > (b) but < span class = "extract" > < span class = "extract-syntax" > SyntaxTree::add_reading(fruit_node, colour_node, W)< / span > < / span > returns this subtree:
< / li > < / ul >
< pre class = "displayed-code all-displayed-code code-font" >
< span class = "plain-syntax" > AMBIGUITY_NT A< / span >
< span class = "plain-syntax" > fruit_node< / span >
< span class = "plain-syntax" > colour_node< / span >
< / pre >
< ul class = "items" > < li > (c) and < span class = "extract" > < span class = "extract-syntax" > SyntaxTree::add_reading(A, adj_node, W)< / span > < / span > returns the subtree:
< / li > < / ul >
< pre class = "displayed-code all-displayed-code code-font" >
< span class = "plain-syntax" > AMBIGUITY_NT A< / span >
< span class = "plain-syntax" > fruit_node< / span >
< span class = "plain-syntax" > colour_node< / span >
< span class = "plain-syntax" > adj_node< / span >
< / pre >
< p class = "commentary" > Thus it accumulates possible readings of a given text.
< / p >
< p class = "commentary" > A complication is that the following callback function is offered the chance
to amend this process in individual cases; it's called whenever < span class = "extract" > < span class = "extract-syntax" > reading< / span > < / span >
is about to become one of the alternatives to some existing < span class = "extract" > < span class = "extract-syntax" > E< / span > < / span > . If it returns
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< span class = "extract" > < span class = "extract-syntax" > TRUE< / span > < / span > , we assume it has done something of its own already, and do nothing
further.
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< / p >
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< p class = "commentary" > (< a href = "../inform7/index.html" class = "internal" > inform7< / a > uses this to rearrange ambiguous phrase invocations to be sorted
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out in type-checking: see < a href = "../values-module/5-dsh.html" class = "internal" > Dash (in values)< / a > .)
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< / p >
< pre class = "displayed-code all-displayed-code code-font" >
< span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "function-syntax" > SyntaxTree::add_reading< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > existing< / span > < span class = "plain-syntax" > , < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > reading< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > wording< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > W< / span > < span class = "plain-syntax" > ) {< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > existing< / span > < span class = "plain-syntax" > == < / span > < span class = "identifier-syntax" > NULL< / span > < span class = "plain-syntax" > ) < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > reading< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-pn.html#SP5" class = "function-link" > < span class = "function-syntax" > Node::is< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > reading< / span > < span class = "plain-syntax" > , < / span > < span class = "constant-syntax" > UNKNOWN_NT< / span > < span class = "plain-syntax" > )) < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > existing< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-pn.html#SP5" class = "function-link" > < span class = "function-syntax" > Node::is< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > reading< / span > < span class = "plain-syntax" > , < / span > < span class = "constant-syntax" > AMBIGUITY_NT< / span > < span class = "plain-syntax" > )) < / span > < span class = "identifier-syntax" > reading< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > reading< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > down< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < a href = "2-pn.html#SP5" class = "function-link" > < span class = "function-syntax" > Node::is< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > existing< / span > < span class = "plain-syntax" > , < / span > < span class = "constant-syntax" > AMBIGUITY_NT< / span > < span class = "plain-syntax" > )) {< / span >
< span class = "plain-syntax" > #< / span > < span class = "identifier-syntax" > ifdef< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > AMBIGUITY_JOIN_SYNTAX_CALLBACK< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > for< / span > < span class = "plain-syntax" > (< / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > E< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > existing< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > down< / span > < span class = "plain-syntax" > ; < / span > < span class = "identifier-syntax" > E< / span > < span class = "plain-syntax" > ; < / span > < span class = "identifier-syntax" > E< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > E< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > next_alternative< / span > < span class = "plain-syntax" > )< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > AMBIGUITY_JOIN_SYNTAX_CALLBACK< / span > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > E< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > reading< / span > < span class = "plain-syntax" > ))< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > existing< / span > < span class = "plain-syntax" > ;< / span >
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< span class = "plain-syntax" > #< / span > < span class = "identifier-syntax" > endif< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > L< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > existing< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > down< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > while< / span > < span class = "plain-syntax" > ((< / span > < span class = "identifier-syntax" > L< / span > < span class = "plain-syntax" > ) & & (< / span > < span class = "identifier-syntax" > L< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > next_alternative< / span > < span class = "plain-syntax" > )) < / span > < span class = "identifier-syntax" > L< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > L< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > next_alternative< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > L< / span > < span class = "plain-syntax" > -> < / span > < span class = "identifier-syntax" > next_alternative< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > reading< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > existing< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< span class = "plain-syntax" > #< / span > < span class = "identifier-syntax" > ifdef< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > AMBIGUITY_JOIN_SYNTAX_CALLBACK< / span >
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< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > if< / span > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > AMBIGUITY_JOIN_SYNTAX_CALLBACK< / span > < span class = "plain-syntax" > (< / span > < span class = "identifier-syntax" > existing< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > reading< / span > < span class = "plain-syntax" > )) < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > existing< / span > < span class = "plain-syntax" > ;< / span >
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< span class = "plain-syntax" > #< / span > < span class = "identifier-syntax" > endif< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > parse_node< / span > < span class = "plain-syntax" > *< / span > < span class = "identifier-syntax" > A< / span > < span class = "plain-syntax" > = < / span > < a href = "2-pn.html#SP3" class = "function-link" > < span class = "function-syntax" > Node::new_with_words< / span > < / a > < span class = "plain-syntax" > (< / span > < span class = "constant-syntax" > AMBIGUITY_NT< / span > < span class = "plain-syntax" > , < / span > < span class = "identifier-syntax" > W< / span > < span class = "plain-syntax" > );< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > A< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > down< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > existing< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > A< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > down< / span > < span class = "plain-syntax" > -> < / span > < span class = "element-syntax" > next_alternative< / span > < span class = "plain-syntax" > = < / span > < span class = "identifier-syntax" > reading< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > < / span > < span class = "reserved-syntax" > return< / span > < span class = "plain-syntax" > < / span > < span class = "identifier-syntax" > A< / span > < span class = "plain-syntax" > ;< / span >
< span class = "plain-syntax" > }< / span >
< / pre >
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< nav role = "progress" > < div class = "progresscontainer" >
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< ul class = "progressbar" > < li class = "progressprev" > < a href = "1-sm.html" > ❮ < / a > < / li > < li class = "progresschapter" > < a href = "P-wtmd.html" > P< / a > < / li > < li class = "progresschapter" > < a href = "1-sm.html" > 1< / a > < / li > < li class = "progresscurrentchapter" > 2< / li > < li class = "progresscurrent" > st< / li > < li class = "progresssection" > < a href = "2-nt.html" > nt< / a > < / li > < li class = "progresssection" > < a href = "2-pn.html" > pn< / a > < / li > < li class = "progresssection" > < a href = "2-na.html" > na< / a > < / li > < li class = "progresssection" > < a href = "2-tv.html" > tv< / a > < / li > < li class = "progresssection" > < a href = "2-spc.html" > spc< / a > < / li > < li class = "progresschapter" > < a href = "3-snt.html" > 3< / a > < / li > < li class = "progressnext" > < a href = "2-nt.html" > ❯ < / a > < / li > < / ul > < / div >
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< / nav > <!-- End of weave -->
< / main >
< / body >
< / html >
