hakorune/lang/src/shared/json/utils/json_frag.hako

// json_frag.hako — JSON v0 断片抽出ユーティリティ（Box）
// 責務: 文字列JSONから key:int / key:str を簡便に取り出す。
// 非責務: 実行・評価（構造検査やVM実行は他箱に委譲）。

using selfhost.shared.json.core.json_cursor as JsonCursorBox
using selfhost.shared.common.string_helpers as StringHelpers

static box JsonFragBox {
  // 基本ヘルパ - VM fallback implementations for cross-box static calls
  index_of_from(hay, needle, pos) {
    // VM fallback: implement using substring + indexOf
    if hay == null || needle == null { return -1 }
    local s = "" + hay
    local n = s.length()
    local p2 = pos
    if p2 < 0 { p2 = 0 }
    if p2 >= n { return -1 }
    // Extract substring from pos onwards
    local substr = s.substring(p2, n)
    // Find needle in substring
    local idx = substr.indexOf(needle)
    if idx < 0 { return -1 }
    return p2 + idx
  }
  read_digits(text, pos) { return StringHelpers.read_digits(text, pos) }
  _str_to_int(s) { return StringHelpers.to_i64(s) }
  _to_bool10(ch) { if ch == "t" { return 1 } if ch == "f" { return 0 } return null }

  // Read helpers (pos-based)
  read_int_from(text, pos) {
    if text == null { return null }
    local s = "" + text
    local i = pos
    local n = s.length()
    loop(i < n) { if s.substring(i,i+1) != " " { break } i = i + 1 }
    local j = i
    if j < n && (s.substring(j,j+1) == "-" || s.substring(j,j+1) == "+") { j = j + 1 }
    local had = 0
    loop(j < n) {
      local ch = s.substring(j,j+1)
      if ch >= "0" && ch <= "9" { had = 1 j = j + 1 } else { break }
    }
    if had == 0 { return null }
    return s.substring(i, j)
  }
  read_bool_from(text, pos) {
    if text == null { return null }
    local s = "" + text
    local i = pos
    local n = s.length()
    loop(i < n) { if s.substring(i,i+1) != " " { break } i = i + 1 }
    if i < n { return me._to_bool10(s.substring(i,i+1)) }
    return null
  }
  read_string_from(text, pos) {
    if text == null { return null }
    local s = "" + text
    local i = pos
    local n = s.length()
    // Find opening quote
    loop(i < n) { if s.substring(i,i+1) == "\"" { i = i + 1 break } if s.substring(i,i+1) != " " { break } i = i + 1 }
    local j = i
    loop(j < n) { if s.substring(j,j+1) == "\"" { break } j = j + 1 }
    if j <= i { return null }
    return s.substring(i, j)
  }
  read_float_from(text, pos) {
    if text == null { return null }
    local s = "" + text
    local i = pos
    local n = s.length()
    loop(i < n) { if s.substring(i,i+1) != " " { break } i = i + 1 }
    local j = i
    if j < n && (s.substring(j,j+1) == "+" || s.substring(j,j+1) == "-") { j = j + 1 }
    local had = 0
    loop(j < n) {
      local ch = s.substring(j,j+1)
      if (ch >= "0" && ch <= "9") || ch == "." { had = 1 j = j + 1 } else { break }
    }
    if had == 0 { return null }
    return s.substring(i, j)
  }

  // Read helpers (key-based, start at keyPos)
  read_int_after(text, key_pos) { return me.read_int_from(text, key_pos) }
  read_bool_after(text, key_pos) { return me.read_bool_from(text, key_pos) }
  read_string_after(text, key_pos) { return me.read_string_from(text, key_pos) }
  read_float_after(text, key_pos) { return me.read_float_from(text, key_pos) }

  // key に続く数値（最初の一致）を返す。見つからなければ null。
  get_int(seg, key) {
    local pat1 = "\"" + key + "\":"
    local p = me.index_of_from(seg, pat1, 0)
    if p >= 0 {
      // tolerant: skip whitespace and optional sign
      local v = me.read_int_after(seg, p + pat1.length())
      if v != null { return me._str_to_int(v) }
    }
    return null
  }

  // Scan for closing quote (VM fallback for scan_string_end)
  _scan_string_end(text, quote_pos) {
    // quote_pos is the position of opening quote
    // Return position of closing quote, or -1 if not found
    if text == null { return -1 }
    local s = "" + text
    local n = s.length()
    local i = quote_pos + 1
    loop(i < n) {
      local ch = s.substring(i, i+1)
      if ch == "\"" { return i }
      if ch == "\\" {
        i = i + 1  // Skip escaped character
        if i >= n { return -1 }
      }
      i = i + 1
    }
    return -1
  }

  // Seek matching closing bracket (VM fallback for seek_array_end)
  _seek_array_end(text, lbracket_pos) {
    // lbracket_pos is the position of '['
    // Return position of matching ']', or -1 if not found
    if text == null { return -1 }
    local s = "" + text
    local n = s.length()
    local depth = 0
    local i = lbracket_pos
    local in_str = 0
    loop(i < n) {
      local ch = s.substring(i, i+1)
      if in_str == 1 {
        if ch == "\"" { in_str = 0 }
        if ch == "\\" { i = i + 1 }  // Skip escaped char
      } else {
        if ch == "\"" { in_str = 1 }
        if ch == "[" { depth = depth + 1 }
        if ch == "]" {
          depth = depth - 1
          if depth == 0 { return i }
        }
      }
      i = i + 1
    }
    return -1
  }

  // key に続く "..." の文字列（最初の一致）を返す。見つからなければ空文字。
  get_str(seg, key) {
    local pat = "\"" + key + "\":\""
    local p = me.index_of_from(seg, pat, 0)
    if p >= 0 {
      local vstart = p + pat.length()              // start of value (right after opening quote)
      local vend = me._scan_string_end(seg, vstart - 1)
      if vend > vstart { return seg.substring(vstart, vend) }
    }
    return ""
  }



  // Strict variants: emit an error when the key is missing
  get_int_strict(seg, key) {
    local v = me.get_int(seg, key)
    if v == null {
      print("[ERROR] Missing key: " + key)
    }
    return v
  }

  get_str_strict(seg, key) {
    local v = me.get_str(seg, key)
    if v == "" {
      print("[ERROR] Missing key: " + key)
    }
    return v
  }
  // ブロック0の instructions を丸ごと返す（配列の中身のみ返す）。
  block0_segment(mjson) {
    if mjson == null { return "" }
    // Find the instructions array start reliably
    local key = "\"instructions\":["
    local pk = mjson.indexOf(key)
    if pk < 0 { return "" }
    // '[' position
    local arr_bracket = pk + key.length() - 1
    // Use escape-aware scanner to find matching ']'
    local endp = me._seek_array_end(mjson, arr_bracket)
    if endp < 0 { return "" }
    return mjson.substring(arr_bracket + 1, endp)
  }


  // Alias for legacy/buggy resolvers that drop underscores in method names.
  // Keep as a thin forwarder to preserve strict naming in source while
  // unblocking runtimes that accidentally call `block0segment`.
}