diff --git a/compiler/lexer.py b/compiler/lexer.py
index 4c9feba..603b429 100644
--- a/compiler/lexer.py
+++ b/compiler/lexer.py
@@ -39,7 +39,7 @@ class Tokens(enum.Enum):
 
     KwLet = re.compile(r"\blet\b")
 
-    Identifier = re.compile(r"[a-zA-Z_][a-zA-Z_0-9]*")
+    Identifier = re.compile(r"\b[a-zA-Z_][a-zA-Z_0-9]*\b")
 
     Equal = re.compile(r"=")
     Colon = re.compile(r":")