Allow keywords as variables (#19)

src/SqlSquare/Parser.purs

@@ -107,6 +107,11 @@ keyword s = PC.try $ token >>= case _ of
   Kw ss | S.toLower s == S.toLower ss → pure s
   _ → P.fail $ "Token is not a keyword " <> s
 
+anyKeyword ∷ ∀ m. Monad m ⇒ P.ParserT (Array Token) m String
+anyKeyword = PC.try $ token >>= case _ of
+  Kw s → pure s
+  _ → P.fail "Token is not a keyword"
+
 match ∷ ∀ m. Monad m ⇒ Token → P.ParserT (Array Token) m Token
 match = whenTok ∘ eq
 
@@ -467,7 +472,7 @@ variable
   ⇒ P.ParserT (Array Token) m t
 variable = PC.try do
   operator ":"
-  s ← ident
+  s ← ident <|> anyKeyword
   pure $ embed $ Sig.Vari s
 
 literal

test/src/Parse.purs

@@ -39,6 +39,7 @@ select 12
 """
   , """import foo; select * from `/test`"""
   , """create function foo(:bar) begin :bar + 2 end; select * from `/test` where foo = foo(42)"""
+  , """select :where"""
   ]
 
 testSuite ∷ ∀ e. TestSuite (testOutput ∷ Console.TESTOUTPUT | e)