Logtalk 2.26.2 files.

git-svn-id: https://yap.svn.sf.net/svnroot/yap/trunk@1487 b08c6af1-5177-4d33-ba66-4b1c6b8b522a

Logtalk/examples/dcgs/sentences.lgt

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+
+
+% Categories allows us to neatly organize the different "kinds"
+% of words on this example: determiners, nouns, and verbs
+
+
+:- category(determiners).
+
+	:- private(determiner//0).	% private category non-terminals become private
+								% non-terminals of the objects importing the category
+	determiner --> [the].
+	determiner --> [a].
+
+:- end_category.
+
+
+:- category(nouns).
+
+	:- private(noun//0).
+
+	noun --> [boy].
+	noun --> [girl].
+
+:- end_category.
+
+
+:- category(verbs).
+
+	:- private(verb//0).
+
+	verb --> [likes].
+	verb --> [hates].
+
+:- end_category.
+
+
+:- object(sentence,
+	implements(parsep),
+	imports(determiners, nouns, verbs)).
+
+	parse(List, true) :-
+		phrase(sentence, List).
+	parse(_, false).
+
+	sentence --> noun_phrase, verb_phrase.
+
+	noun_phrase --> ::determiner, ::noun.	% the ::/1 control construct is used to call grammar
+	noun_phrase --> ::noun.					% rules encapsulated on the imported categories
+
+	verb_phrase --> ::verb.
+	verb_phrase --> ::verb, noun_phrase.
+
+:- end_object.