/*
 * Copyright (C) 2005 Sara di Gregorio  <puellula@gmail.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/


header { package ruby; }  // l'header indica quello che si deve scrivere come  
                          // intestazione dei file che ANTLR crea automaticamente
/**
 * PARSER    
 **/
class P extends Parser;

options {
	k = 6; // pone a 6 il lookahead di token
        buildAST = true;
}

imaginaryTokenDefinition:
  PROGRAM;

// inzio di un programma ruby
program : ( classe | statement)* {#program = #(#[PROGRAM, "PROGRAM"], #program);}
        ;

classe: "class"^ (IDENTIFIER | IDENTIFIER "<" IDENTIFIER ("<" IDENTIFIER!)*) (statement)* body_class "end"
     ;

// il corpo della classe
body_class : (definition)+
           ;

definition: (statement)* "def"^ IDENTIFIER (IDENTIFIER)* ( "("! (IDENTIFIER)+ (","! IDENTIFIER)* ")"! )* statement (statement)* "end"
          ;

// istruzioni che si possono trovare nel corpo del programma
statement : ("if"^ | "while"^) condition (statement)+ "end"
	  | "loop" "do"^ (statement)+ "end"
	  | "yield"^ "("! (IDENTIFIER | instruction) ")"!
	  | "return"^ ret   
          | IDENTIFIER "="^ (NUMBER | IDENTIFIER | STRING)
	  | IDENTIFIER "="^ instruction
	  | IDENTIFIER "="^ "("! (IDENTIFIER | NUMBER | STRING) ")"!
	  | IDENTIFIER "="^ "("! instruction ")"!
          | IDENTIFIER "="^ IDENTIFIER "("! (IDENTIFIER)+ (","! IDENTIFIER)* ")"!
          | IDENTIFIER ( "("! (IDENTIFIER | NUMBER)+ (","! (IDENTIFIER | NUMBER))* ")"! )* "do"^ "|"! IDENTIFIER "|"! (statement)* "end"
          | IDENTIFIER
          ;
	  
// condizioni o operazioni che si possono scrivere nei costrutti
condition : "("! condition ")"! ((operator | booleano) (IDENTIFIER | NUMBER))?
          | IDENTIFIER booleano IDENTIFIER
          | IDENTIFIER booleano NUMBER
          | NUMBER booleano IDENTIFIER
          | NUMBER booleano NUMBER
	  | instruction
	  | IDENTIFIER booleano instruction
          ;

// istruzioni matematiche
instruction : NUMBER operator NUMBER
	    | IDENTIFIER operator NUMBER
	    | NUMBER operator IDENTIFIER
            | IDENTIFIER operator IDENTIFIER
            ;

// operatori che si possono trovare nelle condizioni
booleano : "<"^
         | "<="^
         | ">="^
	 | ">"^
	 | "=="^
	 | "%"^
	 | "&"^
	 | "|"^;
	// | "("!
	// | ")"!
        // ;

// ciò che può essere scritto con il "return"
ret : IDENTIFIER
    | NUMBER
    | instruction
    | "true"
    | "false"
    | "("! IDENTIFIER ")"!
    | "("! NUMBER ")"!
    | "("! "true" ")"!
    | "("! "false" ")"!
    ;
    
// operatori matematici
operator : "/"^
         | "*"^
	 | "+"^
	 | "-"^
	 | "%"^
         ;


/**
 * LEXER
 **/
class RubyLexer extends Lexer;

options {
  k = 6; // sei caratteri di lookahead
}

// gestione degli spazi tra le varie parole
WS	: ' '{ _ttype = Token.SKIP; }
	;

LPAREN  : '('
	;

RPAREN  : ')'
	;

LT      : '<'
        ;
LE      : "<="
        ;
GE      : ">="
        ;
GT      : '>'
        ;
EGUAL   : "=="
        ;
DIV     : '/'
        ;
MUL     : '*'
        ;
ASSIGN  : '='
        ;
PLUS    : '+'
        ;
OR      : '|' // questo simbolo non ha solo la funzionalità dell'OR!
        ;  
AND     : '&'
        ;
SUB     : '-'
        ;
MOD     : '%'
        ;
NUMBER  : ('0'..'9')+
        ;
	 
// Identificatori
IDENTIFIER : ("@")* ('a'..'z'|'A'..'Z'|'.')+ (NUMBER)*;
	   
// Stringhe
STRING : '"' (('a'..'z'|'A'..'Z')+)* '"'
       | '\'' (('a'..'z'|'A'..'Z')+)* '\'';
	
// regola per il ritorno a capo
NEWLINE : ( "\r\n" // DOS
        | '\r' // MAC
        | '\n' // Unix
        );

/**
 * PARSE TREE    
 **/
class RubyParseTree extends TreeParser;

program: #(PROGRAM (classe | statement)*)
       ;

classe: #("class" (IDENTIFIER)* "<" (statement)* body_class "end")
       ;

body_class: #("def" definition)
          ;

definition: #("def" (IDENTIFIER)* "(" ")" "," (statement)* "end")
          ;

statement: #("if" condition (statement)+ "end")
         | #("while" condition (statement)+ "end")
         | #("yield" "(" (IDENTIFIER | instruction) ")")
        // | #("return" ret)
         | #("=" IDENTIFIER (NUMBER | IDENTIFIER | STRING))
         | #("=" IDENTIFIER instruction)
         | #("=" IDENTIFIER "(" (IDENTIFIER | NUMBER | STRING) ")")
         | #("=" IDENTIFIER "(" instruction ")")
         | #("=" IDENTIFIER IDENTIFIER "(" (IDENTIFIER)+ ("," IDENTIFIER)* ")")
         | #("do" IDENTIFIER ( "(" (IDENTIFIER | NUMBER)+ ("," (IDENTIFIER | NUMBER))* ")" )*  "|" IDENTIFIER "|" (statement)* "end")
         ;

condition: #("/" "(" condition ")" (IDENTIFIER | NUMBER)?)
         | #("*" "(" condition ")" (IDENTIFIER | NUMBER)?)
         | #("+" "(" condition ")" (IDENTIFIER | NUMBER)?)
         | #("-" "(" condition ")" (IDENTIFIER | NUMBER)?)
         | #("%" "(" condition ")" (IDENTIFIER | NUMBER)?)
         | #("<" "(" condition ")" (IDENTIFIER | NUMBER)?)
         | #("<" IDENTIFIER IDENTIFIER)
         | #("<" IDENTIFIER instruction)
         | #("<=" "(" condition ")" (IDENTIFIER | NUMBER)?)
         | #("<=" IDENTIFIER IDENTIFIER)
         | #("<=" IDENTIFIER instruction)
         | #(">=" "(" condition ")" (IDENTIFIER | NUMBER)?)
         | #(">=" IDENTIFIER IDENTIFIER)
         | #(">=" IDENTIFIER instruction)
         | #(">" "(" condition ")" (IDENTIFIER | NUMBER)?)
         | #(">" IDENTIFIER IDENTIFIER)
         | #(">" IDENTIFIER instruction)
         | #("==" "(" condition ")" (IDENTIFIER | NUMBER)?)
         | #("==" IDENTIFIER IDENTIFIER)
         | #("==" IDENTIFIER instruction)
         | #("%" "(" condition ")" (IDENTIFIER | NUMBER)?)
         | #("%" IDENTIFIER IDENTIFIER)
         | #("%" IDENTIFIER instruction)
         | #("&" "(" condition ")" (IDENTIFIER | NUMBER)?)
         | #("&" IDENTIFIER IDENTIFIER)
         | #("&" IDENTIFIER instruction)
         | #("|" "(" condition ")" (IDENTIFIER | NUMBER)?)
         | #("|" IDENTIFIER IDENTIFIER)
         | #("|" IDENTIFIER instruction)
         ; 

instruction: #("/" NUMBER NUMBER)
           | #("/" IDENTIFIER NUMBER)
           | #("/" NUMBER IDENTIFIER)
           | #("/" IDENTIFIER IDENTIFIER)
           | #("*" NUMBER NUMBER)
           | #("*" IDENTIFIER NUMBER)
           | #("*" NUMBER IDENTIFIER)
           | #("*" IDENTIFIER IDENTIFIER)
           | #("+" NUMBER NUMBER)
           | #("+" IDENTIFIER NUMBER)
           | #("+" NUMBER IDENTIFIER)
           | #("+" IDENTIFIER IDENTIFIER)
           | #("-" NUMBER NUMBER)
           | #("-" IDENTIFIER NUMBER)
           | #("-" NUMBER IDENTIFIER)
           | #("-" IDENTIFIER IDENTIFIER)
           | #("%" NUMBER NUMBER)
           | #("%" IDENTIFIER NUMBER)
           | #("%" NUMBER IDENTIFIER)
           | #("%" IDENTIFIER IDENTIFIER)
           ;