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100 lines
3.4 KiB
OpenEdge ABL
100 lines
3.4 KiB
OpenEdge ABL
[IdentifierFinders::] Identifier Finders.
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@ Suppose we have an identifier name, say |BlkValueCreate|, which we think
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refers to some symbol in an Inter tree. How do we find it, coming up with
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the right |inter_symbol|?
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The answer must depend on context, so the question really has to be "with
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the conventions given by this |identifier_finder|, what |inter_symbol|
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does this name correspond to?".
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@d MAX_IDENTIFIER_PRIORITIES 3
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=
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typedef struct identifier_finder {
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int no_priorities;
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struct inter_symbols_table *priorities[MAX_IDENTIFIER_PRIORITIES];
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} identifier_finder;
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@ The most basic set of conventions only allows us to see names visible
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everywhere:
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=
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identifier_finder IdentifierFinders::common_names_only(void) {
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identifier_finder finder;
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finder.no_priorities = 0;
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return finder;
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}
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@ But we can add to that by providing up to three symbols tables to search
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in preference order (first match wins):
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=
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void IdentifierFinders::next_priority(identifier_finder *finder,
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inter_symbols_table *where) {
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if (finder->no_priorities >= MAX_IDENTIFIER_PRIORITIES)
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internal_error("too many identifier finder priorities");
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finder->priorities[finder->no_priorities++] = where;
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}
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@ And here goes.
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=
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inter_symbol *IdentifierFinders::find(inter_tree *I, text_stream *name,
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identifier_finder finder) {
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if (Str::get_at(name, 0) == 0x00A7)
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@<Interpret this as an absolute URL@>
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else
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@<Interpret this as an identifier@>;
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LOG("Defeated on %S\n", name);
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internal_error("unable to find identifier");
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return NULL;
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}
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@ If the name begins with this magic character, we interpret it as an absolute
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URL within the tree -- the conventions are then unimportant: either the symbol
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exists where we said it is, or nothing is found. And in that case we will
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halt with an internal error: so this must be done speculatively.
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@<Interpret this as an absolute URL@> =
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TEMPORARY_TEXT(SR)
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Str::copy(SR, name);
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Str::delete_first_character(SR);
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Str::delete_last_character(SR);
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inter_symbol *S = InterSymbolsTable::URL_to_symbol(I, SR);
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DISCARD_TEXT(SR)
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if (S) return S;
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@ Here, though, if all attempts to find the identifier fail, we in effect
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force it to exist by creating a plug with this name, and then returning that.
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So the above internal error cannot occur.
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@<Interpret this as an identifier@> =
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for (int i = 0; i < finder.no_priorities; i++) {
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inter_symbol *S = InterSymbolsTable::symbol_from_name(finder.priorities[i], name);
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if (S) return S;
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}
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inter_symbol *S = LargeScale::find_architectural_symbol(I, name);
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if (S) return S;
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S = InterSymbolsTable::symbol_from_name(LargeScale::connectors_scope(I), name);
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if (S) return S;
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S = InterSymbolsTable::symbol_from_name(LargeScale::main_scope(I), name);
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if (S) return S;
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S = InterNames::to_symbol(HierarchyLocations::find_by_name(I, name));
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if (S) return S;
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@ A small variation. Note that a token can be marked explicitly with an iname
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to which it corresponds; if it has been, then this overrides the finding process,
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because the symbol which that iname incarnates as must be the right one.
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=
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inter_symbol *IdentifierFinders::find_token(inter_tree *I, inter_schema_token *t,
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identifier_finder finder) {
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if (t->as_quoted) return InterNames::to_symbol(t->as_quoted);
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#ifdef CORE_MODULE
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local_variable *lvar = LocalVariables::by_identifier(t->material);
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if (lvar) return LocalVariables::declare(lvar);
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#endif
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return IdentifierFinders::find(I, t->material, finder);
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}
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