/++
  Author: Aziz Köksal
  License: GPL2
+/
module Token;

struct Position
{
  size_t loc;
  size_t col;
}

enum TOK
{
  Identifier,
  Comment,
  String,
  Character,
  Number,

  // Brackets
  LParen,
  RParen,
  LBracket,
  RBracket,
  LBrace,
  RBrace,

  Dot, Slice, Ellipses,

  // Floating point operators
  Unordered,
  UorE,
  UorG,
  UorGorE,
  UorL,
  UorLorE,
  LorEorG,
  LorG,

  // Normal operators
  Assign, Equal, NotEqual, Not,
  LessEqual, LessThan,
  LShiftAssign, LShift,
  OrAssign, OrLogical, OrBinary,
  AndAssign, AndLogical, AndBinary,
  PlusAssign, PlusPlus, Plus,
  MinusAssign, MinusMinus, Minus,
  DivAssign, Div,
  MulAssign, Mul,
  ModAssign, Mod,
  XorAssign, Xor,
  CatAssign, Catenate,

  Tilde,
  Colon,
  Semicolon,
  Question,
  Comma,
  Dollar,

  /* Keywords:
     NB.: Token.isKeyword() depends on this list being contiguous.
  */
  Abstract,Alias,Align,Asm,Assert,Auto,Body,
  Bool,Break,Byte,Case,Cast,Catch,Cdouble,
  Cent,Cfloat,Char,Class,Const,Continue,Creal,
  Dchar,Debug,Default,Delegate,Delete,Deprecated,Do,
  Double,Else,Enum,Export,Extern,False,Final,
  Finally,Float,For,Foreach,Foreach_reverse,Function,Goto,
  Idouble,If,Ifloat,Import,In,Inout,Int,
  Interface,Invariant,Ireal,Is,Lazy,Long,Macro,
  Mixin,Module,New,Null,Out,Override,Package,
  Pragma,Private,Protected,Public,Real,Ref,Return,
  Scope,Short,Static,Struct,Super,Switch,Synchronized,
  Template,This,Throw,True,Try,Typedef,Typeid,
  Typeof,Ubyte,Ucent,Uint,Ulong,Union,Unittest,
  Ushort,Version,Void,Volatile,Wchar,While,With,

  EOF
}

alias TOK.Abstract KeywordsBegin;
alias TOK.With KeywordsEnd;

struct Token
{
  TOK type;
  Position pos;

  char* start;
  char* end;

  union
  {
    struct
    {
      string str;
      char pf;
    }
    dchar chr;
    uint _uint;
    float f;
    double d;
  }

  string span()
  {
    assert(start && end);
    return start[0 .. end - start];
  }

  bool isKeyword()
  {
    if (KeywordsBegin <= type && type <= KeywordsEnd)
      return true;
    return false;
  }
}