harn-stdlib 0.8.26

Embedded Harn standard library source catalog
Documentation 
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/** std/io - interactive terminal input and stderr helpers. */
type ReadLineOptions = {prompt?: string, timeout_ms?: int, trim?: bool, echo?: bool, raw?: bool}

type ReadLineResult = {ok: bool, value?: string, status?: string, error?: string}

/**
 * is_tty returns whether fd 0, 1, or 2 is attached to a terminal.
 *
 * @effects: []
 * @allocation: stack-only
 * @errors: []
 * @api_stability: stable
 * @example: is_tty(fd)
 */
pub fn is_tty(fd: int = 0) -> bool {
  if fd == 0 {
    return is_stdin_tty()
  }
  if fd == 1 {
    return is_stdout_tty()
  }
  if fd == 2 {
    return is_stderr_tty()
  }
  throw "std/io.is_tty: fd must be 0, 1, or 2"
}

/**
 * read_line reads one line from stdin and reports ok/eof/timeout/interrupt/error.
 *
 * @effects: []
 * @allocation: heap
 * @errors: []
 * @api_stability: stable
 * @example: read_line(opts)
 */
pub fn read_line(opts: ReadLineOptions = {}) -> ReadLineResult {
  return __io_read_line(opts ?? {})
}

/**
 * read_password reads one line with terminal echo disabled.
 *
 * @effects: []
 * @allocation: heap
 * @errors: []
 * @api_stability: stable
 * @example: read_password(prompt, timeout_ms)
 */
pub fn read_password(prompt: string = "", timeout_ms: int? = nil) -> ReadLineResult {
  return read_line({prompt: prompt, timeout_ms: timeout_ms, echo: false})
}

/**
 * write_stderr writes text to stderr without appending a newline.
 *
 * @effects: []
 * @allocation: heap
 * @errors: []
 * @api_stability: stable
 * @example: write_stderr(text)
 */
pub fn write_stderr(text: string) {
  eprint(text)
}