#include <string.h>
#include <stdbool.h>
#include "fh_runtime.h"
#include "fh_config.h"
#include "fh_error.h"
#include "fh_print.h"
#include "fh_builtins.h"
#include "fh_stack.h"
#include "fh_mem.h"

#define TOBOOL(a) (a == 0 ? 0 : 0xFFFFFFFF)


/**
 * Encode a code point using UTF-8
 *
 * Copied from ESPTERM source
 *
 * @param out - output buffer (min 4 characters), will be 0-terminated if shorten than 4
 * @param utf - code point 0-0x10FFFF
 * @return number of bytes on success, 0 on failure (also produces U+FFFD, which uses 3 bytes)
 */
static int utf8_encode(char *out, uint32_t utf)
{
  if (utf <= 0x7F) {
    // Plain ASCII
    out[0] = (char) utf;
    out[1] = 0;
    return 1;
  } else if (utf <= 0x07FF) {
    // 2-byte unicode
    out[0] = (char) (((utf >> 6) & 0x1F) | 0xC0);
    out[1] = (char) (((utf >> 0) & 0x3F) | 0x80);
    out[2] = 0;
    return 2;
  } else if (utf <= 0xFFFF) {
    // 3-byte unicode
    out[0] = (char) (((utf >> 12) & 0x0F) | 0xE0);
    out[1] = (char) (((utf >> 6) & 0x3F) | 0x80);
    out[2] = (char) (((utf >> 0) & 0x3F) | 0x80);
    out[3] = 0;
    return 3;
  } else if (utf <= 0x10FFFF) {
    // 4-byte unicode
    out[0] = (char) (((utf >> 18) & 0x07) | 0xF0);
    out[1] = (char) (((utf >> 12) & 0x3F) | 0x80);
    out[2] = (char) (((utf >> 6) & 0x3F) | 0x80);
    out[3] = (char) (((utf >> 0) & 0x3F) | 0x80);
//		out[4] = 0;
    return 4;
  } else {
    // error - use replacement character
    out[0] = (char) 0xEF;
    out[1] = (char) 0xBF;
    out[2] = (char) 0xBD;
    out[3] = 0;
    return 0;
  }
}


static enum fh_error w_plus(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a = 0, b = 0;
  TRY(ds_pop(fh, &a));
  TRY(ds_pop(fh, &b));
  TRY(ds_push(fh, a + b));
  return FH_OK;
}

static enum fh_error w_minus(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a = 0, b = 0;
  TRY(ds_pop(fh, &a));
  TRY(ds_pop(fh, &b));
  TRY(ds_push(fh, a - b));
  return FH_OK;
}

static enum fh_error w_star(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a = 0, b = 0;
  TRY(ds_pop(fh, &a));
  TRY(ds_pop(fh, &b));
  TRY(ds_push(fh, a * b));
  return FH_OK;
}

static enum fh_error w_zero_less(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a = 0;
  TRY(ds_pop(fh, &a));
  TRY(ds_push(fh, TOBOOL(a < 0)));
  return FH_OK;
}

static enum fh_error w_zero_greater(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a = 0;
  TRY(ds_pop(fh, &a));
  TRY(ds_push(fh, TOBOOL(a > 0)));
  return FH_OK;
}

static enum fh_error w_zero_equals(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a = 0;
  TRY(ds_pop(fh, &a));
  TRY(ds_push(fh, TOBOOL(a == 0)));
  return FH_OK;
}

static enum fh_error w_zero_not_equals(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a = 0;
  TRY(ds_pop(fh, &a));
  TRY(ds_push(fh, TOBOOL(a != 0)));
  return FH_OK;
}


static enum fh_error w_less(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a = 0, b = 0;
  TRY(ds_pop(fh, &b));
  TRY(ds_pop(fh, &a));
  TRY(ds_push(fh, TOBOOL(a < b)));
  return FH_OK;
}

static enum fh_error w_greater(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a = 0, b = 0;
  TRY(ds_pop(fh, &b));
  TRY(ds_pop(fh, &a));
  TRY(ds_push(fh, TOBOOL(a > b)));
  return FH_OK;
}

static enum fh_error w_equals(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a = 0, b = 0;
  TRY(ds_pop(fh, &b));
  TRY(ds_pop(fh, &a));
  TRY(ds_push(fh, TOBOOL(a == b)));
  return FH_OK;
}

static enum fh_error w_not_equals(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a = 0, b = 0;
  TRY(ds_pop(fh, &b));
  TRY(ds_pop(fh, &a));
  TRY(ds_push(fh, TOBOOL(a != b)));
  return FH_OK;
}

static enum fh_error wp_add(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  enum fh_error rv;
  uint32_t a = 0;
  TRY(ds_pop(fh, &a));
  TRY(ds_push(fh, a + w->param));
  return FH_OK;
}

static enum fh_error wp_mul(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  enum fh_error rv;
  uint32_t a = 0;
  TRY(ds_pop(fh, &a));
  TRY(ds_push(fh, a * w->param));
  return FH_OK;
}

static enum fh_error wp_div(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  enum fh_error rv;
  uint32_t a = 0;
  TRY(ds_pop(fh, &a));
  TRY(ds_push(fh, a * w->param));
  return FH_OK;
}

static enum fh_error w_star_slash(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a = 0, b = 0, c = 0;
  TRY(ds_pop(fh, &c));
  TRY(ds_pop(fh, &b));
  TRY(ds_pop(fh, &a));

  if (c == 0) {
    return FH_ERR_DIV_BY_ZERO;
  }

  uint64_t v = ((uint64_t) a * (uint64_t) b) / (uint64_t) c;

  TRY(ds_push(fh, (uint32_t) v));
  return FH_OK;
}

static enum fh_error w_slash(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a = 0, b = 0;
  TRY(ds_pop(fh, &b));
  TRY(ds_pop(fh, &a));

  if (b == 0) {
    return FH_ERR_DIV_BY_ZERO;
  }

  TRY(ds_push(fh, a / b));
  return FH_OK;
}

static enum fh_error w_slash_mod(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a = 0, b = 0;
  TRY(ds_pop(fh, &b));
  TRY(ds_pop(fh, &a));

  if (b == 0) {
    return FH_ERR_DIV_BY_ZERO;
  }

  uint32_t rem = a % b;
  uint32_t div = a / b;

  TRY(ds_push(fh, rem));
  TRY(ds_push(fh, div));
  return FH_OK;
}

static enum fh_error w_colon(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  if (fh->state != FH_STATE_INTERPRET) {
    return FH_ERR_INVALID_STATE;
  }

  fh_setstate(fh, FH_STATE_COMPILE, FH_SUBSTATE_COLONNAME);

  if (fh->dict_top >= DICT_SIZE) {
    return FH_ERR_DICT_FULL;
  }
  fh->dict[fh->dict_top].start = fh->compile_top;
  fh->dict[fh->dict_top].handler = w_user_word;
  return FH_OK;
}

static enum fh_error w_semicolon(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  struct fh_instruction_s instr;

  if (fh->state != FH_STATE_COMPILE) {
    return FH_ERR_INVALID_STATE;
  }

  instr.kind = FH_INSTR_WORD;
  instr.data = CPLWORD_ENDWORD;
  TRY(fh_compile_put(fh, &instr, INSTR_SIZE));

  /* Return to interpret state */
  fh_setstate(fh, FH_STATE_INTERPRET, 0);
  fh->dict_top++;
  return FH_OK;
}

static enum fh_error w_dupe(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a = 0;
  TRY(ds_peek(fh, &a));
  TRY(ds_push(fh, a));
  return FH_OK;
}

static enum fh_error w_question_dupe(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a = 0;
  TRY(ds_peek(fh, &a));
  if (a) {
    TRY(ds_push(fh, a));
  }
  return FH_OK;
}

static enum fh_error w_two_dup(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a = 0;
  uint32_t b = 0;
  TRY(ds_peek_n(fh, &a, 0));
  TRY(ds_peek_n(fh, &b, 1));
  TRY(ds_push(fh, b));
  TRY(ds_push(fh, a));
  return FH_OK;
}

static enum fh_error w_drop(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a = 0;
  TRY(ds_pop(fh, &a));
  return FH_OK;
}

static enum fh_error w_two_drop(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a = 0;
  TRY(ds_pop(fh, &a));
  TRY(ds_pop(fh, &a));
  return FH_OK;
}

static enum fh_error w_swap(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  TRY(ds_roll(fh, 1));
  return FH_OK;
}

static enum fh_error w_two_swap(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  if (fh->data_stack_top < 4) {
    LOG("DS two-swap UNDERFLOW");
    return FH_ERR_DS_UNDERFLOW;
  }

  uint32_t n = fh->data_stack_top - 4;
  uint32_t a = fh->data_stack[n];
  uint32_t b = fh->data_stack[n + 1];
  fh->data_stack[n] = fh->data_stack[n + 2];
  fh->data_stack[n + 1] = fh->data_stack[n + 3];
  fh->data_stack[n + 2] = a;
  fh->data_stack[n + 3] = b;
  return FH_OK;
}

static enum fh_error w_rot(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  TRY(ds_roll(fh, 2));
  return FH_OK;
}

static enum fh_error w_over(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a = 0;
  TRY(ds_peek_n(fh, &a, 1));
  TRY(ds_push(fh, a));
  return FH_OK;
}

static enum fh_error w_two_over(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a = 0;
  uint32_t b = 0;
  TRY(ds_peek_n(fh, &a, 2));
  TRY(ds_peek_n(fh, &b, 3));
  TRY(ds_push(fh, b));
  TRY(ds_push(fh, a));
  return FH_OK;
}

static enum fh_error w_tuck(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a = 0;
  uint32_t b = 0;
  TRY(ds_pop(fh, &a));
  TRY(ds_pop(fh, &b));
  TRY(ds_push(fh, a));
  TRY(ds_push(fh, b));
  TRY(ds_push(fh, a));
  return FH_OK;
}

static enum fh_error w_pick(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t nth = 0;
  uint32_t a = 0;
  TRY(ds_pop(fh, &nth));
  TRY(ds_peek_n(fh, &a, nth));
  TRY(ds_push(fh, a));
  return FH_OK;
}

static enum fh_error w_roll(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t n = 0;
  TRY(ds_pop(fh, &n));
  TRY(ds_roll(fh, n));
  return FH_OK;
}

static enum fh_error w_to_r(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a;
  TRY(ds_pop(fh, &a));
  TRY(rs_push(fh, a));
  return FH_OK;
}

static enum fh_error w_two_to_r(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a;
  uint32_t b;
  TRY(ds_pop(fh, &a));
  TRY(ds_pop(fh, &b));
  TRY(rs_push(fh, b));
  TRY(rs_push(fh, a));
  return FH_OK;
}

static enum fh_error w_two_r_from(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a;
  uint32_t b;
  TRY(rs_pop(fh, &a));
  TRY(rs_pop(fh, &b));
  TRY(ds_push(fh, b));
  TRY(ds_push(fh, a));
  return FH_OK;
}

static enum fh_error w_two_r_fetch(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a;
  uint32_t b;
  TRY(rs_peek_n(fh, &a, 0));
  TRY(rs_peek_n(fh, &b, 1));
  TRY(ds_push(fh, b));
  TRY(ds_push(fh, a));
  return FH_OK;
}

static enum fh_error w_r_from(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a;
  TRY(rs_pop(fh, &a));
  TRY(ds_push(fh, a));
  return FH_OK;
}

static enum fh_error w_r_fetch(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a;
  TRY(rs_peek(fh, &a));
  TRY(ds_push(fh, a));
  return FH_OK;
}

static enum fh_error w_dot(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a = 0;
  TRY(ds_pop(fh, &a));

  FHPRINT("%d ", (int32_t) a);
  return FH_OK;
}

static enum fh_error w_type(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t count = 0, addr = 0;
  TRY(ds_pop(fh, &count));
  TRY(ds_pop(fh, &addr));

  FHPRINT("%.*s", count, &fh->heap[addr]);
  return FH_OK;
}

static enum fh_error wp_putc(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) fh;
  FHPRINT("%c", w->param);
  return FH_OK;
}

static enum fh_error w_space(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  (void) fh;
  FHPRINT(" ");
  return FH_OK;
}

static enum fh_error w_dump(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  (void) fh;

  FHPRINT("DS ");
  for (int i = 0; i < fh->data_stack_top; i++) {
    FHPRINT("%d ", fh->data_stack[i]);
  }

  FHPRINT("\nRS ");
  for (int i = 0; i < fh->return_stack_top; i++) {
    FHPRINT("%d ", fh->return_stack[i]);
  }

  FHPRINT("\n");
  return FH_OK;
}

static enum fh_error w_abort(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;

  fh->data_stack_top = 0;
  fh->return_stack_top = 0;
  fh_setstate(fh, FH_STATE_QUIT, 0);

  return FH_OK;
}

static enum fh_error w_quit(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;

  fh->return_stack_top = 0;
  fh_setstate(fh, FH_STATE_QUIT, 0);

  return FH_OK;
}

static enum fh_error w_exit(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;

  fh_setsubstate(fh, FH_SUBSTATE_EXIT);

  return FH_OK;
}

static enum fh_error w_s_quote(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  fh_setsubstate(fh, FH_SUBSTATE_SQUOTE);
  return FH_OK;
}

static enum fh_error w_dot_quote(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  fh_setsubstate(fh, FH_SUBSTATE_DOTQUOTE);
  return FH_OK;
}

static enum fh_error w_backslash(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  fh_setsubstate(fh, FH_SUBSTATE_LINECOMMENT);
  return FH_OK;
}

static enum fh_error w_paren(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  fh_setsubstate(fh, FH_SUBSTATE_PARENCOMMENT);
  return FH_OK;
}

static enum fh_error w_bye(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  fh_setstate(fh, FH_STATE_SHUTDOWN, 0);
  return FH_OK;
}

static enum fh_error wp_setbase(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  fh_setbase(fh, w->param);
  return FH_OK;
}

static enum fh_error w_emit(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t a;
  TRY(ds_pop(fh, &a));

  char buf[5];
  int num = utf8_encode(buf, a);
  FHPRINT("%.*s", num, buf);
  return FH_OK;
}

static enum fh_error wp_const(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  enum fh_error rv;
  TRY(ds_push(fh, w->param));
  return FH_OK;
}

static enum fh_error w_depth(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  TRY(ds_push(fh, w->param));
  return FH_OK;
}

static enum fh_error w_fetch(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t addr = 0;
  TRY(ds_pop(fh, &addr));
  uint32_t val = 0;
  TRY(fh_fetch(fh, addr, &val));
  TRY(ds_push(fh, val));
  return FH_OK;
}

static enum fh_error w_store(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t addr = 0;
  TRY(ds_pop(fh, &addr));
  uint32_t val = 0;
  TRY(ds_pop(fh, &val));

  TRY(fh_store(fh, addr, val));
  return FH_OK;
}

static enum fh_error w_two_store(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t addr = 0;
  TRY(ds_pop(fh, &addr));
  uint32_t a = 0, b = 0;
  TRY(ds_pop(fh, &a));
  TRY(ds_pop(fh, &b));

  TRY(fh_store(fh, addr, a));
  TRY(fh_store(fh, addr + CELL, b));
  return FH_OK;
}

static enum fh_error w_two_fetch(struct fh_thread_s *fh, const struct fh_word_s *w)
{
  (void) w;
  enum fh_error rv;
  uint32_t addr = 0;
  TRY(ds_pop(fh, &addr));
  uint32_t a = 0, b = 0;
  TRY(fh_fetch(fh, addr, &a));
  TRY(fh_fetch(fh, addr + CELL, &b));
  TRY(ds_push(fh, b));
  TRY(ds_push(fh, a));
  return FH_OK;
}

/** Add pointers to built-in word handlers to a runtime struct */
enum fh_error register_builtin_words(struct fh_thread_s *fh)
{
  struct name_and_handler {
    const char *name;
    word_exec_t handler;
    bool immediate;
    uint32_t param;
  };

  const struct name_and_handler builtins[] = {
      {"s\"",     w_s_quote,         1, 0},
      {".\"",     w_dot_quote,       1, 0},
      /* Compiler control words */
      {"bye",     w_bye,             0, 0},
      /* Pointers */
      {"@",       w_fetch,           0, 0},
      {"!",       w_store,           0, 0},
      {"2!",      w_two_store,       0, 0},
      {"2@",      w_two_fetch,       0, 0},
      // TODO +!
      // TODO pictured numbers (#)
      // TODO tick
      // TODO comma
      // TODO >BODY, >IN, >NUMBER
      /* Arithmetics */
      {"decimal", wp_setbase,        0, 10},
      {"hex",     wp_setbase,        0, 16},
      {"base",    wp_const,          0, MAGICADDR_BASE},
      {"depth",   w_depth,           0, 0},
      {"+",       w_plus,            0, 0},
      {"-",       w_minus,           0, 0},
      {"*",       w_star,            0, 0},
      {"*/",      w_star_slash,      0, 0},
      // TODO */mod
      {"/",       w_slash,           0, 0},
      {"/mod",    w_slash_mod,       0, 0},
      {"0<",      w_zero_less,       0, 0},
      {"0=",      w_zero_equals,     0, 0},
      {"0<>",     w_zero_not_equals, 0, 0},
      {"0>",      w_zero_greater,    0, 0},
      {"<",       w_less,            0, 0},
      {"=",       w_equals,          0, 0},
      {"<>",      w_not_equals,      0, 0},
      {">",       w_greater,         0, 0},
      {"1+",      wp_add,            0, 1},
      {"char+",   wp_add,            0, 1},
      {"1-",      wp_add,            0, -1},
      {"2+",      wp_add,            0, 2},
      {"2-",      wp_add,            0, -2},
      {"2*",      wp_mul,            0, 2},
      {"chars",   wp_mul,            0, 1},
      {"2/",      wp_div,            0, 2},
      {"cells",   wp_mul,            0, CELL},
      {"cell+",   wp_add,            0, CELL},
      /* Stack manip */
      {"drop",    w_drop,            0, 0},
      {"dup",     w_dupe,            0, 0},
      {"?dup",    w_question_dupe,   0, 0},
      {"over",    w_over,            0, 0},
      {"swap",    w_swap,            0, 0},
      {"rot",     w_rot,             0, 0},
      {"tuck",    w_tuck,            0, 0},
      {"pick",    w_pick,            0, 0},
      {"roll",    w_roll,            0, 0},
      /* Double wide stack manip */
      {"2drop",   w_two_drop,        0, 0},
      {"2dup",    w_two_dup,         0, 0},
      {"2over",   w_two_over,        0, 0},
      {"2swap",   w_two_swap,        0, 0},
//      /* Return stack manip */
      {">r",      w_to_r,            0, 0},
      {"r>",      w_r_from,          0, 0},
      {"r@",      w_r_fetch,         0, 0},
//      /* Double wide return stack manip */
      {"2>r",     w_two_to_r,        0, 0},
      {"2r>",     w_two_r_from,      0, 0},
      {"2r@",     w_two_r_fetch,     0, 0},
      /* Printing */
      {".",       w_dot,             0, 0},
      {"type",    w_type,            0, 0},
      {"cr",      wp_putc,           0, '\n'},
      {"space",   wp_putc,           0, ' '},
      {"bl",      wp_const,          0, ' '},
      {"dump",    w_dump,            0, 0},
      {"emit",    w_emit,            0, 0},
      /* Control flow */
      {"abort",   w_abort,           0, 0},
      {"quit",    w_quit,            0, 0},
      {"exit",    w_exit,            0, 0},
      /* Syntax */
      {":",       w_colon,           0, 0},
      {";",       w_semicolon,       1, 0},
      {"\\",      w_backslash,       1, 0}, // line comment
      {"(",       w_paren,           1, 0}, // enclosed comment
      { /* end marker */ }
  };

  // foreach
  struct fh_word_s w;
  const struct name_and_handler *p = builtins;
  enum fh_error rv;
  while (p->handler) {
    strcpy(w.name, p->name);
    w.handler = p->handler;
    w.builtin = 1;
    w.immediate = p->immediate;
    w.param = p->param;
    rv = fh_add_word(&w, fh);
    if (rv != FH_OK) {
      return rv;
    }
    p++;
  }
  return FH_OK;
}