dparser/4calc.g at main · jplevyak/dparser · GitHub

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{
#include <stdio.h>
#include <stdlib.h>

typedef struct My_ParseNode {
  int value;
} My_ParseNode;
#define D_ParseNode_User My_ParseNode
}

translation_unit :
      statement*
   ;

statement :
      expr ';' { printf("%d\n", $0.value); }
   ;

expr :
      integer                    { $$.value = atoi($n0.start_loc.s); }
   |  expr '+' expr  $right 10   { $$.value = $0.value + $2.value; }
   |  expr '-' expr  $right 10   { $$.value = $0.value - $2.value; }
   |  expr '*' expr  $right 20   { $$.value = $0.value * $2.value; }
   |  expr '/' expr  $right 20   { $$.value = $0.value / $2.value; }
   |   '(' expr ')'              { $$.value = $1.value; }
   ;

integer :
      "-?[0-9]+"
   ;