ludic/packages/ludic.i18n/keyed_render.ludic

# keyed_render.ludic - a marked string made into text where it is drawn: its key looked up (a plural's by
# its count), its holes filled with its arguments, each argument that is itself a key made first

# what L does with a key: made once per distinct marked string in this language, then kept
function keyed(i18n_st: mut I18nState, s: string) -> string {
  if i18n_st.kc == null { kc_clear(i18n_st) }
  let ci = Dict.get_or(i18n_st.kc, s, -1)
  if ci >= 0 { return i18n_st.kc_out[ci] }
  let r = kr_make(i18n_st, s)
  if Dict.size(i18n_st.kc) >= CACHE_MAX { kc_clear(i18n_st) }
  @alloc_ok("a key made into text: the result kept, up to CACHE_MAX")
  Dict.set(i18n_st.kc, s, len(i18n_st.kc_out))
  @alloc_ok("a key made into text: as above")
  push(i18n_st.kc_out, r)
  return r
}

# a language's change makes every kept text stale
@alloc_ok("on a language change: the made keys let go")
function kc_clear(i18n_st: mut I18nState) -> void {
  i18n_st.kc = Dict.new()
  i18n_st.kc_out = new []string
}

@alloc_ok("a key made into text (a cache miss): once per distinct marked string")
function kr_make(i18n_st: mut I18nState, s: string) -> string {
  let args = new []string
  var start = 1
  var i = 1
  while i <= len(s) {
    if i < len(s) and s[i] == I18N_ESC {
      i += 2                                # an escaped byte belongs to its argument
      continue
    }
    if i >= len(s) or s[i] == I18N_SEP {
      var e = i
      if e > len(s) { e = len(s) }
      push(args, kr_unescape(s[start..e]))
      start = i + 1
    }
    i += 1
  }
  let key = args[0]
  var t = ""
  if s[0] == I18N_PLURAL and len(args) > 1 { t = kb_plural(i18n_st, key, kr_int(args[1])) } else { t = kb_text(i18n_st, key) }
  return kr_fill(i18n_st, t, args)
}

# {k} is argument k (args[0] is the key); a missing one is empty, a key is made into its own text
@alloc_ok("a key made into text (a cache miss): its holes filled")
function kr_fill(i18n_st: mut I18nState, t: string, args: []string) -> string {
  var r = ""
  var seg = 0
  var i = 0
  while i < len(t) {
    let h = hole_at(t, i)
    if h >= 1 {
      var v = ""
      if h < len(args) { v = args[h] }
      if i18n_is_key(v) or kx_mixed(v) { v = L(i18n_st, v) } else if i18n_st.on and kr_words(v) { v = L(i18n_st, v) }
      r = r + t[seg..i] + v
      i = hole_end(t, i)
      seg = i
      continue
    }
    i += 1
  }
  return r + t[seg..len(t)]
}