mirror of
https://github.com/ganelson/inform.git
synced 2024-07-05 08:34:22 +03:00
114 lines
5.1 KiB
OpenEdge ABL
114 lines
5.1 KiB
OpenEdge ABL
|
How To Include This Module.
|
||
|
|
||
|
What to do to make use of the syntax module in a new command-line tool.
|
||
|
|
||
|
@h Status.
|
||
|
The syntax module provided as one of the "shared" Inform modules, which means
|
||
|
that it was built with a view to potential incorporation in multiple tools.
|
||
|
It can be found, for example, in //inform7//, //inbuild// and //syntax-test//,
|
||
|
among others. //syntax-test// may be useful as a minimal example of a tool
|
||
|
using //syntax//.
|
||
|
|
||
|
By convention, the modules considered as "shared" have no dependencies on
|
||
|
other modules except for //foundation// and other "shared" modules.
|
||
|
|
||
|
A tool can import //syntax// only if it also imports //foundation// and
|
||
|
//words//.
|
||
|
|
||
|
@h Importing the module.
|
||
|
We'll use the term "parent" to mean the tool which is importing //syntax//,
|
||
|
that is, which will include its code and be able to use it. As with any
|
||
|
imported module,
|
||
|
(*) The contents page of the parent's web must identify and locate the
|
||
|
module:
|
||
|
= (text as Inweb)
|
||
|
Import: somepath/syntax
|
||
|
=
|
||
|
(*) The parent must call |SyntaxModule::start()| just after it starts up, and
|
||
|
|SyntaxModule::end()| just before it shuts down. (But just after, and just
|
||
|
before, the corresponding calls to //foundation//.)
|
||
|
|
||
|
But in addition, the parent of //syntax// must define some Preform grammar:
|
||
|
|
||
|
(*) |<language-modifying-sentence>| to recognise sentences modifying the
|
||
|
language which is currently being parsed;
|
||
|
(*) |<structural-sentence>| to recognise structurally important sentences;
|
||
|
(*) |<dividing-sentence>| to recognise sentences which divide up the text,
|
||
|
normally headings;
|
||
|
(*) |<comma-divisible-sentence>| to recognise sentences where a comma plays
|
||
|
a role normally expected to be played by a colon.
|
||
|
|
||
|
Though compulsory, these don't need to do much: see //syntax-test: Unit Tests//.
|
||
|
|
||
|
@h Using callbacks.
|
||
|
Shared modules like this one are tweaked in behaviour by defining "callback
|
||
|
functions". This means that the parent might provide a function of its own
|
||
|
which would answer a question put to it by the module, or take some action
|
||
|
on behalf of the module: it's a callback in the sense that the parent is
|
||
|
normally calling the module, but then the module calls the parent back to
|
||
|
ask for data or action.
|
||
|
|
||
|
The parent must indicate which function to use by defining a constant with
|
||
|
a specific name as being equal to that function's name. A fictional example
|
||
|
would be
|
||
|
= (text as Inweb)
|
||
|
@d EXPRESS_SURPRISE_SYNTAX_CALLBACK Emotions::gosh
|
||
|
|
||
|
=
|
||
|
void Emotions::gosh(text_stream *OUT) {
|
||
|
WRITE("Good gracious!\n");
|
||
|
}
|
||
|
=
|
||
|
The syntax module has many callbacks, but they are all optional. The following
|
||
|
alphabetical list has references to fuller explanations:
|
||
|
|
||
|
(*) |AMBIGUITY_JOIN_SYNTAX_CALLBACK| can divert ambiguous readings and prevent
|
||
|
them from being added to a syntax tree: see //SyntaxTree::add_reading//.
|
||
|
|
||
|
(*) |ANNOTATION_COPY_SYNTAX_CALLBACK| can perform deep rather than shallow
|
||
|
copies of node annotations when these are essential: see //Annotations::copy//.
|
||
|
|
||
|
(*) |ANNOTATION_PERMISSIONS_SYNTAX_CALLBACK|, |MORE_ANNOTATION_PERMISSIONS_SYNTAX_CALLBACK|
|
||
|
and |EVEN_MORE_ANNOTATION_PERMISSIONS_SYNTAX_CALLBACK| gives permission for nodes
|
||
|
of given types to have annotations with given IDs, and effectively provides a
|
||
|
way to create custom annotations: see //Annotations::make_annotation_allowed_table//.
|
||
|
|
||
|
(*) |BEGIN_OR_END_HERE_SYNTAX_CALLBACK| is called when a new extension beginning
|
||
|
or ending sentence is found in the source text being broken into sentences:
|
||
|
see //Sentences::make_node//.
|
||
|
|
||
|
(*) |LANGUAGE_ELEMENT_SYNTAX_CALLBACK| is called when a sentence is found matching
|
||
|
the nonterminal |<language-modifying-sentence>|: see //Sentences::make_node//.
|
||
|
|
||
|
(*) |LOG_UNENUMERATED_NODE_TYPES_SYNTAX_CALLBACK| is called to log a node type
|
||
|
not recognised as one of the enumerated |*_NT| values: see //NodeType::log//.
|
||
|
|
||
|
(*) |NEW_HEADING_SYNTAX_CALLBACK| is called when a new heading sentence is found
|
||
|
in the source text being broken into sentences: see //Sentences::make_node//.
|
||
|
|
||
|
(*) |NEW_HEADING_TREE_SYNTAX_CALLBACK| is called when a new syntax tree is being
|
||
|
created, and needs to be given a matching tree of headings: see //SyntaxTree::new//.
|
||
|
|
||
|
(*) |NODE_METADATA_SETUP_SYNTAX_CALLBACK|, |MORE_NODE_METADATA_SETUP_SYNTAX_CALLBACK|
|
||
|
and |EVEN_MORE_NODE_METADATA_SETUP_SYNTAX_CALLBACK| adds new syntax tree node
|
||
|
types: see //NodeType::metadata_setup//.
|
||
|
|
||
|
(*) |PARENTAGE_EXCEPTIONS_SYNTAX_CALLBACK| allows exceptions to the rules about
|
||
|
which nodes in a syntax tree can be parents of which other nodes: see
|
||
|
//NodeType::parentage_allowed//.
|
||
|
|
||
|
(*) |PARENTAGE_PERMISSIONS_SYNTAX_CALLBACK|, |MORE_PARENTAGE_PERMISSIONS_SYNTAX_CALLBACK|
|
||
|
and |EVEN_MORE_PARENTAGE_PERMISSIONS_SYNTAX_CALLBACK| adds permissions for nodes
|
||
|
to be parents of each other: see //NodeType::make_parentage_allowed_table//.
|
||
|
|
||
|
(*) |PROBLEM_SYNTAX_CALLBACK| is called when a syntax error is found, and can
|
||
|
prevent this from being issued to the terminal as an error message: see
|
||
|
//Sentences::syntax_problem//.
|
||
|
|
||
|
(*) |NEW_NONSTRUCTURAL_SENTENCE_SYNTAX_CALLBACK| is called when a new, regular
|
||
|
sentence is found in the source text being broken into sentences: see
|
||
|
//Sentences::make_node//.
|
||
|
|
||
|
(*) |IS_SENTENCE_NODE_SYNTAX_CALLBACK| is asked whether a given node represents
|
||
|
a regular sentence or not: see //NodeType::is_sentence//.
|