Implement special character escaping

lib/parser.c

@@ -15,6 +15,7 @@ static bool is_special(char c)
 	switch (c) {
 	case '|':
 	case '.':
+	case '\\':
 		return true;
 	default:
 		return false;
@@ -26,6 +27,9 @@ static int parse_literal(const char *input, int rem, char *out)
 	if (rem > 0 && !is_special(input[0])) {
 		*out = input[0];
 		return 1;
+	} else if (rem > 1 && '\\' == input[0]) {
+		*out = input[1];
+		return 2;
 	} else {
 		return -1;
 	}

tests/parser_tests.c

@@ -97,6 +97,34 @@ static void dot_is_parsed_as_unquantified_wildcard_term(void)
 	regex_free_children(&r);
 }
 
+static void backslash_dot_is_parsed_as_unquantified_literal(void)
+{
+	regex_t r = { 0 };
+	const int result = PARSE_REGEX_STRING("\\.", &r);
+	ASSERT_NE(-1, result);
+
+	ASSERT_EQ(1, r.sequence.len);
+	ASSERT_EQ(QUANTIFIER_NONE, r.sequence.contents[0].quantifier);
+	ASSERT_EQ(TERM_TYPE_LITERAL, r.sequence.contents[0].type);
+	ASSERT_EQ('.', r.sequence.contents[0].literal);
+
+	regex_free_children(&r);
+}
+
+static void backslash_backslash_is_parsed_as_unquantified_literal(void)
+{
+	regex_t r = { 0 };
+	const int result = PARSE_REGEX_STRING("\\\\", &r);
+	ASSERT_NE(-1, result);
+
+	ASSERT_EQ(1, r.sequence.len);
+	ASSERT_EQ(QUANTIFIER_NONE, r.sequence.contents[0].quantifier);
+	ASSERT_EQ(TERM_TYPE_LITERAL, r.sequence.contents[0].type);
+	ASSERT_EQ('\\', r.sequence.contents[0].literal);
+
+	regex_free_children(&r);
+}
+
 int main(void)
 {
 	TESTING_BEGIN();
@@ -107,5 +135,7 @@ int main(void)
 	b_is_parsed_as_unquantified_literal();
 	abc_is_parsed_as_sequence_of_unquantified_literals();
 	dot_is_parsed_as_unquantified_wildcard_term();
+	backslash_dot_is_parsed_as_unquantified_literal();
+	backslash_backslash_is_parsed_as_unquantified_literal();
 	return TESTING_END();
 }