builtin.c

#include <assert.h>
#include <limits.h>
#include <math.h>
#include <oniguruma.h>
#include <stdlib.h>
#include <string.h>
#include "builtin.h"
#include "compile.h"
#include "jq_parser.h"
#include "bytecode.h"
#include "locfile.h"
#include "jv_unicode.h"


static jv type_error(jv bad, const char* msg) {
  jv err = jv_invalid_with_msg(jv_string_fmt("%s %s",
                                             jv_kind_name(jv_get_kind(bad)),
                                             msg));
  jv_free(bad);
  return err;
}

static jv type_error2(jv bad1, jv bad2, const char* msg) {
  jv err = jv_invalid_with_msg(jv_string_fmt("%s and %s %s",
                                             jv_kind_name(jv_get_kind(bad1)),
                                             jv_kind_name(jv_get_kind(bad2)),
                                             msg));
  jv_free(bad1);
  jv_free(bad2);
  return err;
}

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");
  }
}

#define LIBM_DD(name) \
static jv f_ ## name(jv input) { \
  if (jv_get_kind(input) != JV_KIND_NUMBER) { \
    return type_error(input, "number required"); \
  } \
  jv ret = jv_number(name(jv_number_value(input))); \
  jv_free(input); \
  return ret; \
}
#include "libm.h"
#undef LIBM_DD

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;
}

static jv f_startswith(jv a, jv b) {
  int alen = jv_string_length_bytes(jv_copy(a));
  int blen = jv_string_length_bytes(jv_copy(b));
  jv ret;

  if (blen <= alen && memcmp(jv_string_value(a), jv_string_value(b), blen) == 0)
    ret = jv_true();
  else
    ret = jv_false();
  jv_free(a);
  jv_free(b);
  return ret;
}

static jv f_endswith(jv a, jv b) {
  const char *astr = jv_string_value(a);
  const char *bstr = jv_string_value(b);
  size_t alen = jv_string_length_bytes(jv_copy(a));
  size_t blen = jv_string_length_bytes(jv_copy(b));
  jv ret;;

  if (alen < blen ||
     memcmp(astr + (alen - blen), bstr, blen) != 0)
    ret = jv_false();
  else
    ret = jv_true();
  jv_free(a);
  jv_free(b);
  return ret;
}

static jv f_ltrimstr(jv input, jv left) {
  if (jv_get_kind(f_startswith(jv_copy(input), jv_copy(left))) != JV_KIND_TRUE) {
    jv_free(left);
    return input;
  }
  /*
   * FIXME It'd be better to share the suffix with the original input --
   * that we could do, we just can't share prefixes.
   */
  int prefixlen = jv_string_length_bytes(left);
  jv res = jv_string_sized(jv_string_value(input) + prefixlen,
                           jv_string_length_bytes(jv_copy(input)) - prefixlen);
  jv_free(input);
  return res;
}

static jv f_rtrimstr(jv input, jv right) {
  if (jv_get_kind(f_endswith(jv_copy(input), jv_copy(right))) == JV_KIND_TRUE) {
    jv res = jv_string_sized(jv_string_value(input),
                             jv_string_length_bytes(jv_copy(input)) - jv_string_length_bytes(right));
    jv_free(input);
    return res;
  }
  jv_free(right);
  return input;
}

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);
    }
    jv_free(a);
    jv_free(b);
    return out;
  } else {
    return type_error2(a, b, "cannot be subtracted");
  }
}

static jv f_multiply(jv input, jv a, jv b) {
  jv_kind ak = jv_get_kind(a);
  jv_kind bk = jv_get_kind(b);
  jv_free(input);
  if (ak == JV_KIND_NUMBER && bk == JV_KIND_NUMBER) {
    return jv_number(jv_number_value(a) * jv_number_value(b));
  } else if ((ak == JV_KIND_STRING && bk == JV_KIND_NUMBER) ||
             (ak == JV_KIND_NUMBER && bk == JV_KIND_STRING)) {
    jv str = a;
    jv num = b;
    if (ak == JV_KIND_NUMBER) {
      str = b;
      num = a;
    }
    int n;
    size_t alen = jv_string_length_bytes(jv_copy(str));
    jv res = str;

    for (n = jv_number_value(num) - 1; n > 0; n--)
      res = jv_string_append_buf(res, jv_string_value(str), alen);

    jv_free(num);
    if (n < 0) {
      jv_free(str);
      return jv_null();
    }
    return res;
  } else if (ak == JV_KIND_OBJECT && bk == JV_KIND_OBJECT) {
    return jv_object_merge_recursive(a, b);
  } else {
    return type_error2(a, b, "cannot be multiplied");
  }  
}

static jv f_divide(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_STRING && jv_get_kind(b) == JV_KIND_STRING) {
    return jv_string_split(a, b);
  } else {
    return type_error2(a, b, "cannot be divided");
  }  
}

static jv f_mod(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((intmax_t)jv_number_value(a) % (intmax_t)jv_number_value(b));
  } else {
    return type_error2(a, b, "cannot be divided");
  }  
}

static jv f_equal(jv input, jv a, jv b) {
  jv_free(input);
  return jv_bool(jv_equal(a, b));
}

static jv f_notequal(jv input, jv a, jv b) {
  jv_free(input);
  return jv_bool(!jv_equal(a, b));
}

enum cmp_op {
  CMP_OP_LESS,
  CMP_OP_GREATER,
  CMP_OP_LESSEQ,
  CMP_OP_GREATEREQ
};

static jv order_cmp(jv input, jv a, jv b, enum cmp_op op) {
  jv_free(input);
  int r = jv_cmp(a, b);
  return jv_bool((op == CMP_OP_LESS && r < 0) ||
                 (op == CMP_OP_LESSEQ && r <= 0) ||
                 (op == CMP_OP_GREATEREQ && r >= 0) ||
                 (op == CMP_OP_GREATER && r > 0));
}

static jv f_less(jv input, jv a, jv b) {
  return order_cmp(input, a, b, CMP_OP_LESS);
}

static jv f_greater(jv input, jv a, jv b) {
  return order_cmp(input, a, b, CMP_OP_GREATER);
}

static jv f_lesseq(jv input, jv a, jv b) {
  return order_cmp(input, a, b, CMP_OP_LESSEQ);
}

static jv f_greatereq(jv input, jv a, jv b) {
  return order_cmp(input, a, b, CMP_OP_GREATEREQ);
}

static jv f_contains(jv a, jv b) {
  if (jv_get_kind(a) == jv_get_kind(b)) {
    return jv_bool(jv_contains(a, b));
  } else {
    return type_error2(a, b, "cannot have their containment checked");
  }
}

static jv f_dump(jv input) {
  return jv_dump_string(input, 0);
}

static jv f_json_parse(jv input) {
  if (jv_get_kind(input) != JV_KIND_STRING)
    return type_error(input, "only strings can be parsed");
  jv res = jv_parse_sized(jv_string_value(input),
                          jv_string_length_bytes(jv_copy(input)));
  jv_free(input);
  return res;
}

static jv f_tonumber(jv input) {
  if (jv_get_kind(input) == JV_KIND_NUMBER) {
    return input;
  }
  if (jv_get_kind(input) == JV_KIND_STRING) {
    jv parsed = jv_parse(jv_string_value(input));
    if (!jv_is_valid(parsed) || jv_get_kind(parsed) == JV_KIND_NUMBER) {
      jv_free(input);
      return parsed;
    }
  }
  return type_error(input, "cannot be parsed as a number");
}

static jv f_length(jv input) {
  if (jv_get_kind(input) == JV_KIND_ARRAY) {
    return jv_number(jv_array_length(input));
  } else if (jv_get_kind(input) == JV_KIND_OBJECT) {
    return jv_number(jv_object_length(input));
  } else if (jv_get_kind(input) == JV_KIND_STRING) {
    return jv_number(jv_string_length_codepoints(input));
  } else if (jv_get_kind(input) == JV_KIND_NUMBER) {
    return jv_number(fabs(jv_number_value(input)));
  } else if (jv_get_kind(input) == JV_KIND_NULL) {
    jv_free(input);
    return jv_number(0);
  } else {
    return type_error(input, "has no length");
  }
}

static jv f_tostring(jv input) {
  if (jv_get_kind(input) == JV_KIND_STRING) {
    return input;
  } else {
    return jv_dump_string(input, 0);
  }
}

#define CHARS_ALPHANUM "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"

static jv escape_string(jv input, const char* escapings) {

  assert(jv_get_kind(input) == JV_KIND_STRING);
  const char* lookup[128] = {0};
  const char* p = escapings;
  while (*p) {
    lookup[(int)*p] = p+1;
    p++;
    p += strlen(p);
    p++;
  }

  jv ret = jv_string("");
  const char* i = jv_string_value(input);
  const char* end = i + jv_string_length_bytes(jv_copy(input));
  const char* cstart;
  int c = 0;
  while ((i = jvp_utf8_next((cstart = i), end, &c))) {
    assert(c != -1);
    if (c < 128 && lookup[c]) {
      ret = jv_string_append_str(ret, lookup[c]);
    } else {
      ret = jv_string_append_buf(ret, cstart, i - cstart);
    }
  }
  jv_free(input);
  return ret;

}

static jv f_format(jv input, jv fmt) {
  if (jv_get_kind(fmt) != JV_KIND_STRING) {
    jv_free(input);
    return type_error(fmt, "is not a valid format");
  }
  const char* fmt_s = jv_string_value(fmt);
  if (!strcmp(fmt_s, "json")) {
    jv_free(fmt);
    return jv_dump_string(input, 0);
  } else if (!strcmp(fmt_s, "text")) {
    jv_free(fmt);
    return f_tostring(input);
  } else if (!strcmp(fmt_s, "csv")) {
    jv_free(fmt);
    if (jv_get_kind(input) != JV_KIND_ARRAY)
      return type_error(input, "cannot be csv-formatted, only array");
    jv line = jv_string("");
    jv_array_foreach(input, i, x) {
      if (i) line = jv_string_append_str(line, ",");
      switch (jv_get_kind(x)) {
      case JV_KIND_NULL:
        /* null rendered as empty string */
        jv_free(x);
        break;
      case JV_KIND_TRUE:
      case JV_KIND_FALSE:
        line = jv_string_concat(line, jv_dump_string(x, 0));
        break;
      case JV_KIND_NUMBER:
        if (jv_number_value(x) != jv_number_value(x)) {
          /* NaN, render as empty string */
          jv_free(x);
        } else {
          line = jv_string_concat(line, jv_dump_string(x, 0));
        }
        break;
      case JV_KIND_STRING: {
        line = jv_string_append_str(line, "\"");
        line = jv_string_concat(line, escape_string(x, "\"\"\"\0"));
        line = jv_string_append_str(line, "\"");
        break;
      }
      default:
        jv_free(input);
        jv_free(line);
        return type_error(x, "is not valid in a csv row");
      }
    }
    jv_free(input);
    return line;
  } else if (!strcmp(fmt_s, "html")) {
    jv_free(fmt);
    return escape_string(f_tostring(input), "&&amp;\0<&lt;\0>&gt;\0'&apos;\0\"&quot;\0");
  } else if (!strcmp(fmt_s, "uri")) {
    jv_free(fmt);
    input = f_tostring(input);

    int unreserved[128] = {0};
    const char* p = CHARS_ALPHANUM "-_.!~*'()";
    while (*p) unreserved[(int)*p++] = 1;

    jv line = jv_string("");
    const char* s = jv_string_value(input);
    for (int i=0; i<jv_string_length_bytes(jv_copy(input)); i++) {
      unsigned ch = (unsigned)(unsigned char)*s;
      if (ch < 128 && unreserved[ch]) {
        line = jv_string_append_buf(line, s, 1);
      } else {
        line = jv_string_concat(line, jv_string_fmt("%%%02x", ch));
      }
      s++;
    }
    jv_free(input);
    return line;
  } else if (!strcmp(fmt_s, "sh")) {
    jv_free(fmt);
    if (jv_get_kind(input) != JV_KIND_ARRAY)
      input = jv_array_set(jv_array(), 0, input);
    jv line = jv_string("");
    jv_array_foreach(input, i, x) {
      if (i) line = jv_string_append_str(line, " ");
      switch (jv_get_kind(x)) {
      case JV_KIND_NULL:
      case JV_KIND_TRUE:
      case JV_KIND_FALSE:
      case JV_KIND_NUMBER:
        line = jv_string_concat(line, jv_dump_string(x, 0));
        break;

      case JV_KIND_STRING: {
        line = jv_string_append_str(line, "'");
        line = jv_string_concat(line, escape_string(x, "''\\''\0"));
        line = jv_string_append_str(line, "'");
        break;
      }

      default:
        jv_free(input);
        jv_free(line);
        return type_error(x, "can not be escaped for shell");
      }
    }
    jv_free(input);
    return line;
  } else if (!strcmp(fmt_s, "base64")) {
    jv_free(fmt);
    input = f_tostring(input);
    jv line = jv_string("");
    const char b64[64 + 1] = CHARS_ALPHANUM "+/";
    const char* data = jv_string_value(input);
    int len = jv_string_length_bytes(jv_copy(input));
    for (int i=0; i<len; i+=3) {
      uint32_t code = 0;
      int n = len - i >= 3 ? 3 : len-i;
      for (int j=0; j<3; j++) {
        code <<= 8;
        code |= j < n ? (unsigned)data[i+j] : 0;
      }
      char buf[4];
      for (int j=0; j<4; j++) {
        buf[j] = b64[(code >> (18 - j*6)) & 0x3f];
      }
      if (n < 3) buf[3] = '=';
      if (n < 2) buf[2] = '=';
      line = jv_string_append_buf(line, buf, sizeof(buf));
    }
    jv_free(input);
    return line;
  } else {
    jv_free(input);
    return jv_invalid_with_msg(jv_string_concat(fmt, jv_string(" is not a valid format")));
  }
}

static jv f_keys(jv input) {
  if (jv_get_kind(input) == JV_KIND_OBJECT || jv_get_kind(input) == JV_KIND_ARRAY) {
    return jv_keys(input);
  } else {
    return type_error(input, "has no keys");
  }
}

static jv f_sort(jv input){
  if (jv_get_kind(input) == JV_KIND_ARRAY) {
    return jv_sort(input, jv_copy(input));
  } else {
    return type_error(input, "cannot be sorted, as it is not an array");
  }
}

static jv f_sort_by_impl(jv input, jv keys) {
  if (jv_get_kind(input) == JV_KIND_ARRAY && 
      jv_get_kind(keys) == JV_KIND_ARRAY &&
      jv_array_length(jv_copy(input)) == jv_array_length(jv_copy(keys))) {
    return jv_sort(input, keys);
  } else {
    return type_error2(input, keys, "cannot be sorted, as they are not both arrays");
  }
}

static jv f_group_by_impl(jv input, jv keys) {
  if (jv_get_kind(input) == JV_KIND_ARRAY && 
      jv_get_kind(keys) == JV_KIND_ARRAY &&
      jv_array_length(jv_copy(input)) == jv_array_length(jv_copy(keys))) {
    return jv_group(input, keys);
  } else {
    return type_error2(input, keys, "cannot be sorted, as they are not both arrays");
  }
}

static int f_match_name_iter(const UChar* name, const UChar *name_end, int ngroups,
    int *groups, regex_t *reg, void *arg) {
  jv captures = *(jv*)arg;
  for (int i = 0; i < ngroups; ++i) {
    jv cap = jv_array_get(jv_copy(captures),groups[i]-1);
    if (jv_get_kind(cap) == JV_KIND_OBJECT) {
      cap = jv_object_set(cap, jv_string("name"), jv_string_sized((const char*)name, name_end-name));
      captures = jv_array_set(captures,groups[i]-1,cap);
    } else {
      jv_free(cap);
    }
  }
  *(jv *)arg = captures;
  return 0;
}


static jv f_match(jv input, jv regex, jv modifiers, jv testmode) {
  int test = jv_equal(testmode, jv_true());
  jv result;
  int onigret;
  int global = 0;
  regex_t *reg;
  OnigErrorInfo einfo;
  OnigRegion* region;

  if (jv_get_kind(input) != JV_KIND_STRING) {
    jv_free(regex);
    jv_free(modifiers);
    return type_error(input, "cannot be matched, as it is not a string");
  }

  if (jv_get_kind(regex) != JV_KIND_STRING) {
    jv_free(input);
    jv_free(modifiers);
    return type_error(regex, "is not a string");
  }

  OnigOptionType options = ONIG_OPTION_CAPTURE_GROUP;

  if (jv_get_kind(modifiers) == JV_KIND_STRING) {
    jv modarray = jv_string_explode(jv_copy(modifiers));
    jv_array_foreach(modarray, i, mod) {
      switch ((int)jv_number_value(mod)) {
        case 'g':
          global = 1;
          break;
        case 'i':
          options |= ONIG_OPTION_IGNORECASE;
          break;
        case 'x':
          options |= ONIG_OPTION_EXTEND;
          break;
        case 'm':
          options |= ONIG_OPTION_MULTILINE;
          break;
        case 's':
          options |= ONIG_OPTION_SINGLELINE;
          break;
        case 'p':
          options |= ONIG_OPTION_MULTILINE | ONIG_OPTION_SINGLELINE;
          break;
        case 'l':
          options |= ONIG_OPTION_FIND_LONGEST;
          break;
        case 'n':
          options |= ONIG_OPTION_FIND_NOT_EMPTY;
          break;
        default:
          jv_free(input);
          jv_free(regex);
          jv_free(modarray);
          return jv_invalid_with_msg(jv_string_concat(modifiers,
                jv_string(" is not a valid modifier string")));
      }
    }
    jv_free(modarray);
  } else if (jv_get_kind(modifiers) != JV_KIND_NULL) { 
    // If it isn't a string or null, then it is the wrong type...
    jv_free(input);
    jv_free(regex);
    return type_error(modifiers, "is not a string");
  }

  jv_free(modifiers);

  onigret = onig_new(&reg, (const UChar*)jv_string_value(regex),
      (const UChar*)(jv_string_value(regex) + jv_string_length_bytes(jv_copy(regex))),
      options, ONIG_ENCODING_UTF8, ONIG_SYNTAX_PERL_NG, &einfo);
  if (onigret != ONIG_NORMAL) {
    UChar ebuf[ONIG_MAX_ERROR_MESSAGE_LEN];
    onig_error_code_to_str(ebuf, onigret, einfo);
    jv_free(input);
    jv_free(regex);
    return jv_invalid_with_msg(jv_string_concat(jv_string("Regex failure: "),
          jv_string((char*)ebuf)));
  }
  if (!test)
    result = jv_array();
  const char *input_string = jv_string_value(input);
  const UChar* start = (const UChar*)jv_string_value(input);
  const unsigned long length = jv_string_length_bytes(jv_copy(input));
  const UChar* end = start + length;
  region = onig_region_new();
  do {
    onigret = onig_search(reg, 
        (const UChar*)jv_string_value(input), end, /* string boundaries */
        start, end, /* search boundaries */
        region, ONIG_OPTION_NONE);
    if (onigret >= 0) {
      if (test) {
        result = jv_true();
        break;
      }

      // Zero-width match
      if (region->end[0] == region->beg[0]) {
        unsigned long idx;
        const char *fr = (const char*)input_string;
        for (idx = 0; fr != input_string+region->beg[0]; idx++) {
          fr += jvp_utf8_decode_length(*fr);
        }
        jv match = jv_object_set(jv_object(), jv_string("offset"), jv_number(idx));
        match = jv_object_set(match, jv_string("length"), jv_number(0));
        match = jv_object_set(match, jv_string("string"), jv_string(""));
        match = jv_object_set(match, jv_string("captures"), jv_array());
        result = jv_array_append(result, match);
        start += 1;
        continue;
      }

      unsigned long idx;
      unsigned long len;
      const char *fr = (const char*)input_string;

      for (idx = len = 0; fr != input_string+region->end[0]; len++) {
        if (fr == input_string+region->beg[0]) idx = len, len=0;
        fr += jvp_utf8_decode_length(*fr);
      }

      jv match = jv_object_set(jv_object(), jv_string("offset"), jv_number(idx));

      unsigned long blen = region->end[0]-region->beg[0];
      match = jv_object_set(match, jv_string("length"), jv_number(len));
      match = jv_object_set(match, jv_string("string"), jv_string_sized(input_string+region->beg[0],blen));
      jv captures = jv_array();
      for (int i = 1; i < region->num_regs; ++i) {
        // Empty capture.
        if (region->beg[i] == region->end[i]) {
          // Didn't match.
          jv cap;
          if (region->beg[i] == -1) {
            cap = jv_object_set(jv_object(), jv_string("offset"), jv_number(-1));
            cap = jv_object_set(cap, jv_string("string"), jv_null());
          } else {
            fr = input_string;
            for (idx = 0; fr != input_string+region->beg[i]; idx++) {
              fr += jvp_utf8_decode_length(*fr);
            }
            cap = jv_object_set(jv_object(), jv_string("offset"), jv_number(idx));
            cap = jv_object_set(cap, jv_string("string"), jv_string(""));
          }
          cap = jv_object_set(cap, jv_string("length"), jv_number(0));
          cap = jv_object_set(cap, jv_string("name"), jv_null());
          captures = jv_array_append(captures, cap);
          continue;
        }
        fr = input_string;
        for (idx = len = 0; fr != input_string+region->end[i]; len++) {
          if (fr == input_string+region->beg[i]) idx = len, len=0;
          fr += jvp_utf8_decode_length(*fr);
        }

        blen = region->end[i]-region->beg[i];
        jv cap = jv_object_set(jv_object(), jv_string("offset"), jv_number(idx));
        cap = jv_object_set(cap, jv_string("length"), jv_number(len));
        cap = jv_object_set(cap, jv_string("string"), jv_string_sized(input_string+region->beg[i],blen));
        cap = jv_object_set(cap, jv_string("name"), jv_null());
        captures = jv_array_append(captures,cap);
      }
      onig_foreach_name(reg,f_match_name_iter,&captures);
      match = jv_object_set(match, jv_string("captures"), captures);
      result = jv_array_append(result, match);
      start = (const UChar*)(input_string+region->end[0]);
      onig_region_free(region,0);
    } else if (onigret == ONIG_MISMATCH) {
      if (test)
        result = jv_false();
      break;
    } else { /* Error */
      UChar ebuf[ONIG_MAX_ERROR_MESSAGE_LEN];
      onig_error_code_to_str(ebuf, onigret, einfo);
      jv_free(result);
      result = jv_invalid_with_msg(jv_string_concat(jv_string("Regex failure: "),
            jv_string((char*)ebuf)));
      break;
    }
  } while (global && start != end);
  onig_region_free(region,1);
  region = NULL;
  if (region)
    onig_region_free(region,1);
  onig_free(reg);
  jv_free(input);
  jv_free(regex);
  return result;
}

static jv minmax_by(jv values, jv keys, int is_min) {
  if (jv_get_kind(values) != JV_KIND_ARRAY)
    return type_error2(values, keys, "cannot be iterated over");
  if (jv_get_kind(keys) != JV_KIND_ARRAY)
    return type_error2(values, keys, "cannot be iterated over");
  if (jv_array_length(jv_copy(values)) != jv_array_length(jv_copy(keys)))
    return type_error2(values, keys, "have wrong length");

  if (jv_array_length(jv_copy(values)) == 0) {
    jv_free(values);
    jv_free(keys);
    return jv_null();
  }
  jv ret = jv_array_get(jv_copy(values), 0);
  jv retkey = jv_array_get(jv_copy(keys), 0);
  for (int i=1; i<jv_array_length(jv_copy(values)); i++) {
    jv item = jv_array_get(jv_copy(keys), i);
    int cmp = jv_cmp(jv_copy(item), jv_copy(retkey));
    if ((cmp < 0) == (is_min == 1)) {
      jv_free(retkey);
      retkey = item;
      jv_free(ret);
      ret = jv_array_get(jv_copy(values), i);
    } else {
      jv_free(item);
    }
  }
  jv_free(values);
  jv_free(keys);
  jv_free(retkey);
  return ret;
}

static jv f_min(jv x) {
  return minmax_by(x, jv_copy(x), 1);
}

static jv f_max(jv x) {
  return minmax_by(x, jv_copy(x), 0);
}

static jv f_min_by_impl(jv x, jv y) {
  return minmax_by(x, y, 1);
}

static jv f_max_by_impl(jv x, jv y) {
  return minmax_by(x, y, 0);
}


static jv f_type(jv input) {
  jv out = jv_string(jv_kind_name(jv_get_kind(input)));
  jv_free(input);
  return out;
}

static jv f_error(jv input, jv msg) {
  jv_free(input);
  msg = f_tostring(msg);
  return jv_invalid_with_msg(msg);
}

// FIXME Should autoconf check for this!
#ifndef WIN32
extern const char **environ;
#endif

static jv f_env(jv input) {
  jv_free(input);
  jv env = jv_object();
  const char *var, *val;
  for (const char **e = environ; *e != NULL; e++) {
    var = e[0];
    val = strchr(e[0], '=');
    if (val == NULL)
      env = jv_object_set(env, jv_string(var), jv_null());
    else if (var - val < INT_MAX)
      env = jv_object_set(env, jv_string_sized(var, val - var), jv_string(val + 1));
  }
  return env;
}

#define LIBM_DD(name) \
  {(cfunction_ptr)f_ ## name, "_" #name, 1},
   
static const struct cfunction function_list[] = {
#include "libm.h"
  {(cfunction_ptr)f_plus, "_plus", 3},
  {(cfunction_ptr)f_negate, "_negate", 1},
  {(cfunction_ptr)f_minus, "_minus", 3},
  {(cfunction_ptr)f_multiply, "_multiply", 3},
  {(cfunction_ptr)f_divide, "_divide", 3},
  {(cfunction_ptr)f_mod, "_mod", 3},
  {(cfunction_ptr)f_dump, "tojson", 1},
  {(cfunction_ptr)f_json_parse, "fromjson", 1},
  {(cfunction_ptr)f_tonumber, "tonumber", 1},
  {(cfunction_ptr)f_tostring, "tostring", 1},
  {(cfunction_ptr)f_keys, "keys", 1},
  {(cfunction_ptr)f_startswith, "startswith", 2},
  {(cfunction_ptr)f_endswith, "endswith", 2},
  {(cfunction_ptr)f_ltrimstr, "ltrimstr", 2},
  {(cfunction_ptr)f_rtrimstr, "rtrimstr", 2},
  {(cfunction_ptr)jv_string_split, "split", 2},
  {(cfunction_ptr)jv_string_explode, "explode", 1},
  {(cfunction_ptr)jv_string_implode, "implode", 1},
  {(cfunction_ptr)jv_setpath, "setpath", 3}, // FIXME typechecking
  {(cfunction_ptr)jv_getpath, "getpath", 2},
  {(cfunction_ptr)jv_delpaths, "delpaths", 2},
  {(cfunction_ptr)jv_has, "has", 2},
  {(cfunction_ptr)f_equal, "_equal", 3},
  {(cfunction_ptr)f_notequal, "_notequal", 3},
  {(cfunction_ptr)f_less, "_less", 3},
  {(cfunction_ptr)f_greater, "_greater", 3},
  {(cfunction_ptr)f_lesseq, "_lesseq", 3},
  {(cfunction_ptr)f_greatereq, "_greatereq", 3},
  {(cfunction_ptr)f_contains, "contains", 2},
  {(cfunction_ptr)f_length, "length", 1},
  {(cfunction_ptr)f_type, "type", 1},
  {(cfunction_ptr)f_sort, "sort", 1},
  {(cfunction_ptr)f_sort_by_impl, "_sort_by_impl", 2},
  {(cfunction_ptr)f_group_by_impl, "_group_by_impl", 2},
  {(cfunction_ptr)f_min, "min", 1},
  {(cfunction_ptr)f_max, "max", 1},
  {(cfunction_ptr)f_min_by_impl, "_min_by_impl", 2},
  {(cfunction_ptr)f_max_by_impl, "_max_by_impl", 2},
  {(cfunction_ptr)f_error, "error", 2},
  {(cfunction_ptr)f_format, "format", 2},
  {(cfunction_ptr)f_env, "env", 1},
  {(cfunction_ptr)f_match, "_match_impl", 4},
};
#undef LIBM_DD

struct bytecoded_builtin { const char* name; block code; };
static block bind_bytecoded_builtins(block b) {
  block builtins = gen_noop();
  {
    struct bytecoded_builtin builtin_defs[] = {
      {"empty", gen_op_simple(BACKTRACK)},
      {"false", gen_const(jv_false())},
      {"true", gen_const(jv_true())},
      {"null", gen_const(jv_null())},
      {"not", gen_condbranch(gen_const(jv_false()),
                             gen_const(jv_true()))}
    };
    for (unsigned i=0; i<sizeof(builtin_defs)/sizeof(builtin_defs[0]); i++) {
      builtins = BLOCK(builtins, gen_function(builtin_defs[i].name, gen_noop(),
                                              builtin_defs[i].code));
    }
  }
  {
    struct bytecoded_builtin builtin_def_1arg[] = {
      {"path", BLOCK(gen_op_simple(PATH_BEGIN), 
                     gen_call("arg", gen_noop()),
                     gen_op_simple(PATH_END))},
    };
    for (unsigned i=0; i<sizeof(builtin_def_1arg)/sizeof(builtin_def_1arg[0]); i++) {
      builtins = BLOCK(builtins, gen_function(builtin_def_1arg[i].name,
                                              gen_param("arg"),
                                              builtin_def_1arg[i].code));
    }
  }
  {
    block rangevar = gen_op_var_fresh(STOREV, "rangevar");
    block init = BLOCK(gen_op_simple(DUP), gen_call("start", gen_noop()), rangevar);
    block range = BLOCK(init, 
                        gen_call("end", gen_noop()),
                        gen_op_bound(RANGE, rangevar));
    builtins = BLOCK(builtins, gen_function("range",
                                            BLOCK(gen_param("start"), gen_param("end")),
                                            range));
  }
  
  return block_bind_referenced(builtins, b, OP_IS_CALL_PSEUDO);
}

#define LIBM_DD(name) "def " #name ": _" #name ";",

static const char* const jq_builtins[] = {
  "def map(f): [.[] | f];",
  "def select(f): if f then . else empty end;",
  "def sort(f): _sort_by_impl(map([f]));",
  "def sort_by(f): sort(f);",
  "def group(f): _group_by_impl(map([f]));",
  "def group_by(f): group(f);",
  "def unique: group(.) | map(.[0]);",
  "def unique(f): group(f) | map(.[0]);",
  "def unique_by(f): unique(f);",
  "def max(f): _max_by_impl(map([f]));",
  "def min(f): _min_by_impl(map([f]));",
  "def max_by(f): max(f);",
  "def min_by(f): min(f);",
#include "libm.h"
  "def add: reduce .[] as $x (null; . + $x);",
  "def del(f): delpaths([path(f)]);",
  "def _assign(paths; value): value as $v | reduce path(paths) as $p (.; setpath($p; $v));",
  "def _modify(paths; update): reduce path(paths) as $p (.; setpath($p; getpath($p) | update));",
  "def recurse(f): ., (f | select(. != null) | recurse(f));",
  "def recurse: recurse(.[]?);",
  "def recurse_down: recurse;",
  "def to_entries: [keys[] as $k | {key: $k, value: .[$k]}];",
  "def from_entries: map({(.key): .value}) | add | .//={};",
  "def with_entries(f): to_entries | map(f) | from_entries;",
  "def reverse: [.[length - 1 - range(0;length)]];",
  "def indices(i): if type == \"array\" and (i|type) == \"array\" then .[i] elif type == \"array\" then .[[i]] else .[i] end;",
  "def index(i):   if type == \"array\" and (i|type) == \"array\" then .[i] elif type == \"array\" then .[[i]] else .[i] end | .[0];",
  "def rindex(i):  if type == \"array\" and (i|type) == \"array\" then .[i] elif type == \"array\" then .[[i]] else .[i] end | .[-1:][0];",
  "def paths: path(recurse(if (type|. == \"array\" or . == \"object\") then .[] else empty end))|select(length > 0);",
  "def paths(node_filter): . as $dot|paths|select(. as $p|$dot|getpath($p)|node_filter);",
  "def any: reduce .[] as $i (false; . or $i);",
  "def all: reduce .[] as $i (true; . and $i);",
  "def arrays: select(type == \"array\");",
  "def objects: select(type == \"object\");",
  "def iterables: arrays, objects;",
  "def booleans: select(type == \"boolean\");",
  "def numbers: select(type == \"number\");",
  "def strings: select(type == \"string\");",
  "def nulls: select(type == \"null\");",
  "def values: arrays, objects, booleans, numbers, strings;",
  "def scalars: select(. == null or . == true or . == false or type == \"number\" or type == \"string\");",
  "def leaf_paths: paths(scalars);",
  "def join(x): reduce .[] as $i (\"\"; . + (if . == \"\" then $i else x + $i end));",
  "def flatten: reduce .[] as $i ([]; if $i | type == \"array\" then . + ($i | flatten) else . + [$i] end);",
  "def flatten(x): reduce .[] as $i ([]; if $i | type == \"array\" and x > 0 then . + ($i | flatten(x-1)) else . + [$i] end);",
  "def range(x): range(0;x);",
  "def match(re; mode): _match_impl(re; mode; false)|.[];",
  "def match(val): if val | type == \"string\" then match(val; null) elif val | type == \"array\" and (val | length) > 1 then match(val[0]; val[1]) elif val | type == \"array\" and (val | length > 0) then match(val[0]; null) else error((val | type) + \" not a string or array\") end;",
  "def test(re; mode): _match_impl(re; mode; true);",
  "def test(val): if val |type == \"string\" then test(val; null) elif val | type == \"array\" and (val | length) > 1 then test(val[0]; val[1]) elif val | type == \"array\" and (val | length > 0) then test(val[0]; null) else error((val | type) + \" not a string or array\") end;",
//  "def test(re): _match(re; null; 1);",
  
};
#undef LIBM_DD


static int builtins_bind_one(jq_state *jq, block* bb, const char* code) {
  struct locfile src;
  locfile_init(&src, jq, code, strlen(code));
  block funcs;
  int nerrors = jq_parse_library(&src, &funcs);
  if (nerrors == 0) {
    *bb = block_bind_referenced(funcs, *bb, OP_IS_CALL_PSEUDO);
  }
  locfile_free(&src);
  return nerrors;
}

static int slurp_lib(jq_state *jq, block* bb) {
  int nerrors = 0;
  char* home = getenv("HOME");
  if (home) {    // silently ignore no $HOME
    jv filename = jv_string_append_str(jv_string(home), "/.jq");
    jv data = jv_load_file(jv_string_value(filename), 1);
    if (jv_is_valid(data)) {
      nerrors = builtins_bind_one(jq, bb, jv_string_value(data) );
    }
    jv_free(filename);
    jv_free(data);
  }
  return nerrors;
}

int builtins_bind(jq_state *jq, block* bb) {
  int nerrors = slurp_lib(jq, bb);
  if (nerrors) {
    block_free(*bb);
    return nerrors;
  }
  for (int i=(int)(sizeof(jq_builtins)/sizeof(jq_builtins[0]))-1; i>=0; i--) {
    nerrors = builtins_bind_one(jq, bb, jq_builtins[i]);
    assert(!nerrors);
  }
  *bb = bind_bytecoded_builtins(*bb);
  *bb = gen_cbinding(function_list, sizeof(function_list)/sizeof(function_list[0]), *bb);
  return nerrors;
}