Stop using lists to represent args

src/Lexer.hs

@@ -13,6 +13,8 @@ data LToken
   | LIntegerLiteral Int
   | LStringLiteral String
   | LAssign
+  | LColon
+  | LBackslash
   | LOpenParen
   | LCloseParen
   | LOpenBracket
@@ -48,6 +50,12 @@ stringLiteral = do
 assign :: Lexer LToken
 assign = char '=' *> pure LAssign
 
+colon :: Lexer LToken
+colon = char ':' *> pure LColon
+
+backslash :: Lexer LToken
+backslash = char '\\' *> pure LBackslash
+
 openParen :: Lexer LToken
 openParen = char '(' *> pure LOpenParen
 
@@ -73,6 +81,8 @@ saplingLexer = many (sc *> choice
   , try integerLiteral
   , try stringLiteral
   , assign
+  , colon
+  , backslash
   , openParen
   , closeParen
   , openBracket