# lib_util.ludic - a file made, found, read, and a path beside another (or from the project's
# root, when it starts with /)
function lib_find(names: []string, name: string) -> int {
  for i in 0 .. len(names) {
    if names[i] == name { return i }
  }
  return -1
}
function lib_new(ui_st: mut UiState, path: string) -> UiFile {
  let f = lib_blank(path)
  push(ui_st.lib_files, f)
  return f
}
# a file that is not one of the loaded ones (a component's own)
function lib_blank(path: string) -> UiFile {
  let f = new UiFile
  f.path = path
  f.names = new []string
  f.comps = new []UiTpl
  f.exported = new []bool
  f.imp_as = new []string
  f.imp = new []UiFile
  f.own = new []UiRule
  return f
}
function lib_text(ui_st: UiState, path: string) -> string {
  let o = ov_find(ui_st, path)
  if o >= 0 { return `{ui_st.ov_text[o]}` }   # a copy: a caller may give back what it read (rl_let_go)
  var src = ""
  if ui_st.ui_be != null and ui_st.ui_be.read != null { src = ui_st.ui_be.read(path) } else { src = Fs.read_text(path) }
  if src == null { return "" }
  return src
}
# `src` read from beside the file that imports it
function lib_beside(path: string, src: string) -> string {
  var cut = -1
  for i in 0 .. len(path) {
    if path[i] == 47 { cut = i }
  }
  if len(src) > 0 and src[0] == 47 { return src[1..len(src)] }
  if cut < 0 { return src }
  return path[0..cut + 1] + src
}
# `s` has `p` starting at `at`: compared in place, where s[at..at + len(p)] == p made a new string
# for every place it looked (Ludic frees nothing, and the cascade asks this per element per frame)
function sat(s: string, at: int, p: string) -> bool {
  let n = len(p)
  if at < 0 or at + n > len(s) { return false }
  for i in 0 .. n {
    if s[at + i] != p[i] { return false }
  }
  return true
}