parser.y

%{
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    #include <stdarg.h>
    #include <ctype.h>

    int create_Var          = 1;
    int If_Lable_Counter    = 1;
    int For_Label_Counter   = 1;
    int While_Lable_Counter = 1;

    char Myvar[50];
    char Mynum[50];
    char sign[50];


    extern int yylex();
    extern FILE *yyin;
    extern FILE *yyout;

    /* prints grammar violation message */
    void yyerror(char *msg);

%}

%start Program

%union{
    int labelCounter;
    char relo[500];
    char id[500];
    char num[500];
    char arithP[500];
    char arithD[500];
    char nonTerminal[500];
}


%token <num> NUM
%token <id> ID
%token <labelCounter> IF ELSE WHILE FOR IN RANGE
%token <relo>  RELOP
%token <arithP> ARITHP
%token <arithD> ARITHD

%type <nonTerminal>  block stmts stmt  optexpr IDs expr rel add term power factor 

/* Precedence Operator */

%right '='
%right "**"
%left  RELOP
%left  '-' '+'
%left  '*' '/'
%left  UMINUS 

%%

Program : block                       { ; }
        ;

block   : '{' stmts '}'               { printf("\n"); }
        | stmts                       { printf("\n"); }
        ;

stmts   : stmts  stmt                 { ; }
        | %empty                      
        ;

stmt    : optexpr ';'	              { printf(";\n"); }
        | expr    ';'	              { printf(""); }


        |IF                           { printf("IF_BEGIN_%d:\n", $1=If_Lable_Counter++); printf("\n"); }
        '('                           { printf("IF_CONDITION_%d:\n", $1); printf("\n"); }
        expr ')'                      { printf("ifTrue (%s) goto ELSE_CODE_%d;\n", $5, $1); printf("goto IF_CODE_%d;\n", $1); printf("\n"); }
                                      { printf("IF_CODE_%d:\n", $1); }
        stmt                          { printf("goto ELSE_END_%d;\n", $1); }

        |ELSE                         { printf("ELSE_CODE_%d:\n", $1); } 
        stmt                          { printf("ELSE_END_%d:\n", $1); printf("\n"); } 

        |FOR                          { printf("FOR_BEGIN_%d:\n", $1=For_Label_Counter++); }
          optexpr                     { ; }
          IN                           
          RANGE
          '('                               
          optexpr                         
          ')'                         { printf("FOR_CONDITION_%d:\n", $1); sprintf($3, "t%d", create_Var++); printf("%s = %s < %s;\n", $3, Myvar, Mynum);  }
                                      { printf("ifFalse (%s) goto FOR_END_%d;\n", $3, $1);  printf("goto FOR_CODE_%d:\n", $1); 
                                        printf("FOR_STEP_%d:\n", $1);   sprintf($3, "t%d", create_Var++);   printf("%s = %s + 1;\n", $3, Myvar);
                                        printf("%s = %s;\n", Myvar,$3); printf("goto FOR_CONDITION_%d:\n", $1);  printf("FOR_CODE_%d:\n", $1); }                                                            
          stmt                         
                                      
                                      { printf("goto FOR_STEP_%d;\n", $1); printf("FOR_END_%d:\n", $1); }
        

        |WHILE                        { printf("WHILE_BEGIN_%d:\n", $1=While_Lable_Counter++); printf("\n"); } 
        '('                           { printf("WHILE_CONDITION_%d:\n", $1); printf("\n"); }
        expr ')'                      { printf("ifFalse (%s) goto WHILE_END_%d;\n", $5, $1); printf("goto WHILE_CODE_%d;\n", $1); printf("}\n"); printf("WHILE_CODE_%d:\n", $1); } 
        stmt                          { printf("goto WHILE_CONDITION_%d;\n", $1); printf("\n"); printf("WHILE_END_%d:\n", $1); }

        |block                        
        ;

optexpr:    
        expr                         { strcpy($$, $1); }
        | ID                         { strcpy($$, $1); printf("%s = 0;\n", $1); strcpy(Myvar, $1);}
        | NUM                        { strcpy($$, $1); strcpy(Mynum, $1);}
        |%empty                      { ; }
        ;

IDs     : IDs ',' ID	             { sprintf($$, "%s, %s", $1, $3); }
	| IDs ',' ID '=' expr	         { sprintf($$, "%s, %s = %s", $1, $3, $5); }
	| ID			                 { sprintf($$, "%s",$1);}
	| ID '=' expr	                 { sprintf($$, "%s = %s", $1, $3); }
	;


expr    : ID '=' expr               { strcpy($$, $3); printf("%s = %s;\n", $1, $3); }
        | rel                       { strcpy($$, $1); }
        ;

rel     : rel RELOP add             { sprintf($$, "t%d", create_Var++); printf("%s = %s %s %s;\n", $$, $1, $2, $3); }
        | add                       { strcpy($$, $1);}
        ;

add     : add '+' term              { sprintf($$, "t%d", create_Var++); printf("%s = %s + %s;\n", $$, $1, $3); }
        | add '-' term              { sprintf($$, "t%d", create_Var++); printf("%s = %s - %s;\n", $$, $1, $3); }
        | term                      { strcpy($$, $1);}
        ;

term    : term '*' power           { sprintf($$, "t%d", create_Var++); printf("%s = %s * %s;\n", $$, $1, $3); }
        | term '/' power           { sprintf($$, "t%d", create_Var++); printf("%s = %s / %s;\n", $$, $1, $3); }
        | term ARITHD power        { sprintf($$, "t%d", create_Var++); printf("%s = %s // %s;\n", $$, $1, $3); }
        | term '%' power           { sprintf($$, "t%d", create_Var++); printf("%s = %s % %s;\n", $$, $1, $3); }
        | power                    { strcpy($$, $1); }
        ;

power   : factor ARITHP power      { sprintf($$, "t%d", create_Var++); printf("%s = %s ** %s;\n", $$, $1, $3); }
        | factor                   { strcpy($$, $1); }
        ;

factor  : '(' expr ')'             { strcpy($$, $2); }
        | '-' factor               { strcpy(sign,"-"); strcat(sign,$2); strcpy($$, sign); }
        | NUM                      { strcpy($$, $1); }
        | ID                       { strcpy($$, $1); }
        ;

%%

void yyerror(char *msg) {
    fprintf(stderr,"%s\n",msg);
    exit(1);
}


int yywrap() {
    return 1;
}

int main() {
   yyparse();
}