diff --git a/lexer/keyword.py b/lexer/keyword.py
index 2ab3f45..e5c4b64 100644
--- a/lexer/keyword.py
+++ b/lexer/keyword.py
@@ -3,7 +3,9 @@ from lexer.token import TokenType
 KEYWORDS: dict[str, TokenType] = {
     "type": TokenType.TYPE,
     "op": TokenType.OP,
-    "constraint": TokenType.CONSTRAINT,
+    "predicate": TokenType.PREDICATE,
+    "extend": TokenType.EXTEND,
+    "where": TokenType.WHERE,
     "true": TokenType.TRUE,
     "false": TokenType.FALSE,
     "none": TokenType.NONE,
diff --git a/lexer/midas.py b/lexer/midas.py
index b366f09..be3bfdf 100644
--- a/lexer/midas.py
+++ b/lexer/midas.py
@@ -31,30 +31,32 @@ class MidasLexer(Lexer):
                 self.add_token(
                     TokenType.EQUAL_EQUAL if self.match("=") else TokenType.EQUAL
                 )
-            case "!":
-                if self.match("="):
-                    self.add_token(TokenType.BANG_EQUAL)
-                else:
-                    self.error("Unexpected single bang. Did you mean '!=' ?")
+            case "!" if self.match("="):
+                self.add_token(TokenType.BANG_EQUAL)
             case ":":
                 self.add_token(TokenType.COLON)
-            case ",":
-                self.add_token(TokenType.COMMA)
+            case ".":
+                self.add_token(TokenType.DOT)
+            case "&":
+                self.add_token(TokenType.AND)
+            case "?":
+                self.add_token(TokenType.QMARK)
+            # case ",":
+            #     self.add_token(TokenType.COMMA)
             case "_":
                 self.add_token(TokenType.UNDERSCORE)
-            case "+":
-                self.add_token(TokenType.PLUS)
+            case "-" if self.match(">"):
+                self.add_token(TokenType.ARROW)
+            # case "+":
+            #     self.add_token(TokenType.PLUS)
             case "-":
                 self.add_token(TokenType.MINUS)
-            case "*":
-                self.add_token(TokenType.STAR)
-            case "/":
-                if self.match("/"):
-                    self.scan_comment()
-                elif self.match("*"):
-                    self.scan_comment_multiline()
-                else:
-                    self.add_token(TokenType.SLASH)
+            # case "*":
+            #     self.add_token(TokenType.STAR)
+            case "/" if self.match("/"):
+                self.scan_comment()
+            case "/" if self.match("*"):
+                self.scan_comment_multiline()
             case "\n":
                 self.add_token(TokenType.NEWLINE)
             case " " | "\r" | "\t":
diff --git a/lexer/token.py b/lexer/token.py
index 70a7a1b..1097493 100644
--- a/lexer/token.py
+++ b/lexer/token.py
@@ -14,14 +14,18 @@ class TokenType(Enum):
     LEFT_BRACE = auto()
     RIGHT_BRACE = auto()
     COLON = auto()
-    COMMA = auto()
+    # COMMA = auto()
     UNDERSCORE = auto()
+    ARROW = auto()
+    AND = auto()
+    QMARK = auto()
+    DOT = auto()
 
     # Operators
-    PLUS = auto()
+    # PLUS = auto()
     MINUS = auto()
-    STAR = auto()
-    SLASH = auto()
+    # STAR = auto()
+    # SLASH = auto()
     GREATER = auto()
     GREATER_EQUAL = auto()
     LESS = auto()
@@ -40,7 +44,9 @@ class TokenType(Enum):
     # Keywords
     TYPE = auto()
     OP = auto()
-    CONSTRAINT = auto()
+    PREDICATE = auto()
+    EXTEND = auto()
+    WHERE = auto()
 
     # Misc
     COMMENT = auto()