%{   int variavel[27], ultimo;

#include <stdio.h>
#include "xmc.h"
  SEXP _JJ;

#define reg(x) variavel[x-'a']
#define infix(x) $$=f2(x,$1,$3)
#define infixs $$=conssexp($2,l2sexp($1,$3))

%}

%union {SEXP val;}

%token JINT JSYM JSTR OPREL

%type <val>  JINT OPREL JSYM JSTR E 

%right '='
%left '+' '-'
%left '*' '/'
%left opuna


%%
Z      : {_JJ=(SEXP) NULL;} E '$'  {_JJ=$2; return(1);}
       ;

E      : E '+' E     {infix("add");}
       | E '-' E     {infix("sub");}
       | E '/' E     {infix("div");}
       | E '*' E     {infix("mul");}
       | '(' E ')'   {$$=$2;}
       | JINT        {$$=$1;}
       | '+' E  %prec opuna     {$$=$2;}       
       | '-' E  %prec opuna     {$$=f2("sub",intsex(0),$2);}       
       | '.'         {$$=symsexp("ultimo");}
       | JSYM        {$$=$1;}
       | JSYM '=' E  {infix("def");}
       | E OPREL E   {infixs;}
       ;

%%

SEXP jjparse(d)
SEXP d;
{ yyparse(); return _JJ;}

void userinit() {xlsubr("parse",jjparse);}

#include "lex.yy.c"