From db1fc26c82065656e558022e59f886b70ed7d78d Mon Sep 17 00:00:00 2001
From: "Sven M. Hallberg" <pesco@khjk.org>
Date: Mon, 25 Nov 2019 12:57:48 +0100
Subject: [PATCH] add examples/ttuser - show custom tokens/pprint
---
examples/SConscript | 3 +-
examples/ttuser.c | 140 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 142 insertions(+), 1 deletion(-)
create mode 100644 examples/ttuser.c
diff --git a/examples/SConscript b/examples/SConscript
index b34b85a1..8504b4bb 100644
--- a/examples/SConscript
+++ b/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])
\ No newline at end of file
+env.Alias("examples", [dns, ttuser, base64, base64_sem1, base64_sem2, ties])
diff --git a/examples/ttuser.c b/examples/ttuser.c
new file mode 100644
index 00000000..4e83356c
--- /dev/null
+++ b/examples/ttuser.c
@@ -0,0 +1,140 @@
+/*
+ * 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;
+}
--
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