diff --git a/lib/syntax/parser.mly b/lib/syntax/parser.mly
index 1c49e29..a511c13 100644
--- a/lib/syntax/parser.mly
+++ b/lib/syntax/parser.mly
@@ -54,6 +54,9 @@ infixexp:
   | e1 = infixexp; op = Binop; e2 = singleexp { infix_app e1 op e2 }
 
 singleexp:
+  | "nil" { Literal Nil }
+  | "true" { Literal True }
+  | "false" { Literal False }
   | i = Int { Literal (Int i) }
   | p = path { Path p }
   | f = path; a = args { Call (f, a) }