From 77e1a77e02aef7674b3301da2755b09b6c3641a5 Mon Sep 17 00:00:00 2001
From: Camden Dixie O'Brien <cdo@wip.sh>
Date: Sun, 3 Nov 2024 11:59:56 +0000
Subject: [PATCH] Support wildcards in construct

---
 lib/construct.c         | 10 ++++++++--
 tests/construct_tests.c | 26 ++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/lib/construct.c b/lib/construct.c
index 4332c8f..f0b2417 100644
--- a/lib/construct.c
+++ b/lib/construct.c
@@ -164,6 +164,13 @@ static void construct_class(fsa_t *out, const regex_class_t *class)
 	}
 }
 
+static void construct_wildcard(fsa_t *out)
+{
+	construct_base(out);
+	for (int i = 0; i < CHAR_COUNT; ++i)
+		fsa_add_rule(out, out->initial, 0, i);
+}
+
 static void construct_term(const regex_term_t *term, fsa_t *out)
 {
 	switch (term->type) {
@@ -179,9 +186,8 @@ static void construct_term(const regex_term_t *term, fsa_t *out)
 	case REGEX_TERM_CLASS:
 		construct_class(out, &term->class);
 		break;
-
 	case REGEX_TERM_WILDCARD:
-		assert(false);
+		construct_wildcard(out);
 		break;
 	}
 
diff --git a/tests/construct_tests.c b/tests/construct_tests.c
index 20f7f87..155330d 100644
--- a/tests/construct_tests.c
+++ b/tests/construct_tests.c
@@ -53,6 +53,31 @@ static void test_empty_expression(void)
 	fsa_free(&fsa);
 }
 
+static void test_wildcard(void)
+{
+	regex_term_t *terms = malloc(1 * sizeof(regex_term_t));
+	terms[0].quantifier = REGEX_QUANTIFIER_NONE;
+	terms[0].type = REGEX_TERM_WILDCARD;
+	regex_sequence_t *alternatives = malloc(1 * sizeof(regex_sequence_t));
+	alternatives[0].count = alternatives[0].capacity = 1;
+	alternatives[0].contents = terms;
+	const regex_t regex
+	    = { .count = 1, .capacity = 1, .contents = alternatives };
+
+	fsa_t fsa;
+	construct_nfa(&regex, &fsa);
+
+	ASSERT_TRUE(accepts(&fsa, "a"));
+	ASSERT_TRUE(accepts(&fsa, "b"));
+	ASSERT_TRUE(accepts(&fsa, "c"));
+	ASSERT_TRUE(accepts(&fsa, "d"));
+	ASSERT_FALSE(accepts(&fsa, ""));
+	ASSERT_FALSE(accepts(&fsa, "aa"));
+
+	regex_free(&regex);
+	fsa_free(&fsa);
+}
+
 static void test_literal_expression(void)
 {
 	regex_term_t *terms = malloc(1 * sizeof(regex_term_t));
@@ -386,6 +411,7 @@ int main(void)
 	// Base cases
 	test_empty_expression();
 	test_literal_expression();
+	test_wildcard();
 	test_sequence();
 	test_union();
 	test_star();