package code.loop.parser;

%%

%char
%public
%type Token

%yylexthrow{
  ParseError
%yylexthrow}

%eofval{
    return (new Token(0, yychar)); 
%eofval}


WHITE_SPACE=([" "\t\b\r])+
DIGIT=[0-9]
ALPHA=[a-zA-Z]
STRING=([\x20\x21\x23-\x7E])*
INT=({DIGIT})+
FLOAT=({DIGIT})+"."({DIGIT})+

PREFIX="$"?{ALPHA}({ALPHA}|{DIGIT}|['_])*
INFIX    = (["~!@#$%^&*+-=<>?./|\:"])+
PREFIXID = ({PREFIX}".")*{PREFIX}
INFIXID  = ({PREFIX}".")*{INFIX}

%%

<YYINITIAL> if { return (new Token(Token.IF, yychar+1)); }
<YYINITIAL> then { return (new Token(Token.THEN, yychar+1)); }
<YYINITIAL> else { return (new Token(Token.ELSE, yychar+1)); }
<YYINITIAL> where { return (new Token(Token.WHERE, yychar+1)); }
<YYINITIAL> free { return (new Token(Token.FREE, yychar+1)); }
<YYINITIAL> "-" { return (new Token(Token.MINUS, yychar+1)); }


<YYINITIAL> ".." { return (new Token(Token.DOUBLEDOT, yychar+1)); }
<YYINITIAL> "," { return (new Token(Token.COMMA, yychar+1)); }
<YYINITIAL> "(" { return (new Token(Token.LPAREN, yychar+1)); }
<YYINITIAL> ")" { return (new Token(Token.RPAREN, yychar+1)); }
<YYINITIAL> "[" { return (new Token(Token.LSQBRA, yychar+1)); }
<YYINITIAL> "]" { return (new Token(Token.RSQBRA, yychar+1)); }
<YYINITIAL> "`" { return (new Token(Token.BACKQUOTE, yychar+1)); }

<YYINITIAL> {WHITE_SPACE} {}

<YYINITIAL> {INT} {
  try {
    if(Integer.parseInt(yytext()) < Integer.MAX_VALUE) 
      return (new Token(Token.INTEGER, yychar+1, Integer.valueOf(yytext())));
  } catch(Exception e) {
      throw new ParseError("Error at char "+(yychar+1)+": Integer value out of range!");
  }
}


<YYINITIAL> {FLOAT} {
  try {
    if(Float.parseFloat(yytext()) < Float.MAX_VALUE) 
      return (new Token(Token.FLOAT, yychar+1, Float.valueOf(yytext())));
  } catch(Exception e) {
      throw new ParseError("Error at char "+(yychar+1)+": Float value out of range!");
  }
}

<YYINITIAL> {PREFIXID} {
  try {
    if(yytext().length() < 255)
      return (new Token(Token.PREFIXID, yychar+1, yytext()));
    
    else {
      throw new ParseError("Error at char "+(yychar+1)+": Identifier length out oof range!");
    }
  }catch(Exception e) { 
    throw new ParseError("Exception error at char "+(yychar+1));
  }
} 

<YYINITIAL> {INFIXID} {
  try {
    if(yytext().length() < 255)
      return (new Token(Token.INFIXID, yychar+1, yytext()));
    
    else {
      throw new ParseError("Error at char "+(yychar+1)+": Identifier length out oof range!");
    }
  }catch(Exception e) { 
    throw new ParseError("Exception error at char "+(yychar+1));
  }
} 


<YYINITIAL> \"{STRING}\"  {
  try {
    String str =  yytext().substring(1,yytext().length() - 1);	
    if(str.length() <= 255)
      return (new Token(Token.STRING, yychar+1, str));
    else {
      throw new ParseError("Error at char "+(yychar+1)+": String length out of range!");
    } 
  }catch(Exception e) {
    throw new ParseError("Exception error at char "+(yychar+1));
  }
}

<YYINITIAL> \"{STRING} {
  throw new ParseError("Error at char "+(yychar+1)+": Unterminated string!");
}

<YYINITIAL> \'{ALPHA}\'  {
      return (new Token(Token.CHAR, yychar+1, new Character(yytext().charAt(1))));
}

<YYINITIAL> \'{ALPHA} {
  throw new ParseError("Error at char "+(yychar+1)+": Unterminated character!");
}


<YYINITIAL> . { 
  throw new ParseError("Error at char "+(yychar+1)+": Illegal input"); 
}