Exemple #1
0
static int parse_slice(jv array, jv slice, int* pstart, int* pend) {
  // Array slices
  int len = jv_array_length(jv_copy(array));
  jv start_jv = jv_object_get(jv_copy(slice), jv_string("start"));
  jv end_jv = jv_object_get(slice, jv_string("end"));
  if (jv_get_kind(start_jv) == JV_KIND_NULL) {
    jv_free(start_jv);
    start_jv = jv_number(0);
  }
  if (jv_get_kind(end_jv) == JV_KIND_NULL) {
    jv_free(end_jv);
    end_jv = jv_number(len);
  }
  if (jv_get_kind(start_jv) != JV_KIND_NUMBER ||
      jv_get_kind(end_jv) != JV_KIND_NUMBER) {
    jv_free(start_jv);
    jv_free(end_jv);
    return 0;
  } else {
    int start = (int)jv_number_value(start_jv);
    int end = (int)jv_number_value(end_jv);
    if (start < 0) start = len + start;
    if (end < 0) end = len + end;

    if (start < 0) start = 0;
    if (start > len) start = len;
    if (end > len) end = len;
    if (end < start) end = start;
    assert(0 <= start && start <= end && end <= len);
    *pstart = start;
    *pend = end;
    return 1;
  }
}
Exemple #2
0
// assumes keys is a sorted array
jv jv_dels(jv t, jv keys) {
  assert(jv_get_kind(keys) == JV_KIND_ARRAY);
  assert(jv_is_valid(t));
  
  if (jv_get_kind(t) == JV_KIND_NULL || jv_array_length(jv_copy(keys)) == 0) {
    // no change
  } else if (jv_get_kind(t) == JV_KIND_ARRAY) {
    // extract slices, they must be handled differently
    jv orig_keys = keys;
    keys = jv_array();
    jv new_array = jv_array();
    jv starts = jv_array(), ends = jv_array();
    jv_array_foreach(orig_keys, i, key) {
      if (jv_get_kind(key) == JV_KIND_NUMBER) {
        keys = jv_array_append(keys, key);
      } else if (jv_get_kind(key) == JV_KIND_OBJECT) {
        int start, end;
        if (parse_slice(t, key, &start, &end)) {
          starts = jv_array_append(starts, jv_number(start));
          ends = jv_array_append(ends, jv_number(end));
        } else {
          jv_free(new_array);
          jv_free(key);
          new_array = jv_invalid_with_msg(jv_string_fmt("Start and end indices of an array slice must be numbers"));
          goto arr_out;
        }
      } else {
        jv_free(new_array);
        new_array = jv_invalid_with_msg(jv_string_fmt("Cannot delete %s element of array",
                                                      jv_kind_name(jv_get_kind(key))));
        jv_free(key);
        goto arr_out;
      }
    }

    int kidx = 0;
    jv_array_foreach(t, i, elem) {
      int del = 0;
      while (kidx < jv_array_length(jv_copy(keys))) {
        int delidx = (int)jv_number_value(jv_array_get(jv_copy(keys), kidx));
        if (i == delidx) {
          del = 1;
        }
        if (i < delidx) {
          break;
        }
        kidx++;
      }
      for (int sidx=0; !del && sidx<jv_array_length(jv_copy(starts)); sidx++) {
        if ((int)jv_number_value(jv_array_get(jv_copy(starts), sidx)) <= i &&
            i < (int)jv_number_value(jv_array_get(jv_copy(ends), sidx))) {
          del = 1;
        }
      }
      if (!del)
        new_array = jv_array_append(new_array, elem);
      else
        jv_free(elem);
    }
Exemple #3
0
static void f_length(jv input[], jv output[]) {
  if (jv_get_kind(input[0]) == JV_KIND_ARRAY) {
    output[0] = jv_number(jv_array_length(input[0]));
  } else if (jv_get_kind(input[0]) == JV_KIND_OBJECT) {
    output[0] = jv_number(jv_object_length(input[0]));
  } else if (jv_get_kind(input[0]) == JV_KIND_STRING) {
    output[0] = jv_number(jv_string_length(input[0]));
  } else {
    output[0] = jv_invalid_with_msg(jv_string_fmt("Cannot get the length of %s",
                                                  jv_kind_name(jv_get_kind(input[0]))));
    jv_free(input[0]);
  }
}
Exemple #4
0
static void f_minus(jv input[], jv output[]) {
  jv_free(input[0]);
  jv a = input[2];
  jv b = input[1];
  if (jv_get_kind(a) == JV_KIND_NUMBER && jv_get_kind(b) == JV_KIND_NUMBER) {
    output[0] = jv_number(jv_number_value(a) - jv_number_value(b));
  } else if (jv_get_kind(a) == JV_KIND_ARRAY && jv_get_kind(b) == JV_KIND_ARRAY) {
    jv out = jv_array();
    for (int i=0; i<jv_array_length(jv_copy(a)); i++) {
      jv x = jv_array_get(jv_copy(a), i);
      int include = 1;
      for (int j=0; j<jv_array_length(jv_copy(b)); j++) {
        if (jv_equal(jv_copy(x), jv_array_get(jv_copy(b), j))) {
          include = 0;
          break;
        }
      }
      if (include)
        out = jv_array_append(out, jv_copy(x));
      jv_free(x);
    }
    jv_free(a);
    jv_free(b);
    output[0] = out;
  } else {
    output[0] = jv_invalid_with_msg(jv_string_fmt("Attempted to subtract %s and %s",
                                                  jv_kind_name(jv_get_kind(a)),
                                                  jv_kind_name(jv_get_kind(b))));
    jv_free(a);
    jv_free(b);
  }
}
Exemple #5
0
static jv f_negate(jv input) {
  if (jv_get_kind(input) != JV_KIND_NUMBER) {
    return type_error(input, "cannot be negated");
  }
  jv ret = jv_number(-jv_number_value(input));
  jv_free(input);
  return ret;
}
Exemple #6
0
static jv f_sqrt(jv input) {
  if (jv_get_kind(input) != JV_KIND_NUMBER) {
    return type_error(input, "has no square root");
  }
  jv ret = jv_number(sqrt(jv_number_value(input)));
  jv_free(input);
  return ret;
}
Exemple #7
0
static int parse_slice(jv j, jv slice, int* pstart, int* pend) {
  // Array slices
  jv start_jv = jv_object_get(jv_copy(slice), jv_string("start"));
  jv end_jv = jv_object_get(slice, jv_string("end"));
  if (jv_get_kind(start_jv) == JV_KIND_NULL) {
    jv_free(start_jv);
    start_jv = jv_number(0);
  }
  int len;
  if (jv_get_kind(j) == JV_KIND_ARRAY)
    len = jv_array_length(jv_copy(j));
  else
    len = jv_string_length_codepoints(jv_copy(j));
  if (jv_get_kind(end_jv) == JV_KIND_NULL) {
    jv_free(end_jv);
    end_jv = jv_number(len);
  }
  if (jv_get_kind(start_jv) != JV_KIND_NUMBER ||
      jv_get_kind(end_jv) != JV_KIND_NUMBER) {
    jv_free(start_jv);
    jv_free(end_jv);
    return 0;
  } else {
    double dstart = jv_number_value(start_jv);
    double dend = jv_number_value(end_jv);
    if (dstart < 0) dstart += len;
    if (dend < 0) dend += len;
    if (dstart < 0) dstart = 0;
    if (dstart > len) dstart = len;

    int start = (int)dstart;
    int end = (dend > len) ? len : (int)dend;
    // Ends are exclusive but e.g. 1 < 1.5 so :1.5 should be :2 not :1
    if(end < dend) end += 1;

    if (end > len) end = len;
    if (end < start) end = start;
    assert(0 <= start && start <= end && end <= len);
    *pstart = start;
    *pend = end;
    return 1;
  }
}
Exemple #8
0
static void f_divide(jv input[], jv output[]) {
  jv_free(input[0]);
  jv a = input[2];
  jv b = input[1];
  if (jv_get_kind(a) == JV_KIND_NUMBER && jv_get_kind(b) == JV_KIND_NUMBER) {
    output[0] = jv_number(jv_number_value(a) / jv_number_value(b));
  } else {
    output[0] = jv_invalid_with_msg(jv_string_fmt("Attempted to divide %s by %s",
                                                  jv_kind_name(jv_get_kind(a)),
                                                  jv_kind_name(jv_get_kind(b))));
    jv_free(a);
    jv_free(b);
  }  
}
Exemple #9
0
static jv f_minus(jv input, jv a, jv b) {
  jv_free(input);
  if (jv_get_kind(a) == JV_KIND_NUMBER && jv_get_kind(b) == JV_KIND_NUMBER) {
    return jv_number(jv_number_value(a) - jv_number_value(b));
  } else if (jv_get_kind(a) == JV_KIND_ARRAY && jv_get_kind(b) == JV_KIND_ARRAY) {
    jv out = jv_array();
    jv_array_foreach(a, i, x) {
      int include = 1;
      jv_array_foreach(b, j, y) {
        if (jv_equal(jv_copy(x), y)) {
          include = 0;
          break;
        }
      }
      if (include)
        out = jv_array_append(out, jv_copy(x));
      jv_free(x);
    }
Exemple #10
0
static jv f_plus(jv input, jv a, jv b) {
  jv_free(input);
  if (jv_get_kind(a) == JV_KIND_NULL) {
    jv_free(a);
    return b;
  } else if (jv_get_kind(b) == JV_KIND_NULL) {
    jv_free(b);
    return a;
  } else if (jv_get_kind(a) == JV_KIND_NUMBER && jv_get_kind(b) == JV_KIND_NUMBER) {
    return jv_number(jv_number_value(a) + 
                     jv_number_value(b));
  } else if (jv_get_kind(a) == JV_KIND_STRING && jv_get_kind(b) == JV_KIND_STRING) {
    return jv_string_concat(a, b);
  } else if (jv_get_kind(a) == JV_KIND_ARRAY && jv_get_kind(b) == JV_KIND_ARRAY) {
    return jv_array_concat(a, b);
  } else if (jv_get_kind(a) == JV_KIND_OBJECT && jv_get_kind(b) == JV_KIND_OBJECT) {
    return jv_object_merge(a, b);
  } else {
    return type_error2(a, b, "cannot be added");
  }
}
Exemple #11
0
static void f_plus(jv input[], jv output[]) {
  jv_free(input[0]);
  jv a = input[2];
  jv b = input[1];
  if (jv_get_kind(a) == JV_KIND_NUMBER && jv_get_kind(b) == JV_KIND_NUMBER) {
    output[0] = jv_number(jv_number_value(a) + 
                          jv_number_value(b));
  } else if (jv_get_kind(a) == JV_KIND_STRING && jv_get_kind(b) == JV_KIND_STRING) {
    output[0] = jv_string_concat(a, b);
  } else if (jv_get_kind(a) == JV_KIND_ARRAY && jv_get_kind(b) == JV_KIND_ARRAY) {
    output[0] = jv_array_concat(a, b);
  } else if (jv_get_kind(a) == JV_KIND_OBJECT && jv_get_kind(b) == JV_KIND_OBJECT) {
    output[0] = jv_object_merge(a, b);
  } else {
    output[0] = jv_invalid_with_msg(jv_string_fmt("Attempted to add %s and %s",
                                                  jv_kind_name(jv_get_kind(a)),
                                                  jv_kind_name(jv_get_kind(b))));
    jv_free(a);
    jv_free(b);
  }
}
Exemple #12
0
static void jv_test() {
  /// JSON parser regression tests
  {
    jv v = jv_parse("{\"a':\"12\"}");
    assert(jv_get_kind(v) == JV_KIND_INVALID);
    v = jv_invalid_get_msg(v);
    assert(strcmp(jv_string_value(v), "Expected separator between values at line 1, column 9 (while parsing '{\"a':\"12\"}')") == 0);
    jv_free(v);
  }
  /// Arrays and numbers
  {
    jv a = jv_array();
    assert(jv_get_kind(a) == JV_KIND_ARRAY);
    assert(jv_array_length(jv_copy(a)) == 0);
    assert(jv_array_length(jv_copy(a)) == 0);
  
    a = jv_array_append(a, jv_number(42));
    assert(jv_array_length(jv_copy(a)) == 1);
    assert(jv_number_value(jv_array_get(jv_copy(a), 0)) == 42);

    jv a2 = jv_array_append(jv_array(), jv_number(42));
    assert(jv_equal(jv_copy(a), jv_copy(a)));
    assert(jv_equal(jv_copy(a2), jv_copy(a2)));
    assert(jv_equal(jv_copy(a), jv_copy(a2)));
    assert(jv_equal(jv_copy(a2), jv_copy(a)));
    jv_free(a2);

    a2 = jv_array_append(jv_array(), jv_number(19));
    assert(!jv_equal(jv_copy(a), jv_copy(a2)));
    assert(!jv_equal(jv_copy(a2), jv_copy(a)));
    jv_free(a2);


    assert(jv_get_refcnt(a) == 1);
    a = jv_array_append(a, jv_copy(a));
    assert(jv_get_refcnt(a) == 1);

    assert(jv_array_length(jv_copy(a)) == 2);
    assert(jv_number_value(jv_array_get(jv_copy(a), 0)) == 42);

    for (int i=0; i<10; i++) {
      jv subarray = jv_array_get(jv_copy(a), 1);
      assert(jv_get_kind(subarray) == JV_KIND_ARRAY);
      assert(jv_array_length(jv_copy(subarray)) == 1);
      assert(jv_number_value(jv_array_get(jv_copy(subarray), 0)) == 42);
      jv_free(subarray);
    }


    jv subarray = jv_array_get(jv_copy(a), 1);
    assert(jv_get_kind(subarray) == JV_KIND_ARRAY);
    assert(jv_array_length(jv_copy(subarray)) == 1);
    assert(jv_number_value(jv_array_get(jv_copy(subarray), 0)) == 42);

    jv sub2 = jv_copy(subarray);
    sub2 = jv_array_append(sub2, jv_number(19));

    assert(jv_get_kind(sub2) == JV_KIND_ARRAY);
    assert(jv_array_length(jv_copy(sub2)) == 2);
    assert(jv_number_value(jv_array_get(jv_copy(sub2), 0)) == 42);
    assert(jv_number_value(jv_array_get(jv_copy(sub2), 1)) == 19);

    assert(jv_get_kind(subarray) == JV_KIND_ARRAY);
    assert(jv_array_length(jv_copy(subarray)) == 1);
    assert(jv_number_value(jv_array_get(jv_copy(subarray), 0)) == 42);

    jv_free(subarray);

    void* before = sub2.u.ptr;
    sub2 = jv_array_append(sub2, jv_number(200));
    void* after = sub2.u.ptr;
    assert(before == after);
    jv_free(sub2);

    jv a3 = jv_array_append(jv_copy(a), jv_number(19));
    assert(jv_array_length(jv_copy(a3)) == 3);
    assert(jv_number_value(jv_array_get(jv_copy(a3), 0)) == 42);
    assert(jv_array_length(jv_array_get(jv_copy(a3), 1)) == 1);
    assert(jv_number_value(jv_array_get(jv_copy(a3), 2)) == 19);
    jv_free(a3);


    jv a4 = jv_array();
    a4 = jv_array_append(a4, jv_number(1));
    a4 = jv_array_append(a4, jv_number(2));
    jv a5 = jv_copy(a4);
    a4 = jv_array_append(a4, jv_number(3));
    a4 = jv_array_slice(a4, 0, 1);
    assert(jv_array_length(jv_copy(a4)) == 1);
    a4 = jv_array_append(a4, jv_number(4));
    assert(jv_array_length(jv_copy(a4)) == 2);
    assert(jv_array_length(jv_copy(a5)) == 2);
    jv_free(a4);
    jv_free(a5);


    assert(jv_array_length(jv_copy(a)) == 2);
    assert(jv_number_value(jv_array_get(jv_copy(a), 0)) == 42);
    assert(jv_array_length(jv_array_get(jv_copy(a), 1)) == 1);


    jv_dump(jv_copy(a), 0); printf("\n");
    jv_free(a);
  }


  /// Strings
  {
    assert(jv_equal(jv_string("foo"), jv_string_sized("foo", 3)));
    char nasty[] = "foo\0";
    jv shortstr = jv_string(nasty), longstr = jv_string_sized(nasty, sizeof(nasty));
    assert(jv_string_length_bytes(jv_copy(shortstr)) == (int)strlen(nasty));
    assert(jv_string_length_bytes(jv_copy(longstr)) == (int)sizeof(nasty));
    jv_free(shortstr);
    jv_free(longstr);

  
    char a1s[] = "hello", a2s[] = "hello", bs[] = "goodbye";
    jv a1 = jv_string(a1s), a2 = jv_string(a2s), b = jv_string(bs);
    assert(jv_equal(jv_copy(a1), jv_copy(a2)));
    assert(jv_equal(jv_copy(a2), jv_copy(a1)));
    assert(!jv_equal(jv_copy(a1), jv_copy(b)));
    
    assert(jv_string_hash(jv_copy(a1)) == jv_string_hash(jv_copy(a1)));
    assert(jv_string_hash(jv_copy(a1)) == jv_string_hash(jv_copy(a2)));
    assert(jv_string_hash(jv_copy(b)) != jv_string_hash(jv_copy(a1)));
    jv_free(a1);
    jv_free(a2);
    jv_free(b);

    assert(jv_equal(jv_string("hello42!"), jv_string_fmt("hello%d%s", 42, "!")));
    char big[20000];
    for (int i=0; i<(int)sizeof(big); i++) big[i] = 'a';
    big[sizeof(big)-1] = 0;
    jv str = jv_string_fmt("%s", big);
    assert(jv_string_length_bytes(jv_copy(str)) == sizeof(big) - 1);
    assert(!strcmp(big, jv_string_value(str)));
    jv_free(str);
  }

  /// Objects
  {
    jv o1 = jv_object();
    o1 = jv_object_set(o1, jv_string("foo"), jv_number(42));
    o1 = jv_object_set(o1, jv_string("bar"), jv_number(24));
    assert(jv_number_value(jv_object_get(jv_copy(o1), jv_string("foo"))) == 42);
    assert(jv_number_value(jv_object_get(jv_copy(o1), jv_string("bar"))) == 24);

    jv o2 = jv_object_set(jv_copy(o1), jv_string("foo"), jv_number(420));
    o2 = jv_object_set(o2, jv_string("bar"), jv_number(240));
    assert(jv_number_value(jv_object_get(jv_copy(o1), jv_string("foo"))) == 42);
    assert(jv_number_value(jv_object_get(jv_copy(o1), jv_string("bar"))) == 24);
    assert(jv_number_value(jv_object_get(jv_copy(o2), jv_string("foo"))) == 420);
    jv_free(o1);
    assert(jv_number_value(jv_object_get(jv_copy(o2), jv_string("bar"))) == 240);

    jv_dump(jv_copy(o2), 0); printf("\n");

    jv_free(o2);
  }

  /// Compile errors
  {
    jq_state *jq = jq_init();
    jq_compile_args(jq, "}", jv_array());
    jq_teardown(&jq);
  }
}
Exemple #13
0
jv jq_next(jq_state *jq) {
  jv cfunc_input[MAX_CFUNCTION_ARGS];

  jv_nomem_handler(jq->nomem_handler, jq->nomem_handler_data);

  uint16_t* pc = stack_restore(jq);
  assert(pc);

  int backtracking = !jq->initial_execution;
  jq->initial_execution = 0;
  while (1) {
    uint16_t opcode = *pc;

    if (jq->debug_trace_enabled) {
      dump_operation(frame_current(jq)->bc, pc);
      printf("\t");
      const struct opcode_description* opdesc = opcode_describe(opcode);
      stack_ptr param = 0;
      if (!backtracking) {
        int stack_in = opdesc->stack_in;
        if (stack_in == -1) stack_in = pc[1];
        int i;
        for (i=0; i<stack_in; i++) {
          if (i == 0) {
            param = jq->stk_top;
          } else {
            printf(" | ");
            param = *stack_block_next(&jq->stk, param);
          }
          if (!param) break;
          jv_dump(jv_copy(*(jv*)stack_block(&jq->stk, param)), 0);
          //printf("<%d>", jv_get_refcnt(param->val));
          //printf(" -- ");
          //jv_dump(jv_copy(jq->path), 0);
        }
      } else {
        printf("\t<backtracking>");
      }

      printf("\n");
    }

    if (backtracking) {
      opcode = ON_BACKTRACK(opcode);
      backtracking = 0;
    }
    pc++;

    switch (opcode) {
    default: assert(0 && "invalid instruction");

    case LOADK: {
      jv v = jv_array_get(jv_copy(frame_current(jq)->bc->constants), *pc++);
      assert(jv_is_valid(v));
      jv_free(stack_pop(jq));
      stack_push(jq, v);
      break;
    }

    case DUP: {
      jv v = stack_pop(jq);
      stack_push(jq, jv_copy(v));
      stack_push(jq, v);
      break;
    }

    case DUP2: {
      jv keep = stack_pop(jq);
      jv v = stack_pop(jq);
      stack_push(jq, jv_copy(v));
      stack_push(jq, keep);
      stack_push(jq, v);
      break;
    }

    case SUBEXP_BEGIN: {
      jv v = stack_pop(jq);
      stack_push(jq, jv_copy(v));
      stack_push(jq, v);
      jq->subexp_nest++;
      break;
    }

    case SUBEXP_END: {
      assert(jq->subexp_nest > 0);
      jq->subexp_nest--;
      jv a = stack_pop(jq);
      jv b = stack_pop(jq);
      stack_push(jq, a);
      stack_push(jq, b);
      break;
    }
      
    case POP: {
      jv_free(stack_pop(jq));
      break;
    }

    case APPEND: {
      jv v = stack_pop(jq);
      uint16_t level = *pc++;
      uint16_t vidx = *pc++;
      jv* var = frame_local_var(jq, vidx, level);
      assert(jv_get_kind(*var) == JV_KIND_ARRAY);
      *var = jv_array_append(*var, v);
      break;
    }

    case INSERT: {
      jv stktop = stack_pop(jq);
      jv v = stack_pop(jq);
      jv k = stack_pop(jq);
      jv objv = stack_pop(jq);
      assert(jv_get_kind(objv) == JV_KIND_OBJECT);
      if (jv_get_kind(k) == JV_KIND_STRING) {
        stack_push(jq, jv_object_set(objv, k, v));
        stack_push(jq, stktop);
      } else {
        print_error(jq, jv_invalid_with_msg(jv_string_fmt("Cannot use %s as object key",
                                                          jv_kind_name(jv_get_kind(k)))));
        jv_free(stktop);
        jv_free(v);
        jv_free(k);
        jv_free(objv);
        goto do_backtrack;
      }
      break;
    }

    case ON_BACKTRACK(RANGE):
    case RANGE: {
      uint16_t level = *pc++;
      uint16_t v = *pc++;
      jv* var = frame_local_var(jq, v, level);
      jv max = stack_pop(jq);
      if (jv_get_kind(*var) != JV_KIND_NUMBER ||
          jv_get_kind(max) != JV_KIND_NUMBER) {
        print_error(jq, jv_invalid_with_msg(jv_string_fmt("Range bounds must be numeric")));
        jv_free(max);
        goto do_backtrack;
      } else if (jv_number_value(jv_copy(*var)) >= jv_number_value(jv_copy(max))) {
        /* finished iterating */
        goto do_backtrack;
      } else {
        jv curr = jv_copy(*var);
        *var = jv_number(jv_number_value(*var) + 1);

        struct stack_pos spos = stack_get_pos(jq);
        stack_push(jq, jv_copy(max));
        stack_save(jq, pc - 3, spos);

        stack_push(jq, curr);
      }
      break;
    }

      // FIXME: loadv/storev may do too much copying/freeing
    case LOADV: {
      uint16_t level = *pc++;
      uint16_t v = *pc++;
      jv* var = frame_local_var(jq, v, level);
      if (jq->debug_trace_enabled) {
        printf("V%d = ", v);
        jv_dump(jv_copy(*var), 0);
        printf("\n");
      }
      jv_free(stack_pop(jq));
      stack_push(jq, jv_copy(*var));
      break;
    }

      // Does a load but replaces the variable with null
    case LOADVN: {
      uint16_t level = *pc++;
      uint16_t v = *pc++;
      jv* var = frame_local_var(jq, v, level);
      if (jq->debug_trace_enabled) {
        printf("V%d = ", v);
        jv_dump(jv_copy(*var), 0);
        printf("\n");
      }
      jv_free(stack_pop(jq));
      stack_push(jq, *var);
      *var = jv_null();
      break;
    }

    case STOREV: {
      uint16_t level = *pc++;
      uint16_t v = *pc++;
      jv* var = frame_local_var(jq, v, level);
      jv val = stack_pop(jq);
      if (jq->debug_trace_enabled) {
        printf("V%d = ", v);
        jv_dump(jv_copy(val), 0);
        printf("\n");
      }
      jv_free(*var);
      *var = val;
      break;
    }

    case PATH_BEGIN: {
      jv v = stack_pop(jq);
      stack_push(jq, jq->path);

      stack_save(jq, pc - 1, stack_get_pos(jq));

      stack_push(jq, jv_number(jq->subexp_nest));
      stack_push(jq, v);

      jq->path = jv_array();
      jq->subexp_nest = 0;
      break;
    }

    case PATH_END: {
      jv v = stack_pop(jq);
      jv_free(v); // discard value, only keep path

      int old_subexp_nest = (int)jv_number_value(stack_pop(jq));

      jv path = jq->path;
      jq->path = stack_pop(jq);

      struct stack_pos spos = stack_get_pos(jq);
      stack_push(jq, jv_copy(path));
      stack_save(jq, pc - 1, spos);

      stack_push(jq, path);
      jq->subexp_nest = old_subexp_nest;
      break;
    }

    case ON_BACKTRACK(PATH_BEGIN):
    case ON_BACKTRACK(PATH_END): {
      jv_free(jq->path);
      jq->path = stack_pop(jq);
      goto do_backtrack;
    }

    case INDEX:
    case INDEX_OPT: {
      jv t = stack_pop(jq);
      jv k = stack_pop(jq);
      path_append(jq, jv_copy(k));
      jv v = jv_get(t, k);
      if (jv_is_valid(v)) {
        stack_push(jq, v);
      } else {
        if (opcode == INDEX)
          print_error(jq, v);
        else
          jv_free(v);
        goto do_backtrack;
      }
      break;
    }


    case JUMP: {
      uint16_t offset = *pc++;
      pc += offset;
      break;
    }

    case JUMP_F: {
      uint16_t offset = *pc++;
      jv t = stack_pop(jq);
      jv_kind kind = jv_get_kind(t);
      if (kind == JV_KIND_FALSE || kind == JV_KIND_NULL) {
        pc += offset;
      }
      stack_push(jq, t); // FIXME do this better
      break;
    }

    case EACH: 
    case EACH_OPT: 
      stack_push(jq, jv_number(-1));
      // fallthrough
    case ON_BACKTRACK(EACH):
    case ON_BACKTRACK(EACH_OPT): {
      int idx = jv_number_value(stack_pop(jq));
      jv container = stack_pop(jq);

      int keep_going, is_last = 0;
      jv key, value;
      if (jv_get_kind(container) == JV_KIND_ARRAY) {
        if (opcode == EACH || opcode == EACH_OPT) idx = 0;
        else idx = idx + 1;
        int len = jv_array_length(jv_copy(container));
        keep_going = idx < len;
        is_last = idx == len - 1;
        if (keep_going) {
          key = jv_number(idx);
          value = jv_array_get(jv_copy(container), idx);
        }
      } else if (jv_get_kind(container) == JV_KIND_OBJECT) {
        if (opcode == EACH || opcode == EACH_OPT) idx = jv_object_iter(container);
        else idx = jv_object_iter_next(container, idx);
        keep_going = jv_object_iter_valid(container, idx);
        if (keep_going) {
          key = jv_object_iter_key(container, idx);
          value = jv_object_iter_value(container, idx);
        }
      } else {
        assert(opcode == EACH || opcode == EACH_OPT);
        if (opcode == EACH) {
          print_error(jq,
                      jv_invalid_with_msg(jv_string_fmt("Cannot iterate over %s",
                                                        jv_kind_name(jv_get_kind(container)))));
        }
        keep_going = 0;
      }

      if (!keep_going) {
        jv_free(container);
        goto do_backtrack;
      } else if (is_last) {
        // we don't need to make a backtrack point
        jv_free(container);
        path_append(jq, key);
        stack_push(jq, value);
      } else {
        struct stack_pos spos = stack_get_pos(jq);
        stack_push(jq, container);
        stack_push(jq, jv_number(idx));
        stack_save(jq, pc - 1, spos);
        path_append(jq, key);
        stack_push(jq, value);
      }
      break;
    }

    do_backtrack:
    case BACKTRACK: {
      pc = stack_restore(jq);
      if (!pc) {
        return jv_invalid();
      }
      backtracking = 1;
      break;
    }

    case FORK: {
      stack_save(jq, pc - 1, stack_get_pos(jq));
      pc++; // skip offset this time
      break;
    }

    case ON_BACKTRACK(FORK): {
      uint16_t offset = *pc++;
      pc += offset;
      break;
    }
      
    case CALL_BUILTIN: {
      int nargs = *pc++;
      jv top = stack_pop(jq);
      jv* in = cfunc_input;
      int i;
      in[0] = top;
      for (i = 1; i < nargs; i++) {
        in[i] = stack_pop(jq);
      }
      struct cfunction* function = &frame_current(jq)->bc->globals->cfunctions[*pc++];
      typedef jv (*func_1)(jv);
      typedef jv (*func_2)(jv,jv);
      typedef jv (*func_3)(jv,jv,jv);
      typedef jv (*func_4)(jv,jv,jv,jv);
      typedef jv (*func_5)(jv,jv,jv,jv,jv);
      switch (function->nargs) {
      case 1: top = ((func_1)function->fptr)(in[0]); break;
      case 2: top = ((func_2)function->fptr)(in[0], in[1]); break;
      case 3: top = ((func_3)function->fptr)(in[0], in[1], in[2]); break;
      case 4: top = ((func_4)function->fptr)(in[0], in[1], in[2], in[3]); break;
      case 5: top = ((func_5)function->fptr)(in[0], in[1], in[2], in[3], in[4]); break;
      default: return jv_invalid_with_msg(jv_string("Function takes too many arguments"));
      }
      
      if (jv_is_valid(top)) {
        stack_push(jq, top);
      } else {
        print_error(jq, top);
        goto do_backtrack;
      }
      break;
    }

    case CALL_JQ: {
      jv input = stack_pop(jq);
      uint16_t nclosures = *pc++;
      uint16_t* retaddr = pc + 2 + nclosures*2;
      struct frame* new_frame = frame_push(jq, make_closure(jq, pc),
                                           pc + 2, nclosures);
      new_frame->retdata = jq->stk_top;
      new_frame->retaddr = retaddr;
      pc = new_frame->bc->code;
      stack_push(jq, input);
      break;
    }

    case RET: {
      jv value = stack_pop(jq);
      assert(jq->stk_top == frame_current(jq)->retdata);
      uint16_t* retaddr = frame_current(jq)->retaddr;
      if (retaddr) {
        // function return
        pc = retaddr;
        frame_pop(jq);
      } else {
        // top-level return, yielding value
        struct stack_pos spos = stack_get_pos(jq);
        stack_push(jq, jv_null());
        stack_save(jq, pc - 1, spos);
        return value;
      }
      stack_push(jq, value);
      break;
    }
    case ON_BACKTRACK(RET): {
      // resumed after top-level return
      goto do_backtrack;
    }
    }
  }
}
Exemple #14
0
static void jv_test() {
  /// Arrays and numbers
  {
    jv a = jv_array();
    assert(jv_get_kind(a) == JV_KIND_ARRAY);
    assert(jv_array_length(jv_copy(a)) == 0);
    assert(jv_array_length(jv_copy(a)) == 0);
  
    a = jv_array_append(a, jv_number(42));
    assert(jv_array_length(jv_copy(a)) == 1);
    assert(jv_number_value(jv_array_get(jv_copy(a), 0)) == 42);

    jv a2 = jv_array_append(jv_array(), jv_number(42));
    assert(jv_equal(jv_copy(a), jv_copy(a)));
    assert(jv_equal(jv_copy(a2), jv_copy(a2)));
    assert(jv_equal(jv_copy(a), jv_copy(a2)));
    assert(jv_equal(jv_copy(a2), jv_copy(a)));
    jv_free(a2);

    a2 = jv_array_append(jv_array(), jv_number(19));
    assert(!jv_equal(jv_copy(a), jv_copy(a2)));
    assert(!jv_equal(jv_copy(a2), jv_copy(a)));
    jv_free(a2);


    assert(a.val.nontrivial.ptr->count == 1);
    a = jv_array_append(a, jv_copy(a));
    assert(a.val.nontrivial.ptr->count == 1);

    assert(jv_array_length(jv_copy(a)) == 2);
    assert(jv_number_value(jv_array_get(jv_copy(a), 0)) == 42);

    for (int i=0; i<10; i++) {
      jv subarray = jv_array_get(jv_copy(a), 1);
      assert(jv_get_kind(subarray) == JV_KIND_ARRAY);
      assert(jv_array_length(jv_copy(subarray)) == 1);
      assert(jv_number_value(jv_array_get(jv_copy(subarray), 0)) == 42);
      jv_free(subarray);
    }


    jv subarray = jv_array_get(jv_copy(a), 1);
    assert(jv_get_kind(subarray) == JV_KIND_ARRAY);
    assert(jv_array_length(jv_copy(subarray)) == 1);
    assert(jv_number_value(jv_array_get(jv_copy(subarray), 0)) == 42);

    jv sub2 = jv_copy(subarray);
    sub2 = jv_array_append(sub2, jv_number(19));

    assert(jv_get_kind(sub2) == JV_KIND_ARRAY);
    assert(jv_array_length(jv_copy(sub2)) == 2);
    assert(jv_number_value(jv_array_get(jv_copy(sub2), 0)) == 42);
    assert(jv_number_value(jv_array_get(jv_copy(sub2), 1)) == 19);

    assert(jv_get_kind(subarray) == JV_KIND_ARRAY);
    assert(jv_array_length(jv_copy(subarray)) == 1);
    assert(jv_number_value(jv_array_get(jv_copy(subarray), 0)) == 42);

    jv_free(subarray);

    void* before = sub2.val.nontrivial.ptr;
    sub2 = jv_array_append(sub2, jv_number(200));
    void* after = sub2.val.nontrivial.ptr;
    assert(before == after);
    jv_free(sub2);

    jv a3 = jv_array_append(jv_copy(a), jv_number(19));
    assert(jv_array_length(jv_copy(a3)) == 3);
    assert(jv_number_value(jv_array_get(jv_copy(a3), 0)) == 42);
    assert(jv_array_length(jv_array_get(jv_copy(a3), 1)) == 1);
    assert(jv_number_value(jv_array_get(jv_copy(a3), 2)) == 19);
    jv_free(a3);


    jv a4 = jv_array();
    a4 = jv_array_append(a4, jv_number(1));
    a4 = jv_array_append(a4, jv_number(2));
    jv a5 = jv_copy(a4);
    a4 = jv_array_append(a4, jv_number(3));
    a4 = jv_array_slice(a4, 0, 1);
    assert(jv_array_length(jv_copy(a4)) == 1);
    a4 = jv_array_append(a4, jv_number(4));
    assert(jv_array_length(a4) == 2);
    assert(jv_array_length(a5) == 2);


    assert(jv_array_length(jv_copy(a)) == 2);
    assert(jv_number_value(jv_array_get(jv_copy(a), 0)) == 42);
    assert(jv_array_length(jv_array_get(jv_copy(a), 1)) == 1);


    jv_dump(jv_copy(a), 0); printf("\n");
    jv_free(a);
  }


  /// Strings
  {
    assert(jv_equal(jv_string("foo"), jv_string_sized("foo", 3)));
    char nasty[] = "foo\0";
    jv shortstr = jv_string(nasty), longstr = jv_string_sized(nasty, sizeof(nasty));
    assert(jv_string_length_bytes(shortstr) == (int)strlen(nasty));
    assert(jv_string_length_bytes(longstr) == (int)sizeof(nasty));

  
    char a1s[] = "hello", a2s[] = "hello", bs[] = "goodbye";
    jv a1 = jv_string(a1s), a2 = jv_string(a2s), b = jv_string(bs);
    assert(jv_equal(jv_copy(a1), jv_copy(a2)));
    assert(jv_equal(jv_copy(a2), jv_copy(a1)));
    assert(!jv_equal(jv_copy(a1), jv_copy(b)));
    
    assert(jv_string_hash(jv_copy(a1)) == jv_string_hash(jv_copy(a1)));
    assert(jv_string_hash(jv_copy(a1)) == jv_string_hash(jv_copy(a2)));
    assert(jv_string_hash(jv_copy(b)) != jv_string_hash(jv_copy(a1)));
    jv_free(a1);
    jv_free(a2);
    jv_free(b);

    assert(jv_equal(jv_string("hello42!"), jv_string_fmt("hello%d%s", 42, "!")));
    char big[20000];
    for (int i=0; i<(int)sizeof(big); i++) big[i] = 'a';
    big[sizeof(big)-1] = 0;
    jv str = jv_string_fmt("%s", big);
    assert(jv_string_length_bytes(jv_copy(str)) == sizeof(big) - 1);
    assert(!strcmp(big, jv_string_value(str)));
    jv_free(str);
  }

  /// Objects
  {
    jv o1 = jv_object();
    o1 = jv_object_set(o1, jv_string("foo"), jv_number(42));
    o1 = jv_object_set(o1, jv_string("bar"), jv_number(24));
    assert(jv_number_value(jv_object_get(jv_copy(o1), jv_string("foo"))) == 42);
    assert(jv_number_value(jv_object_get(jv_copy(o1), jv_string("bar"))) == 24);

    jv o2 = jv_object_set(jv_copy(o1), jv_string("foo"), jv_number(420));
    o2 = jv_object_set(o2, jv_string("bar"), jv_number(240));
    assert(jv_number_value(jv_object_get(jv_copy(o1), jv_string("foo"))) == 42);
    assert(jv_number_value(jv_object_get(jv_copy(o1), jv_string("bar"))) == 24);
    assert(jv_number_value(jv_object_get(jv_copy(o2), jv_string("foo"))) == 420);
    jv_free(o1);
    assert(jv_number_value(jv_object_get(jv_copy(o2), jv_string("bar"))) == 240);

    jv_dump(jv_copy(o2), 0); printf("\n");

    jv_free(o2);
  }
}
Exemple #15
0
jv jq_next(jq_state *jq) {
  jv cfunc_input[MAX_CFUNCTION_ARGS];

  uint16_t* pc = stack_restore(jq);
  assert(pc);

  int backtracking = !jq->initial_execution;
  jq->initial_execution = 0;
  while (1) {
    uint16_t opcode = *pc;

    if (jq->debug_trace_enabled) {
      dump_operation(frame_current_bytecode(&jq->frame_stk), pc);
      printf("\t");
      const struct opcode_description* opdesc = opcode_describe(opcode);
      data_stk_elem* param = 0;
      int stack_in = opdesc->stack_in;
      if (stack_in == -1) stack_in = pc[1];
      for (int i=0; i<stack_in; i++) {
        if (i == 0) {
          param = forkable_stack_peek(&jq->data_stk);
        } else {
          printf(" | ");
          param = forkable_stack_peek_next(&jq->data_stk, param);
        }
        if (!param) break;
        jv_dump(jv_copy(param->val), 0);
        //printf("<%d>", jv_get_refcnt(param->val));
        //printf(" -- ");
        //jv_dump(jv_copy(jq->path), 0);
      }

      if (backtracking) printf("\t<backtracking>");

      printf("\n");
    }
    if (backtracking) {
      opcode = ON_BACKTRACK(opcode);
      backtracking = 0;
    }
    pc++;

    switch (opcode) {
    default: assert(0 && "invalid instruction");

    case LOADK: {
      jv v = jv_array_get(jv_copy(frame_current_bytecode(&jq->frame_stk)->constants), *pc++);
      assert(jv_is_valid(v));
      jv_free(stack_pop(jq));
      stack_push(jq, v);
      break;
    }

    case DUP: {
      jv v = stack_pop(jq);
      stack_push(jq, jv_copy(v));
      stack_push(jq, v);
      break;
    }

    case DUP2: {
      jv keep = stack_pop(jq);
      jv v = stack_pop(jq);
      stack_push(jq, jv_copy(v));
      stack_push(jq, keep);
      stack_push(jq, v);
      break;
    }

    case SUBEXP_BEGIN: {
      jv v = stack_pop(jq);
      stack_push(jq, jv_copy(v));
      stack_push(jq, v);
      jq->subexp_nest++;
      break;
    }

    case SUBEXP_END: {
      assert(jq->subexp_nest > 0);
      jq->subexp_nest--;
      jv a = stack_pop(jq);
      jv b = stack_pop(jq);
      stack_push(jq, a);
      stack_push(jq, b);
      break;
    }
      
    case POP: {
      jv_free(stack_pop(jq));
      break;
    }

    case APPEND: {
      jv v = stack_pop(jq);
      uint16_t level = *pc++;
      uint16_t vidx = *pc++;
      frame_ptr fp = frame_get_level(&jq->frame_stk, frame_current(&jq->frame_stk), level);
      jv* var = frame_local_var(fp, vidx);
      assert(jv_get_kind(*var) == JV_KIND_ARRAY);
      *var = jv_array_append(*var, v);
      break;
    }

    case INSERT: {
      jv stktop = stack_pop(jq);
      jv v = stack_pop(jq);
      jv k = stack_pop(jq);
      jv objv = stack_pop(jq);
      assert(jv_get_kind(objv) == JV_KIND_OBJECT);
      if (jv_get_kind(k) == JV_KIND_STRING) {
        stack_push(jq, jv_object_set(objv, k, v));
        stack_push(jq, stktop);
      } else {
        print_error(jv_invalid_with_msg(jv_string_fmt("Cannot use %s as object key",
                                                      jv_kind_name(jv_get_kind(k)))));
        jv_free(stktop);
        jv_free(v);
        jv_free(k);
        jv_free(objv);
        goto do_backtrack;
      }
      break;
    }

    case ON_BACKTRACK(RANGE):
    case RANGE: {
      uint16_t level = *pc++;
      uint16_t v = *pc++;
      frame_ptr fp = frame_get_level(&jq->frame_stk, frame_current(&jq->frame_stk), level);
      jv* var = frame_local_var(fp, v);
      jv max = stack_pop(jq);
      if (jv_get_kind(*var) != JV_KIND_NUMBER ||
          jv_get_kind(max) != JV_KIND_NUMBER) {
        print_error(jv_invalid_with_msg(jv_string_fmt("Range bounds must be numeric")));
        jv_free(max);
        goto do_backtrack;
      } else if (jv_number_value(jv_copy(*var)) >= jv_number_value(jv_copy(max))) {
        /* finished iterating */
        goto do_backtrack;
      } else {
        jv curr = jv_copy(*var);
        *var = jv_number(jv_number_value(*var) + 1);

        stack_save(jq, pc - 3);
        stack_push(jq, jv_copy(max));
        stack_switch(jq);
        stack_push(jq, curr);
      }
      break;
    }

      // FIXME: loadv/storev may do too much copying/freeing
    case LOADV: {
      uint16_t level = *pc++;
      uint16_t v = *pc++;
      frame_ptr fp = frame_get_level(&jq->frame_stk, frame_current(&jq->frame_stk), level);
      jv* var = frame_local_var(fp, v);
      if (jq->debug_trace_enabled) {
        printf("V%d = ", v);
        jv_dump(jv_copy(*var), 0);
        printf("\n");
      }
      jv_free(stack_pop(jq));
      stack_push(jq, jv_copy(*var));
      break;
    }

    case STOREV: {
      uint16_t level = *pc++;
      uint16_t v = *pc++;
      frame_ptr fp = frame_get_level(&jq->frame_stk, frame_current(&jq->frame_stk), level);
      jv* var = frame_local_var(fp, v);
      jv val = stack_pop(jq);
      if (jq->debug_trace_enabled) {
        printf("V%d = ", v);
        jv_dump(jv_copy(val), 0);
        printf("\n");
      }
      jv_free(*var);
      *var = val;
      break;
    }

    case PATH_BEGIN: {
      jv v = stack_pop(jq);
      stack_push(jq, jq->path);

      stack_save(jq, pc - 1);
      stack_switch(jq);

      stack_push(jq, jv_number(jq->subexp_nest));
      stack_push(jq, v);

      jq->path = jv_array();
      jq->subexp_nest = 0;
      break;
    }

    case PATH_END: {
      jv v = stack_pop(jq);
      jv_free(v); // discard value, only keep path

      int old_subexp_nest = (int)jv_number_value(stack_pop(jq));

      jv path = jq->path;
      jq->path = stack_pop(jq);

      stack_save(jq, pc - 1);
      stack_push(jq, jv_copy(path));
      stack_switch(jq);

      stack_push(jq, path);
      jq->subexp_nest = old_subexp_nest;
      break;
    }

    case ON_BACKTRACK(PATH_BEGIN):
    case ON_BACKTRACK(PATH_END): {
      jv_free(jq->path);
      jq->path = stack_pop(jq);
      goto do_backtrack;
    }

    case INDEX: {
      jv t = stack_pop(jq);
      jv k = stack_pop(jq);
      path_append(jq, jv_copy(k));
      jv v = jv_get(t, k);
      if (jv_is_valid(v)) {
        stack_push(jq, v);
      } else {
        print_error(v);
        goto do_backtrack;
      }
      break;
    }


    case JUMP: {
      uint16_t offset = *pc++;
      pc += offset;
      break;
    }

    case JUMP_F: {
      uint16_t offset = *pc++;
      jv t = stack_pop(jq);
      jv_kind kind = jv_get_kind(t);
      if (kind == JV_KIND_FALSE || kind == JV_KIND_NULL) {
        pc += offset;
      }
      stack_push(jq, t); // FIXME do this better
      break;
    }

    case EACH: 
      stack_push(jq, jv_number(-1));
      // fallthrough
    case ON_BACKTRACK(EACH): {
      int idx = jv_number_value(stack_pop(jq));
      jv container = stack_pop(jq);

      int keep_going;
      jv key, value;
      if (jv_get_kind(container) == JV_KIND_ARRAY) {
        if (opcode == EACH) idx = 0;
        else idx = idx + 1;
        keep_going = idx < jv_array_length(jv_copy(container));
        if (keep_going) {
          key = jv_number(idx);
          value = jv_array_get(jv_copy(container), idx);
        }
      } else if (jv_get_kind(container) == JV_KIND_OBJECT) {
        if (opcode == EACH) idx = jv_object_iter(container);
        else idx = jv_object_iter_next(container, idx);
        keep_going = jv_object_iter_valid(container, idx);
        if (keep_going) {
          key = jv_object_iter_key(container, idx);
          value = jv_object_iter_value(container, idx);
        }
      } else {
        assert(opcode == EACH);
        print_error(jv_invalid_with_msg(jv_string_fmt("Cannot iterate over %s",
                                                      jv_kind_name(jv_get_kind(container)))));
        keep_going = 0;
      }

      if (!keep_going) {
        jv_free(container);
        goto do_backtrack;
      } else {
        stack_save(jq, pc - 1);
        stack_push(jq, container);
        stack_push(jq, jv_number(idx));
        stack_switch(jq);
        path_append(jq, key);
        stack_push(jq, value);
      }
      break;
    }

    do_backtrack:
    case BACKTRACK: {
      pc = stack_restore(jq);
      if (!pc) {
        return jv_invalid();
      }
      backtracking = 1;
      break;
    }

    case FORK: {
      stack_save(jq, pc - 1);
      stack_switch(jq);
      pc++; // skip offset this time
      break;
    }

    case ON_BACKTRACK(FORK): {
      uint16_t offset = *pc++;
      pc += offset;
      break;
    }
      
    case CALL_BUILTIN: {
      int nargs = *pc++;
      jv top = stack_pop(jq);
      cfunc_input[0] = top;
      for (int i = 1; i < nargs; i++) {
        cfunc_input[i] = stack_pop(jq);
      }
      struct cfunction* func = &frame_current_bytecode(&jq->frame_stk)->globals->cfunctions[*pc++];
      top = cfunction_invoke(func, cfunc_input);
      if (jv_is_valid(top)) {
        stack_push(jq, top);
      } else {
        print_error(top);
        goto do_backtrack;
      }
      break;
    }

    case CALL_JQ: {
      uint16_t nclosures = *pc++;
      uint16_t* retaddr = pc + 2 + nclosures*2;
      frame_ptr new_frame = frame_push(&jq->frame_stk, 
                                       make_closure(&jq->frame_stk, frame_current(&jq->frame_stk), pc),
                                       retaddr);
      pc += 2;
      frame_ptr old_frame = forkable_stack_peek_next(&jq->frame_stk, new_frame);
      assert(nclosures == frame_self(new_frame)->bc->nclosures);
      for (int i=0; i<nclosures; i++) {
        *frame_closure_arg(new_frame, i) = make_closure(&jq->frame_stk, old_frame, pc);
        pc += 2;
      }

      pc = frame_current_bytecode(&jq->frame_stk)->code;
      break;
    }

    case RET: {
      uint16_t* retaddr = *frame_current_retaddr(&jq->frame_stk);
      if (retaddr) {
        // function return
        pc = retaddr;
        frame_pop(&jq->frame_stk);
      } else {
        // top-level return, yielding value
        jv value = stack_pop(jq);
        stack_save(jq, pc - 1);
        stack_push(jq, jv_null());
        stack_switch(jq);
        return value;
      }
      break;
    }
    case ON_BACKTRACK(RET): {
      // resumed after top-level return
      goto do_backtrack;
    }
    }
  }
}