never executed always true always false

    1 -- Copyright (C) 2018-2024 Jun Zhang <zhangjunphy[at]gmail[dot]com>
    2 --
    3 -- This file is a part of decafc.
    4 --
    5 -- decafc is free software: you can redistribute it and/or modify it under the
    6 -- terms of the MIT (X11) License as described in the LICENSE file.
    7 --
    8 -- decafc is distributed in the hope that it will be useful, but WITHOUT ANY
    9 -- WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
   10 -- FOR A PARTICULAR PURPOSE.  See the X11 license for more details.
   11 
   12 -- Lexer tokens
   13 module Lexer.Token (Token(..)) where
   14 
   15 import Data.Text (Text)
   16 
   17 -- | Lexer tokens.
   18 data Token = Keyword !Text
   19            | Identifier !Text
   20            | CharLiteral !Text
   21            | IntLiteral !Text
   22            | BooleanLiteral !Text
   23            | StringLiteral !Text
   24            | AssignOp
   25            | CompoundAssignOp !Text
   26            | IncrementOp !Text
   27            | ArithmeticOp !Text
   28            | RelationOp !Text
   29            | EquationOp !Text
   30            | ConditionOp !Text
   31            | LCurly
   32            | RCurly
   33            | LParen
   34            | RParen
   35            | LBrack
   36            | RBrack
   37            | Choice
   38            | Colon
   39            | Semicolon
   40            | Comma
   41            | Negate
   42            | EOF
   43            deriving (Eq)
   44 
   45 instance Show Token where
   46   show (Keyword k) = show k
   47   show (Identifier s) = "IDENTIFIER " ++ show s
   48   show (CharLiteral s) = "CHARLITERAL " ++ show s
   49   show (IntLiteral s) = "INTLITERAL " ++ show s
   50   show (BooleanLiteral s) = "BOOLEANLITERAL " ++ show s
   51   show (StringLiteral s) = "STRINGLITERAL " ++ show s
   52   show AssignOp = "="
   53   show (IncrementOp s) = show s
   54   show (CompoundAssignOp s) = show s
   55   show (ArithmeticOp s) = show s
   56   show (RelationOp s) = show s
   57   show (EquationOp s) = show s
   58   show (ConditionOp s) = show s
   59   show LCurly = "{"
   60   show RCurly = "}"
   61   show LParen = "("
   62   show RParen = ")"
   63   show LBrack = "["
   64   show RBrack = "]"
   65   show Choice = "?"
   66   show Colon = ":"
   67   show Semicolon = ";"
   68   show Comma = ","
   69   show Negate = "!"
   70   show EOF = "EOF"