%{
#include <iostream>
#include <stack>
#include <string>
#include <stdio.h>
#include <stdlib.h>

  using namespace std;

  extern int yylex();
  extern void yyerror(const char*);
  extern int yyparse();

  string prog_string;

typedef union {
  int i_val;     /*don't need this for proj 1.*/
  std::string* s_val;
} YYSTYPE;

 extern YYSTYPE yyval;

%}

%union {
  int i_val;
  std::string* s_val;
}

%token UMINUS
%token C_STRING
%token C_INTEGER
%token STRING
%token VOID
%token INT
%token CHAR
%token RETURN
%token IF
%token ELSE
%token FOR
%token WHILE
%token EXTERN
%token STRUCT

%token OP_PAR
%token CL_PAR
%token OP_SQU
%token CL_SQU
%token OP_BCS
%token CL_BCS
%token OP_PL
%token OP_PP
%token OP_MI
%token OP_MM
%token OP_MU
%token OP_DIV
%token OP_XOR
%token OP_EQ
%token OP_EQ_EQ
%token OP_NOT
%token OP_NE
%token OP_SEM
%token OP_CM
%token OP_LT
%token OP_GT
%token OP_LE
%token OP_GE
%token OP_QU
%token OP_SQ
%token ELLIPSIS
%token AMP_AMP
%token OR_OR

%left OR_OR
%left AMP_AMP
%left OP_NE OP_EQ_EQ
%left OP_LT OP_LE OP_GT OP_GE
%left OP_PL OP_MI
%left OP_MU OP_DIV
%nonassoc UMINUS OP_NOT

%type <s_val> element
%type <s_val> function
%type <s_val> fun_prot
%type <s_val> statements
%type <s_val> statement
%type <s_val> assign
%type <s_val> decls
%type <s_val> arith_expr
%type <s_val> variable

%%

program:                       { }
       | element program       { prog_string = (*$1) + prog_string; }
       ;

element: function              { $$ = $1; }
       ;

function : fun_prot OP_BCS decls statements CL_BCS       { $$ = new string("function(" + *$1 + "OP_BCS \n" + *$3 + *$4 + "CL_BCS \n)\n"); }
	;

fun_prot:                      { }
	;

statements:				{ $$ = new string(""); }
	| statement statements		{ $$ = new string(*$1 + *$2); }
	;

statement: assign OP_SEM       		{ $$ = new string("statement(" + *$1 + ")\n"); }
	| RETURN arith_expr OP_SEM     	{ $$ = new string("statement(RETURN " + *$2 + ")\n"); }
	;

assign: variable OP_EQ arith_expr 	{ }
	;

decls: 	                        { }
;

arith_expr: variable			{ $$ = new string("a_expr(" + *$1 + ") "); }
	| OP_MI arith_expr %prec UMINUS	{ $$ = new string("a_expr(OP_MI " + *$2 + ") "); }
	| arith_expr OP_MU arith_expr	{ $$ = new string("a_expr(" + *$1 + "OP_MU " + *$3 + ") "); }
	| arith_expr OP_MI arith_expr	{ $$ = new string("a_expr(" + *$1 + "OP_MI " + *$3 + ") "); }
	;

variable: C_STRING			        { $$ = new string("var "); }
	;

%%

int main()
{
  prog_string = "";
  yyparse();
  cout<<prog_string;

  return 1;
}