terminal

Build terminal UIs: query the terminal, switch stdin to raw mode, read individual keystrokes, and generate ANSI escape sequences for color, cursor, and screen control. Import it with import terminal.

State and input

Function	Signature	Description
`isatty`	`terminal.isatty() → bool`	Whether stdout is a terminal
`size`	`terminal.size() → object`	Terminal dimensions as `{cols, rows}` (defaults to 80x24 if unavailable)
`rawMode`	`terminal.rawMode() → int`	Switch stdin to raw mode (no echo, no line buffering); returns a state handle, or `-1` on error
`restoreMode`	`terminal.restoreMode(handle: int) → bool`	Restore the mode saved by `rawMode`
`readKey`	`terminal.readKey() → string`	Read one keystroke; returns a key name (see below) or a single printable character
`write`	`terminal.write(s: string) → bool`	Unbuffered write to stdout with no trailing newline — use for mid-frame ANSI sequences
`flush`	`terminal.flush() → void`	Flush pending stdout output

readKey returns names like up, down, left, right, enter, tab, esc, backspace, home, end, pageup, pagedown, insert, delete, f1–f12, and ctrl+a–ctrl+z.

Cursor and screen

These return ANSI escape-sequence strings to pass to terminal.write.

Function	Signature	Description
`clear`	`terminal.clear() → string`	Clear screen and home the cursor
`clearLine`	`terminal.clearLine() → string`	Clear the entire current line
`clearRight`	`terminal.clearRight() → string`	Clear from cursor to end of line
`hideCursor`	`terminal.hideCursor() → string`	Hide the cursor
`showCursor`	`terminal.showCursor() → string`	Show the cursor
`altScreen`	`terminal.altScreen() → string`	Enter the alternate screen buffer
`mainScreen`	`terminal.mainScreen() → string`	Leave the alternate screen buffer
`saveCursor`	`terminal.saveCursor() → string`	Save the cursor position
`loadCursor`	`terminal.loadCursor() → string`	Restore the saved cursor position
`moveTo`	`terminal.moveTo(row: int, col: int) → string`	Move cursor to a 1-indexed position

Styling and color

Function	Signature	Description
`reset`	`terminal.reset() → string`	Reset all attributes
`bold`	`terminal.bold() → string`	Bold
`dim`	`terminal.dim() → string`	Dim
`italic`	`terminal.italic() → string`	Italic
`underline`	`terminal.underline() → string`	Underline
`reverse`	`terminal.reverse() → string`	Reverse video
`color`	`terminal.color(name: string) → string`	Foreground color by name (`red`, `green`, …, `brightblue`, `default`) or a `"0"`–`"255"` string for 256-color
`bg`	`terminal.bg(name: string) → string`	Background color, same names
`rgb`	`terminal.rgb(r: int, g: int, b: int) → string`	24-bit truecolor foreground
`bgRgb`	`terminal.bgRgb(r: int, g: int, b: int) → string`	24-bit truecolor background

Example

import terminal

// switch to raw mode and read keys until Esc
let st = terminal.rawMode()
terminal.write(terminal.clear())

let running = true
while running {
  let key = terminal.readKey()
  if key == "esc" {
    running = false
  } else {
    // print the key in green at the top-left
    terminal.write(terminal.moveTo(1, 1) + terminal.clearLine())
    terminal.write(terminal.color("green") + "key: " + key + terminal.reset())
    terminal.flush()
  }
}

terminal.restoreMode(st)

Standard library · View as Markdown · llms-full.txt