// This code has a bug that is explained in ../gc.html
#include "h.h"
#include <stdlib.h>
void crsh(char* d, cp c){exit(printf("%s: compiler bug at %d!", d, c-code));}

val eval(cp x, env * e){ // Use the stack at first
  uchar op = *x;
  if(op < 253) {while(op--) if (e) e = e->out; else crsh("bad sym\n", x); return e->v;}
  if(op == 254) {cp argE = 3+x+*(us *)(x+1); // Where exp for argument is at.
     val f = eval(x+3, e); // function to apply
     val a = eval(argE, e); // argument to apply it to
     if(f.tag == 2) {
         if(a.tag) Bye("Numeric operator applied to function");
         return f.u.p(a.u.i);}
     {env * e2 = alloca(sizeof(env)); *e2 = (env){a, f.u.f.e};
      if (f.tag) return eval(f.u.f.c, e2);
      Bye("number as function");}}
  if(op == 255) return (val){1, {.f = {e, x+1}}};
  {nis y = 0; ++x; do y = y<<7 | (*x & 0x7f); while(*(x++) < 0x80) ;
     return (val){0, { .i = y }};}}

/* 172% ./replr2
(K 4 6)
code = fe 06 00 fe 01 00 00 fd 84 fd 86
val = 32658931318788
^C
172% ./repl2 
(K 4 6)
code = fe 06 00 fe 01 00 00 fd 84 fd 86
val = 4
 */