diff --git a/src/tokens.rs b/src/tokens.rs
index f9a91ea..de10921 100644
--- a/src/tokens.rs
+++ b/src/tokens.rs
@@ -53,3 +53,17 @@ pub struct Token {
     pub lexeme: String,
     pub line: usize,
 }
+
+impl Token {
+    /// Check whether a token corresponds to a litteral value.
+    pub fn is_litteral(&self) -> bool {
+        match self.token_type {
+            TokenType::True
+            | TokenType::False
+            | TokenType::Nil
+            | TokenType::String(_)
+            | TokenType::Number(_) => true,
+            _ => false,
+        }
+    }
+}