%{
#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include "lex.yy.c"
extern int yylval;
 int symcount=0;
 int strcount=0;
int mytreecount=0;
 int temp;
 char mys[80];
struct {
   char op;
   int lefttable, left,righttable,right;

 } mytree[5000];

typedef int YYSTYPE;
 %}
%token GE
%token LE
%token READ
%token ID
%token EQEQ
%token ASSIGN
%token NUM
%token PRINT
%token IF
%token DO
%token NEWLINE
%token THEN
%token STR
%token ELSE
%token WHILE
%token ENDIF
%token ENDWHILE
%left '+' '-' '<' '>' GE LE EQEQ 
%left '*' '/'
%left UMINUS

%start stmtlist

%%
stmtlist: stmtlist  stmt  { $$ = myinsert(';',1,$1,1,$2);
  }
| stmt  { $$= $1;}
;
stmt: ID ASSIGN expr ';' { $$ =myinsert('=',0,$1,1,$3); }
| PRINT expr ';' { $$ = myinsert('P',1,$2,0,0); }
| PRINT STR ';' { $$ = myinsert('p',2,$2,0,0);}
| PRINT NEWLINE ';' { $$ = myinsert('q',2,$2,0,0);}
| IF  expr   THEN stmtlist  ELSE  stmtlist ENDIF { $$=myinsert('i',1,$2,0,0);temp=myinsert('i',1,$4,1,$6); } 
| IF  expr   THEN stmtlist  ENDIF { $$=myinsert('I',1,$2,1,$4); } 
| WHILE  expr  DO  stmtlist ENDWHILE { $$=myinsert('d',1,$2,1,$4);}
   ;
expr : expr '+' expr  { $$ =myinsert('+',1,$1,1,$3);}
    | expr '-' expr { $$ =myinsert('-',1,$1,1,$3); }
     | expr '/' expr  { $$ =myinsert('/',1,$1,1,$3);}
| expr '*' expr { $$ = myinsert('*',1,$1,1,$3); }
| '(' expr ')' { $$ =  $2;}
       | ID { $$ = myinsert('L',0,yylval,0,0);}
       | NUM {$$ = myinsert('L',0,yylval,0,0);}
       | expr '>' expr  { $$ =myinsert('>',1,$1,1,$3);}
       | expr '<' expr  { $$ =myinsert('<',1,$1,1,$3);}
       | expr EQEQ expr  { $$ = myinsert('e',1,$1,1,$3);}
       | expr GE expr  { $$ = myinsert('g',1,$1,1,$3);}
       ;

%%
void yyerror(char *msg);
YYSTYPE myinsert(char op, int lefttable, YYSTYPE left, int righttable,YYSTYPE right);
void list_mytree(void);
void list_table(void);
int evaluate_tree(int);

int main()
{
    do  
    {
      yyparse();
     list_mytree();
     evaluate_tree(mytreecount-1);
     list_table();


    }
      while(!feof(stdin));
    return 1; 
}

void yyerror(char *msg)
{
 printf("%s\n",msg);
}

YYSTYPE myinsert(char op, int lefttable,YYSTYPE left, int righttable,YYSTYPE right)
{

mytree[mytreecount].op =op;
 mytree[mytreecount].lefttable=lefttable;
mytree[mytreecount].left =left;
 mytree[mytreecount].righttable=righttable;
mytree[mytreecount].right =right;
mytreecount++;
return (mytreecount-1);
}

int evaluate_tree(int i) {     
  int leftvalue,rightvalue;  

  /*  printf("Node executing %d\n",i);*/
  switch (mytree[i].op) {

    case '+':  leftvalue = evaluate_tree(mytree[i].left);
             rightvalue = evaluate_tree(mytree[i].right);
             return leftvalue+rightvalue;
    case '>':  leftvalue = evaluate_tree(mytree[i].left);
             rightvalue = evaluate_tree(mytree[i].right);
             return leftvalue>rightvalue;
    case '<':  leftvalue = evaluate_tree(mytree[i].left);
             rightvalue = evaluate_tree(mytree[i].right);
               return (leftvalue < rightvalue);
    case 'e':  leftvalue = evaluate_tree(mytree[i].left);
             rightvalue = evaluate_tree(mytree[i].right);
             return leftvalue==rightvalue;
    case 'g':  leftvalue = evaluate_tree(mytree[i].left);
             rightvalue = evaluate_tree(mytree[i].right);
             return leftvalue>=rightvalue;
    case '*':  leftvalue = evaluate_tree(mytree[i].left);
             rightvalue = evaluate_tree(mytree[i].right);
             return leftvalue*rightvalue;
    case '-':  leftvalue = evaluate_tree(mytree[i].left);
             rightvalue = evaluate_tree(mytree[i].right);
             return leftvalue-rightvalue;
    case '/':  leftvalue = evaluate_tree(mytree[i].left);
             rightvalue = evaluate_tree(mytree[i].right);
             return leftvalue/rightvalue;
  case '=': rightvalue = evaluate_tree(mytree[i].right);
    sym_tbl[mytree[i].left].value=rightvalue;
    return 1;
 
  case 'L': return sym_tbl[mytree[i].left].value;
  case ';':   leftvalue = evaluate_tree(mytree[i].left);
             rightvalue = evaluate_tree(mytree[i].right);
             return 1;
  case 'P' : leftvalue=evaluate_tree(mytree[i].left);
             printf("%d", leftvalue); return 1;
  case 'q' :  printf("\n"); return 1;
  case 'p':     printf("%s",str_tbl[mytree[i].left]);

    return 1;
  default: printf("How did I get here?\n"); exit(0);

  }
} 

void list_mytree (void)
{
 int i;
 /* printf("Derivation code\n"); */
 /* printf("mytreecount %d\n", mytreecount); */
 printf("mytree\t           \n");


for(i=0;i<mytreecount;i++)
  { 
    printf("mytree (%d )\t(%c %2d %2d %2d %2d )\n", i,mytree[i].op,mytree[i].lefttable,mytree[i].left,mytree[i].righttable,mytree[i].right);
							   
  }
}

void list_table(void)
{ int i;

printf("Symbol Table\n");

for (i=1; i<=symcount;i++)
printf("%2d: %s %d\n",i,sym_tbl[i].mysymbol,sym_tbl[i].value);
printf("\n");
for (i=1; i<=strcount;i++)
printf("%s \n",str_tbl[i]);
printf("\n");

}