diff --git a/backend_wat.go b/backend_wat.go
index 8d88293..291a5c5 100644
--- a/backend_wat.go
+++ b/backend_wat.go
@@ -358,7 +358,6 @@ func (c *Compiler) compileStatementWAT(stmt Statement, block *Block) (string, er
 			return "", err
 		}
 
-		// TODO: upcast to return type for non-primitive types
 		return wat + "return\n", nil
 	case Statement_DeclareLocalVariable:
 		dlv := stmt.Value.(DeclareLocalVariableStatement)
diff --git a/lexer.go b/lexer.go
index e2b1778..5b43fc4 100644
--- a/lexer.go
+++ b/lexer.go
@@ -38,7 +38,7 @@ const (
 
 type Separator uint32
 
-var Separators []rune = []rune{'(', ')', '{', '}', '[', ']', ';', ',', '.'}
+var Separators []string = []string{"(", ")", "{", "}", "[", "]", ";", ",", "."}
 
 const (
 	Separator_OpenParen Separator = iota
@@ -145,6 +145,42 @@ func (l *Lexer) tryOperator() Operator {
 	return foundOp
 }
 
+func (l *Lexer) trySeparator() Separator {
+	var foundSep Separator = InvalidValue
+	var foundSepLen int = 0
+
+	str := string(l.Runes)
+	for i, separator := range Separators {
+		separatorLen := len([]rune(separator))
+		if separatorLen <= foundSepLen {
+			continue
+		}
+
+		if strings.HasPrefix(str, separator) {
+			foundSep = Separator(i)
+			foundSepLen = len([]rune(separator))
+		}
+	}
+
+	for i := 0; i < foundSepLen; i++ {
+		l.nextRune()
+	}
+
+	return foundSep
+}
+
+func (l *Lexer) hasNext(choices ...string) bool {
+	str := string(l.Runes)
+
+	for _, c := range choices {
+		if strings.HasPrefix(str, c) {
+			return true
+		}
+	}
+
+	return false
+}
+
 func (l *Lexer) nextRune() *rune {
 	if len(l.Runes) == 0 {
 		return nil
@@ -227,10 +263,15 @@ func (l *Lexer) nextToken() (*LexToken, error) {
 		return &LexToken{Type: Type_Operator, Position: TokenPosition{SourceFile: l.SourceFile, Position: l.LastTokenPosition}, Value: op}, nil
 	}
 
+	sep := l.trySeparator()
+	if sep != InvalidValue {
+		return &LexToken{Type: Type_Separator, Position: TokenPosition{SourceFile: l.SourceFile, Position: l.LastTokenPosition}, Value: sep}, nil
+	}
+
 	token := ""
 	for {
 		r := l.peekRune()
-		if r == nil || slices.Contains(Whitespace, *r) || slices.Contains(Separators, *r) {
+		if r == nil || slices.Contains(Whitespace, *r) || l.hasNext(Separators...) || l.hasNext(Operators...) {
 			break
 		}
 
@@ -278,12 +319,6 @@ func (l *Lexer) nextToken() (*LexToken, error) {
 		return &LexToken{Type: Type_Literal, Position: TokenPosition{SourceFile: l.SourceFile, Position: l.LastTokenPosition}, Value: Literal{Type: Literal_Number, Primitive: numberType, Value: number}}, nil
 	}
 
-	if len(runes) == 1 {
-		if idx := slices.Index(Separators, runes[0]); idx != -1 {
-			return &LexToken{Type: Type_Separator, Position: TokenPosition{SourceFile: l.SourceFile, Position: l.LastTokenPosition}, Value: Separator(idx)}, nil
-		}
-	}
-
 	if idx := slices.Index(Keywords, token); idx != -1 {
 		return &LexToken{Type: Type_Keyword, Position: TokenPosition{SourceFile: l.SourceFile, Position: l.LastTokenPosition}, Value: Keyword(idx)}, nil
 	}
diff --git a/parser.go b/parser.go
index 1f2c346..172f0cb 100644
--- a/parser.go
+++ b/parser.go
@@ -166,7 +166,7 @@ type Local struct {
 }
 
 type Block struct {
-	Parent     *Block // TODO: implement
+	Parent     *Block
 	Statements []Statement
 	Locals     map[string]Local
 }