Rework named captures to be array

To comply with the whole reverse replacing

processor/regex.go

@@ -66,6 +66,12 @@ func (p *RegexProcessor) FromLua(L *lua.LState) (interface{}, error) {
 	return modifications, nil
 }
 
+type NamedCapture struct {
+	Name  string
+	Value string
+	Range [2]int
+}
+
 // ProcessContent applies regex replacement with Lua processing
 func (p *RegexProcessor) ProcessContent(content string, pattern string, luaExpr string) (string, int, int, error) {
 	// Handle special pattern modifications
@@ -151,15 +157,21 @@ func (p *RegexProcessor) ProcessContent(content string, pattern string, luaExpr
 		}
 		log.Printf("Captured groups: %v", captures)
 
-		namedCaptures := make(map[string]string)
-		namedCaptureGroups := make(map[string][2]int)
+		// We have to use array to preserve order
+		// Very important for the reconstruction step
+		// Because we must overwrite the values in reverse order
+		// See comments a few dozen lines above for more details
+		namedCaptures := make([]NamedCapture, 0, len(groups)/2)
 		groupNames := compiledPattern.SubexpNames()[1:]
 		for i, name := range groupNames {
 			if name == "" {
 				continue
 			}
-			namedCaptures[name] = captures[i]
-			namedCaptureGroups[name] = [2]int{groups[i*2], groups[i*2+1]}
+			namedCaptures = append(namedCaptures, NamedCapture{
+				Name:  name,
+				Value: captures[i],
+				Range: [2]int{groups[i*2], groups[i*2+1]},
+			})
 		}
 
 		log.Printf("Named captures: %v", namedCaptures)
@@ -170,14 +182,14 @@ func (p *RegexProcessor) ProcessContent(content string, pattern string, luaExpr
 		}
 		log.Println("Lua variables set successfully")
 
-		for name, capture := range namedCaptures {
-			if name == "" {
+		for _, capture := range namedCaptures {
+			if capture.Name == "" {
 				continue
 			}
-			if val, err := strconv.ParseFloat(capture, 64); err == nil {
-				L.SetGlobal(name, lua.LNumber(val))
+			if val, err := strconv.ParseFloat(capture.Value, 64); err == nil {
+				L.SetGlobal(capture.Name, lua.LNumber(val))
 			} else {
-				L.SetGlobal(name, lua.LString(capture))
+				L.SetGlobal(capture.Name, lua.LString(capture.Value))
 			}
 		}
 
@@ -214,13 +226,13 @@ func (p *RegexProcessor) ProcessContent(content string, pattern string, luaExpr
 		}
 
 		for i := len(namedCaptures) - 1; i >= 0; i-- {
-			name := groupNames[i]
-			if name == "" {
+			capture := namedCaptures[i]
+			if capture.Name == "" {
 				continue
 			}
-			groupStart := namedCaptureGroups[name][0] - matchIndices[0]
-			groupEnd := namedCaptureGroups[name][1] - matchIndices[0]
-			luaValue := L.GetGlobal(name).String()
+			groupStart := capture.Range[0] - matchIndices[0]
+			groupEnd := capture.Range[1] - matchIndices[0]
+			luaValue := L.GetGlobal(capture.Name).String()
 			replacement = replacement[:groupStart] + luaValue + replacement[groupEnd:]
 		}