internal/rosa/azalea: simplified delimiter insertion function

internal/rosa/azalea/azalea.go

@@ -303,7 +303,7 @@ func (ScanError) Error() string {
 
 // Parse parses expressions from r.
 func Parse(r io.Reader) (e []any, err error) {
-	r, err = insertSemicolons(r)
+	r, err = insertDelimiters(r)
 	var p parser
 	p.s.Init(r)
 
@@ -349,7 +349,7 @@ func isIdentRune(ch rune, i int) bool {
 	}
 	return ch > 0 && ch < rune(len(idents)) && idents[ch]
 }
-func insertSemicolons(r io.Reader) (io.Reader, error) {
+func insertDelimiters(r io.Reader) (io.Reader, error) {
 	var s scanner.Scanner
 	s.Init(r)
 	s.Mode = scanner.ScanIdents |
@@ -362,94 +362,60 @@ func insertSemicolons(r io.Reader) (io.Reader, error) {
 	s.IsIdentRune = isIdentRune
 
 	var buf strings.Builder
-	nlsemi := false
-	nlcomma := false
-	b := new(RuneStack)
+	nldelim := false
+	b := new(runeStack)
 
-	tok := s.Scan()
-	for tok != scanner.EOF {
+	for tok := s.Scan(); tok != scanner.EOF; tok = s.Scan() {
 		switch tok {
-		case '\n':
-			if b.Peek() == '{' && nlsemi {
-				buf.WriteRune(';')
-				nlsemi = false
-			}
-			if b.Peek() == '[' && nlcomma {
-				buf.WriteRune(',')
-				nlcomma = false
-			}
-		case ';':
-			buf.WriteRune(tok)
-			nlsemi = false
-		case ',':
-			buf.WriteRune(tok)
-			nlcomma = false
 		case '{', '[':
-			nlsemi = false
-			nlcomma = false
-			buf.WriteRune(tok)
-			b.Push(tok)
-		case '}', ']':
-			r := b.Pop()
-			if r == '{' {
-				if nlsemi {
-					buf.WriteRune(';')
-				}
-				nlcomma = true
-				nlsemi = true
-			}
-			if r == '[' {
-				if nlcomma {
-					buf.WriteRune(',')
-				}
-				nlsemi = true
+			nldelim = false
+			if tok == '{' {
+				b.Push(';')
+			} else {
+				b.Push(',')
 			}
 			buf.WriteRune(tok)
-		case '+', ':', '=':
-			buf.WriteRune(tok)
-			nlsemi = false
-			nlcomma = false
 		case scanner.String, scanner.RawString, scanner.Int, scanner.Ident:
 			buf.WriteString(s.TokenText())
-			if b.Peek() == '{' {
-				nlsemi = true
-			} else if b.Peek() == '[' {
-				nlcomma = true
+			nldelim = true
+		case '+', ':', '=', ',', ';':
+			nldelim = false
+			buf.WriteRune(tok)
+		case '\n':
+			if nldelim {
+				buf.WriteRune(b.Peek())
+				nldelim = false
 			}
+			buf.WriteRune(tok)
+		case '}', ']':
+			if nldelim {
+				buf.WriteRune(b.Peek())
+			}
+			b.Pop()
+			nldelim = true
+			buf.WriteRune(tok)
 		default:
-			buf.WriteString(s.TokenText())
+			buf.WriteRune(tok)
 		}
-
-		tok = s.Scan()
 	}
 	return strings.NewReader(buf.String()), nil
 }
 
-type Stack[T any] interface {
-	Push(T)
-	Pop() T
-	Peek() T
-	Length() int
-}
-type RuneStack struct {
+type runeStack struct {
 	arr []rune
-	Stack[rune]
 }
 
-func (s *RuneStack) Push(r rune) {
+func (s *runeStack) Push(r rune) {
 	s.arr = append(s.arr, r)
 }
 
-func (s *RuneStack) String() string {
-	return string(s.arr)
-}
-func (s *RuneStack) Peek() rune {
+func (s *runeStack) Peek() rune {
 	if s.Length() > 0 {
 		return s.arr[s.Length()-1]
 	}
-	return 0
+	return '\n'
 }
-func (s *RuneStack) Pop() rune {
+func (s *runeStack) Pop() rune {
 	v := s.Peek()
 	if s.Length() > 1 {
 		s.arr = s.arr[:s.Length()-1]
@@ -458,6 +424,6 @@ func (s *RuneStack) Pop() rune {
 	}
 	return v
 }
-func (s *RuneStack) Length() int {
+func (s *runeStack) Length() int {
 	return len(s.arr)
 }