grammar Calculette;

@members {

    private TablesSymboles tablesSymboles = new TablesSymboles();

    private int _label = 0;
    /** générateur de nom d'étiquettes */
    private int nextLabel() { return _label++; }

        }


// lexer
VAR : 'var' ;

start
    : a=calcul EOF {System.out.println($a.code);};

expr returns [ String code ]
@init { $code = new String(); }
   : '(' k=expr ')' {$code = $k.code;}
   | '-' j=expr {$code = "PUSHI 0\n"+ $j.code + "SUB\n";}
   | a=expr '*' b=expr {$code = $a.code + $b.code + "MUL\n";}
   | c=expr '/' d=expr {$code = $c.code + $d.code + "DIV\n";}
   | g=expr '-' h=expr {$code = $g.code + $h.code + "SUB\n";}
   | e=expr '+' f=expr {$code = $e.code + $f.code + "ADD\n";}
   | id=IDENTIFIANT { $code = "PUSHG " + tablesSymboles.adresseVar($id.text) + "\n";}
   | i=ENTIER {$code = "PUSHI " + $i.text + "\n";}
   ;

// lexer
IDENTIFIANT  : (('a'..'z' | 'A'..'Z' | '_')('a'..'z' | 'A'..'Z' | '_' | '0'..'9')*);



finInstruction
    : (';' | NEWLINE)
    ;

assignation returns [ String code ]
    : a=IDENTIFIANT '=' b=expr
        {
            $code = $b.code + "STOREG " + tablesSymboles.adresseVar($a.text) + "\n";
        }
    ;

condition returns [String code]
    : orGauche=condition 'ou' orDroite=condition { $code = $orGauche.code + $orDroite.code + "ADD\n"; }
    | andGauche=condition 'et' andDroite=condition { $code = $andGauche.code + $andDroite.code + "MUL\n"; }
    | 'non' notDroite=condition { $code = "PUSHI 0 \n" + $notDroite.code + "SUPEQ\n"; }
    | 'true'  { $code = "PUSHI 1\n"; }
    | 'false' { $code = "PUSHI 0\n"; }
    | infeqGauche=expr '<=' infeqDroite=expr { $code = $infeqGauche.code + $infeqDroite.code + "INFEQ\n"; }
    | supeqGauche=expr '>=' supeqDroite=expr { $code = $supeqGauche.code + $supeqDroite.code + "SUPEQ\n"; }
    | infGauche=expr '<' infDroite=expr { $code = $infGauche.code + $infDroite.code + "INF\n"; }
    | supGauche=expr '>' supDroite=expr { $code = $supGauche.code + $supDroite.code + "SUP\n"; }
    | equalGauche=expr '==' equalDroite=expr { $code = $equalGauche.code + $equalDroite.code + "EQUAL\n"; }
    ;

bouclewhile returns [String code]
    : 'while' '(' con=condition ')' ins=instruction
        {
            int debLabel = nextLabel();
            int finLabel = nextLabel();
            $code = "LABEL " + debLabel + "\n";
            $code += $con.code;
            $code += "JUMPF " + finLabel + "\n";
            $code += $ins.code;
            $code += "JUMP " + debLabel + "\n";
            $code += "LABEL " + finLabel + "\n";

        }
    ;

repeatuntil returns [ String code ]
    : 'repeat' ins=blocinstructions 'until' con=condition
        {
            int debLabel = nextLabel();
            int finLabel = nextLabel();
            $code = "LABEL " + debLabel + "\n";
            $code += $ins.code;
            $code += "PUSHI 0\n";
            $code += $con.code;
            $code += "EQUAL \n";
            $code += "JUMPF " + finLabel + "\n";
            $code += "JUMP " + debLabel + "\n";
            $code += "LABEL " + finLabel + "\n";
        }
    ;

ifelse returns [ String code ]
    @init{ boolean sinon = false;}
    : 'if' '(' con=condition ')' gauche=instruction ('else' droite=instruction {sinon = true;})?
        {
            int debLabel = nextLabel();
            int finLabel = nextLabel();
            $code += $con.code;
            $code += "JUMPF " + debLabel + "\n";
            if(sinon){
                $code += $droite.code;
                $code += "JUMP " + finLabel + "\n";
            }
            $code += "LABEL " + debLabel + "\n";
            $code += $gauche.code;
            $code += "LABEL " + finLabel + "\n";
        }
        ;


blocinstructions returns [ String code ]
@init { $code = new String(); $code = ""; }
    : {$code = "";} '{' (ins=instruction {$code += $ins.code;})* '}'
    ;

instruction returns [ String code ]
    : z=expr finInstruction
        {
            $code = $z.code;
        }
    | w=assignation finInstruction
        {
            $code = $w.code;
        }
    | a=bouclewhile finInstruction
        {
            $code = $a.code;
        }
    | rep=repeatuntil finInstruction
        {
            $code = $rep.code;
        }
    | ife=ifelse finInstruction
        {
            $code = $ife.code;
        }
    | finInstruction
        {
            $code = "";
        }
    ;

decl returns [ String code ]
    : VAR a=IDENTIFIANT finInstruction
        {
          tablesSymboles.putAdresse($a.text);
          $code = "PUSHI 0\n";
        }
    ;


calcul returns [ String code ]
@init{ $code = new String(); }   // On initialise $code, pour ensuite l'utiliser comme accumulateur
    :   (decl { $code += $decl.code; })*

        NEWLINE*

        (instruction { $code += $instruction.code; })*

        { $code += "HALT\n"; }
    ;


NEWLINE : '\r'? '\n';

WS :   (' '|'\t')+ -> skip  ;

ENTIER : ('0'..'9')+  ;

UNMATCH : . -> skip ;