regex error reporting

3 files changed, 42 insertions, 9 deletions

diff --git a/main.c b/main.c
index a1281a9..a6caab0 100644
--- a/main.c
+++ b/main.c
@@ -531,8 +531,9 @@ done:;
 int search_next_regex(TxtLoc l, Str src, TxtLoc *out) {
 	RegEx re = { 0 };
 	ReSearch s = { 0 };
-	if (re_comp_ex(&re, src, &e.scratch, &e.scratch, RE_COMP_NO_GROUPS)) {
-		/* TODO: report parse error */
+	int err = re_comp_ex(&re, src, &e.scratch, &e.scratch, RE_COMP_NO_GROUPS);
+	if (err) {
+		e.msg = str_printf(&e.scratch, "Regex error: %s", re_comp_strerror(err));
 		return 0;
 	}
 	TxtLoc t = l;
@@ -561,8 +562,9 @@ search_from_start:
 int search_prev_regex(TxtLoc start, Str src, TxtLoc *out) {
 	RegEx re = { 0 };
 	ReSearch s = { 0 };
-	if (re_comp_ex(&re, src, &e.scratch, &e.scratch, RE_COMP_NO_GROUPS)) {
-		/* TODO: report parse error */
+	int err = re_comp_ex(&re, src, &e.scratch, &e.scratch, RE_COMP_NO_GROUPS);
+	if (err) {
+		e.msg = str_printf(&e.scratch, "Regex error: %s", re_comp_strerror(err));
 		return 0;
 	}
 	int match_found = 0;
@@ -1251,4 +1253,4 @@ int main(int argc, const char **argv) {
 	vui_fini();
 	arena_free(&e.scratch);
 	return 0;
-}
\ No newline at end of file
+}
diff --git a/regex.c b/regex.c
index 6a362e4..88f926e 100644
--- a/regex.c
+++ b/regex.c
@@ -33,6 +33,7 @@ typedef struct {
 	Arena *perm, *scratch;
 	DYNARR(u32) lbl;
 	ReCompFlags flags;
+	ReCompErr err;
 	Str s;
 	int i;
 } ReParser;
@@ -90,7 +91,10 @@ ReNode *re_parse_group(ReParser *s) {
 	/* TODO */
 	skip(s, 1);
 	ReNode *n = re_new_node(s, N_GROUP, re_parse_expr(s), NULL);
-	if (ch(s) != ')') FAIL_WITH_MSG("expected )");
+	if (ch(s) != ')') {
+		s->err = RE_COMP_ENORPAREN;
+		return NULL;
+	}
 	skip(s, 1);
 	return n;
 }
@@ -177,7 +181,7 @@ ReNode *re_parse_atom(ReParser *s) {
 	} break;
 	case 0:
 		/* should never happen? */
-		FAIL_WITH_MSG("atom parsed at end");
+		s->err = RE_COMP_EEOF;
 		return NULL;
 	default: {
 		ReNode *n = re_new_node_char(s, ch(s));
@@ -586,14 +590,33 @@ int re_comp_ex(RegEx *re, Str src, Arena *perm, Arena *scratch, ReCompFlags flag
 		.perm = perm,
 		.scratch = scratch,
 		.s = src,
-		.flags = flags
+		.flags = flags,
+		.err = RE_COMP_ENONE
 	};
 	ReNode *n = re_parse_expr(&s);
+	if (!s.err) {
+		if (s.s.n > 0 && s.s.s[s.s.n - 1] == ')') {
+			s.err = RE_COMP_ENOLPAREN;
+		}
+	}
 
 	if (re_comp_node(&s, n)) return -1;
 	if (re_comp_fin(&s)) return -1;
 
-	return 0;
+	return s.err;
+}
+
+const char *re_comp_strerror(ReCompErr err) {
+	switch (err) {
+	case RE_COMP_ENONE:
+		return "success";
+	case RE_COMP_ENORPAREN:
+		return "no closing )";
+	case RE_COMP_ENOLPAREN:
+		return "no opening (";
+	case RE_COMP_EEOF:
+		return "unexpected end of pattern";
+	}
 }
 
 int re_comp(RegEx *re, Str src, Arena *perm, Arena *scratch) {
diff --git a/regex.h b/regex.h
index b6ee9c7..c21c708 100644
--- a/regex.h
+++ b/regex.h
@@ -111,8 +111,16 @@ typedef enum {
 	RE_COMP_NO_GROUPS = 1
 } ReCompFlags;
 
+typedef enum {
+	RE_COMP_ENONE,
+	RE_COMP_ENORPAREN,
+	RE_COMP_ENOLPAREN,
+	RE_COMP_EEOF,
+} ReCompErr;
+
 int re_comp(RegEx *re, Str src, Arena *perm, Arena *scratch);
 int re_comp_ex(RegEx *re, Str src, Arena *perm, Arena *scratch, ReCompFlags flags);
+const char *re_comp_strerror(ReCompErr err);
 
 void re_search_start(ReSearch *s, RegEx *re, Arena *a);
 void re_search_chunk(ReSearch *s, const char *buf, size_t n);