Keep adjacent replace_all matches reachable

Author: mgomes

vibes/builtins.go

@@ -552,25 +552,46 @@ func regexReplaceAllWithLimit(re *regexp.Regexp, text string, replacement string
 }
 
 func nextRegexReplaceAllSubmatchIndex(re *regexp.Regexp, text string, start int) ([]int, bool) {
-	windowStart := start
-	if windowStart > 0 {
-		windowStart--
+	loc := re.FindStringSubmatchIndex(text[start:])
+	if loc == nil {
+		return nil, false
+	}
+	direct := offsetRegexSubmatchIndex(loc, start)
+	if start == 0 || direct[0] > start {
+		return direct, true
 	}
+
+	windowStart := start - 1
 	locs := re.FindAllStringSubmatchIndex(text[windowStart:], 2)
-	for _, loc := range locs {
-		absStart := loc[0] + windowStart
-		if absStart < start {
+	if len(locs) == 0 {
+		return nil, false
+	}
+
+	first := offsetRegexSubmatchIndex(locs[0], windowStart)
+	if first[0] >= start {
+		return first, true
+	}
+	if first[1] > start {
+		return direct, true
+	}
+	if len(locs) < 2 {
+		return nil, false
+	}
+	second := offsetRegexSubmatchIndex(locs[1], windowStart)
+	if second[0] >= start {
+		return second, true
+	}
+	return nil, false
+}
+
+func offsetRegexSubmatchIndex(loc []int, offset int) []int {
+	abs := make([]int, len(loc))
+	for i, index := range loc {
+		if index < 0 {
+			abs[i] = -1
 			continue
 		}
-		abs := make([]int, len(loc))
-		for i, index := range loc {
-			if index < 0 {
-				abs[i] = -1
-				continue
-			}
-			abs[i] = index + windowStart
-		}
-		return abs, true
+		abs[i] = index + offset
 	}
-	return nil, false
+	return abs
 }

vibes/runtime_test.go

@@ -1954,6 +1954,7 @@ func TestRegexBuiltins(t *testing.T) {
 	        match_empty: Regex.match("^", "ID-12"),
 	        replace_one: Regex.replace("ID-12 ID-34", "ID-[0-9]+", "X"),
 	        replace_all: Regex.replace_all("ID-12 ID-34", "ID-[0-9]+", "X"),
+	        replace_all_adjacent: Regex.replace_all("aaaa", "aa", "X"),
 	        replace_all_anchor: Regex.replace_all("abc", "^", "X"),
 	        replace_all_boundary: Regex.replace_all("ab", "\\b", "X"),
 	        replace_all_abutting_empty: Regex.replace_all("aa", "aa|", "X"),
@@ -1987,6 +1988,9 @@ func TestRegexBuiltins(t *testing.T) {
 	if !out["replace_all"].Equal(NewString("X X")) {
 		t.Fatalf("replace_all mismatch: %v", out["replace_all"])
 	}
+	if !out["replace_all_adjacent"].Equal(NewString("XX")) {
+		t.Fatalf("replace_all_adjacent mismatch: %v", out["replace_all_adjacent"])
+	}
 	if !out["replace_all_anchor"].Equal(NewString("Xabc")) {
 		t.Fatalf("replace_all_anchor mismatch: %v", out["replace_all_anchor"])
 	}