diff --git a/src/Language/Bergamot/Parser.purs b/src/Language/Bergamot/Parser.purs
index b18d4fe..88f29c4 100644
--- a/src/Language/Bergamot/Parser.purs
+++ b/src/Language/Bergamot/Parser.purs
@@ -26,7 +26,7 @@ whitespace :: Parser String Unit
 whitespace = void $ many space
 
 identifier :: Parser String String
-identifier = (charsToString <$> many1 (letter <|> digit <|> char '_')) <* whitespace
+identifier = (charsToString <$> many1 (letter <|> digit <|> char '_' <|> char '\\')) <* whitespace
 
 expr :: Parser String (Expr Metavariable)
 expr = (defer $ \_ -> atom) <|> (defer $ \_ -> metavariable)