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65 lines
2.5 KiB
OpenEdge ABL
65 lines
2.5 KiB
OpenEdge ABL
[Lexicon::] Lexicon.
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This section provides a simple API for storing and retrieving lexicon entries.
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@ The user creates new lexicon entries with:
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=
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excerpt_meaning *Lexicon::register(
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unsigned int meaning_code, wording W, general_pointer data) {
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if (Wordings::empty(W)) internal_error("tried to register empty excerpt meaning");
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return ExcerptMeanings::register(meaning_code, W, data);
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}
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@ //excerpt_meaning// objects are intended to be fairly opaque, but the user
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can call this to extract their attached data:
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=
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general_pointer Lexicon::get_data(excerpt_meaning *em) {
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return em->data;
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}
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@ Entries can be retrieved either the regular way, or in "maximal mode",
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which tries to parse a maximal-length initial portion of |W| rather than
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necessarily the whole thing. For example, that mode might peel off the
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adjective "fixed in place" from wording |W| which was "fixed in place door".
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This is very much the exception: we almost always want to match the whole of |W|.
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It might seem symmetrical that the return value should be an //excerpt_meaning//.
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But that wouldn't enable us to return multiple results in the (frequent) case
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of ambiguity. Instead, we need to return a list of possibilities, and we do
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that by returning fragment of syntax tree material, using the infrastructure
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from //syntax//. This will be a list of nodes joined by |->next_alternative| limks.
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This list of nodes is disposable -- even if it is a copy of something from the
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syntax tree, it is never the only copy. It can freely be ignored or changed.
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A return value of |NULL| means there were no results at all.
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(*) If a meaning was registered in such a way that its |data| actually was a
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node from the syntax tree, then the result is a copy of that node.
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(*) If not then the result is a node with the meaning code as its node type,
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and the excerpt meaning can be recovered from it using |Node::get_meaning|.
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=
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parse_node *Lexicon::retrieve(unsigned int mc_bitmap, wording W) {
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return FromLexicon::parse(mc_bitmap, W);
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}
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int lexicon_in_maximal_mode = FALSE;
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parse_node *Lexicon::retrieve_longest_initial_segment(unsigned int mc_bitmap,
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wording W) {
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int s = lexicon_in_maximal_mode;
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lexicon_in_maximal_mode = TRUE;
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parse_node *p = FromLexicon::parse(mc_bitmap, W);
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lexicon_in_maximal_mode = s;
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return p;
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}
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@ As a bonus, since the lexicon uses quite a convenient hash-coding system
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for excerpts, the following is available for anyone wanting to take advantage:
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=
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int Lexicon::wording_hash(wording W) {
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return ExcerptMeanings::hash_code(W);
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}
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