add examples/ttuser - show custom tokens/pprint

examples/SConscript

@@ -6,8 +6,9 @@ example = env.Clone()
 example.Append(LIBS="hammer", LIBPATH="../src")
 
 dns = example.Program('dns', ['dns.c', 'rr.c', 'dns_common.c'])
+ttuser = example.Program('ttuser', 'ttuser.c')
 base64 = example.Program('base64', 'base64.c')
 base64_sem1 = example.Program('base64_sem1', 'base64_sem1.c')
 base64_sem2 = example.Program('base64_sem2', 'base64_sem2.c')
 ties = example.Program('ties', ['ties.c', 'grammar.c'])
-env.Alias("examples", [dns, base64, base64_sem1, base64_sem2, ties])
+env.Alias("examples", [dns, ttuser, base64, base64_sem1, base64_sem2, ties])
\ No newline at end of file

examples/ttuser.c

+/*
+ * Example parser that demonstrates the use of user-defined token types.
+ *
+ * Note the custom printer function that hooks into h_pprint().
+ */
+
+#include "../src/hammer.h"
+#include "../src/glue.h"
+
+
+/*
+ * custom tokens
+ */
+
+HTokenType TT_SUBJ, TT_PRED, TT_OBJ, TT_ADJ, TT_ADVC;
+
+void
+pprint(FILE *stream, const HParsedToken *tok, int indent, int delta)
+{
+	/* 
+	 * Pretty-printer rules:
+	 *
+	 *  - Output 'indent' spaces after every newline you produce.
+	 *  - Do not add indent on the first line of output.
+	 *  - Do not add a trailing newline.
+	 *  - Indent sub-objects by adding 'delta' to 'indent'.
+	 */
+
+	if (((HParsedToken *)tok->user)->token_type == TT_SEQUENCE)
+		fprintf(stream, "\n%*s", indent, "");
+	h_pprint(stream, tok->user, indent, delta);
+}
+
+/* XXX define umamb_sub as well */
+
+void
+init(void)
+{
+	TT_SUBJ = h_allocate_token_new("subject", NULL, pprint);
+	TT_PRED = h_allocate_token_new("predicate", NULL, pprint);
+	TT_OBJ  = h_allocate_token_new("object", NULL, pprint);
+	TT_ADJ  = h_allocate_token_new("adjective", NULL, pprint);
+	TT_ADVC = h_allocate_token_new("adverbial clause", NULL, pprint);
+}
+
+
+/*
+ * semantic actions
+ *
+ * Normally these would be more interesting, but for this example, we just wrap
+ * our tokens in their intended types.
+ */
+HParsedToken *act_subj(const HParseResult *p, void *u) {
+	return H_MAKE(SUBJ, (void *)p->ast);
+}
+HParsedToken *act_pred(const HParseResult *p, void *u) {
+	return H_MAKE(PRED, (void *)p->ast);
+}
+HParsedToken *act_obj(const HParseResult *p, void *u) {
+	return H_MAKE(OBJ, (void *)p->ast);
+}
+HParsedToken *act_adj(const HParseResult *p, void *u) {
+	return H_MAKE(ADJ, (void *)p->ast);
+}
+HParsedToken *act_advc(const HParseResult *p, void *u) {
+	return H_MAKE(ADVC, (void *)p->ast);
+}
+
+
+/*
+ * grammar
+ */
+
+HParser *
+build_parser(void)
+{
+	/* words */
+	#define W(X)	h_whitespace(h_literal(#X))
+	H_RULE(art,	h_choice(W(a), W(the), NULL));
+	H_RULE(noun,	h_choice(W(cat), W(dog), W(fox), W(tiger), W(lion),
+			    W(bear), W(fence), W(tree), W(car), W(cow), NULL));
+	H_RULE(verb,	h_choice(W(eats), W(jumps), W(falls), NULL));
+	H_ARULE(adj,	h_choice(W(quick), W(slow), W(happy), W(lazy), W(cyan),
+			    W(magenta), W(yellow), W(black), W(brown), NULL));
+	H_RULE(adverb,	h_choice(W(with), W(over), W(after), NULL));
+	#undef W
+
+	/* phrases */
+	H_RULE(nphrase,	h_sequence(art, h_many(adj), noun, NULL));
+
+	/* sentence structure */
+	H_ARULE(subj,	nphrase);
+	H_ARULE(pred,	verb);
+	H_ARULE(obj,	nphrase);
+	H_ARULE(advc,	h_sequence(adverb, nphrase, NULL));
+	H_RULE(sentnc,	h_sequence(subj, pred,
+			    h_optional(obj), h_optional(advc), NULL));
+
+	return sentnc;
+}
+
+
+/*
+ * main routine: read, parse, print
+ *
+ * input e.g.:
+ * "the quick brown fox jumps the fence with a cyan lion"
+ */
+
+#include <stdio.h>
+#include <inttypes.h>
+
+int
+main(int argc, char **argv)
+{
+	uint8_t input[1024];
+	size_t sz;
+	const HParser *parser;
+	const HParseResult *result;
+
+	init();
+	parser = build_parser();
+
+	sz = fread(input, 1, sizeof(input), stdin);
+	if (!feof(stdin)) {
+		fprintf(stderr, "too much input\n");
+		return 1;
+	}
+
+	result = h_parse(parser, input, sz);
+	if (!result) {
+		fprintf(stderr, "no parse\n");
+		return 1;
+	}
+
+        h_pprintln(stdout, result->ast);
+        fprintf(stderr, "consumed %" PRId64 "/%zu bytes.\n",
+	    result->bit_length / 8, sz);
+        return 0;
+}