harn-stdlib 0.10.49

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: []
 * @errors: []
 */
pub fn is_tty(term: HarnessTerm, fd: int = 0) -> bool {
  if fd == 0 {
    return term.is_tty("stdin")
  }
  if fd == 1 {
    return term.is_tty("stdout")
  }
  if fd == 2 {
    return term.is_tty("stderr")
  }
  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: []
 * @errors: []
 */
pub fn read_line(stdio: HarnessStdio, opts: ReadLineOptions = {}) -> ReadLineResult {
  return stdio.read_line(opts ?? {})
}

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

/**
 * write_stdout writes text to stdout without appending a newline.
 *
 * @effects: []
 * @errors: []
 */
pub fn write_stdout(stdio: HarnessStdio, text: string) {
  stdio.print(text)
}

/**
 * write_stderr writes text to stderr without appending a newline.
 *
 * @effects: []
 * @errors: []
 */
pub fn write_stderr(stdio: HarnessStdio, text: string) {
  stdio.eprint(text)
}