%{

#include "mbasic.h"
#include "mbasic.c"

%}

%union 
{
	double       number;
	char         *string;
	int          boolean;
};

%token <string>  UNREC

%token <string>  STRLIT 
%token <boolean> SVAR
%type  <string>  sexpr

%token <number>  NUMLIT 
%token <boolean> NVAR
%type  <number>  nexpr

%token <boolean> BOOLIT
%token <boolean> BVAR
%type  <boolean> bexpr 

%token EOL
%token CLS
%token INPUT
%token PRINT
%token DIM
%token AS
%token NUMBER
%token STRING
%token BOOLEAN
%token IF THEN ELSE
%token AND OR NOT 
%token EQ NE GT GE LT LE
%token '=' 

%left  '-' '+'
%left  '*' '/'
%right '^'

%%

input:	  /* empty */
	| input line
;

line:	  EOL	
	| stmt EOL
	| error EOL { yyerrok; }
;

stmt:	  CLS                                 { system("clear"); }
	| PRINT nexpr                         { printf("%f\n",$2); } 
	| PRINT sexpr                         { printf("%s\n",$2); }
	| PRINT                               { printf("\n"); };

	| INPUT UNREC                         { yyerror("Variable not defined"); }

	| INPUT NVAR                          { InputNumber(stdin,$2,0); }
	| INPUT STRLIT ';' NVAR               { printf("%s",$2); InputNumber(stdin,$4,0); }
	| INPUT NVAR '(' nexpr ')'            { InputNumber(stdin,$2,$4); }
	| INPUT STRLIT ';' NVAR '(' nexpr ')' { printf("%s",$2); InputNumber(stdin,$4,$6); }

	| INPUT SVAR                          { InputString(stdin,$2,0); }
	| INPUT STRLIT ';' SVAR               { printf("%s",$2); InputString(stdin,$4,0); }
	| INPUT SVAR '(' nexpr ')'            { InputString(stdin,$2,$4); }
	| INPUT STRLIT ';' SVAR '(' nexpr ')' { printf("%s",$2); InputString(stdin,$4,$6); }

	| DIM UNREC AS NUMBER                 { Dim($2,0,TP_NUMBER); } 
	| DIM UNREC '(' nexpr ')' AS NUMBER   { Dim($2,$4,TP_NUMBER); } 

	| UNREC '=' nexpr                     { yyerror("Variable not defined"); }
	| NVAR '=' nexpr                      { PutNumber($1,0,$3); }
	| NVAR '(' nexpr ')' '=' nexpr        { PutNumber($1,$3,$6); } 

	| DIM UNREC AS STRING                 { Dim($2,0,TP_STRING); } 
	| DIM UNREC '(' nexpr ')' AS STRING   { Dim($2,$4,TP_STRING); } 

	| UNREC '=' sexpr                     { yyerror("Variable not defined"); }
	| SVAR '=' sexpr                      { PutString($1,0,$3); }
	| SVAR '(' nexpr ')' '=' sexpr        { PutString($1,$3,$6); } 

	| DIM UNREC AS BOOLEAN                { Dim($2,0,TP_BOOLEAN); } 
	| DIM UNREC '(' nexpr ')' AS BOOLEAN  { Dim($2,$4,TP_BOOLEAN); } 

	| BVAR '=' UNREC                      { yyerror("Variable not defined"); }
	| BVAR '=' bexpr                      { PutBoolean($1,0,$3); }
	| BVAR '(' nexpr ')' '=' bexpr        { PutBoolean($1,$3,$6); } 

	| IF bexpr                            { printf("Answer: %i\n",$2); }
;

nexpr:	  NUMLIT                        { $$ = $1; }
	| NVAR                          { $$ = GetNumber($1,0); }
	| NVAR '(' nexpr ')'            { $$ = GetNumber($1,$3); }
	| '-' nexpr                     { $$ = 0-$2; }
	| nexpr '+' nexpr               { $$ = $1 + $3; }
	| nexpr '-' nexpr               { $$ = $1 - $3; }
	| nexpr '*' nexpr               { $$ = $1 * $3; }
	| nexpr '/' nexpr               { $$ = $1 / $3; }
	| '(' nexpr ')'                 { $$ = $2; }
;

sexpr:	  STRLIT                        { $$ = $1; }
	| SVAR                          { $$ = GetString($1,0); }
	| SVAR '(' nexpr ')'            { $$ = GetString($1,$3); }
	| sexpr '+' sexpr               { $$ = ConcatString($1,$3); }
	| sexpr '+' nexpr               { $$ = ConcatString($1,Str($3)); }
;

bexpr:	  BOOLIT                        { $$ = $1; }
	| nexpr EQ nexpr                { if($1 == $3) { $$ = 1; } else { $$ = 0; } }
	| nexpr NE nexpr                { if($1 != $3) { $$ = 1; } else { $$ = 0; } }
	| nexpr GT nexpr                { if($1 >  $3) { $$ = 1; } else { $$ = 0; } }
	| nexpr GE nexpr                { if($1 >= $3) { $$ = 1; } else { $$ = 0; } }
	| nexpr LT nexpr                { if($1 <  $3) { $$ = 1; } else { $$ = 0; } }
	| nexpr LE nexpr                { if($1 <= $3) { $$ = 1; } else { $$ = 0; } }
	| bexpr AND bexpr               { if($1 && $3) { $$ = 1; } else { $$ = 0; } }
;

%%

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