module-tty.rst

The TTY module answers whether a stream is attached to a real terminal, and how wide that terminal is.

This is the gate for anything that redraws itself with a carriage return: a progress bar written to a pipe, a redirect, or a supervising process is garbage in the resulting log. Checking TERM is not a substitute — it stays set when standard output is redirected. daslib/ansi_colors handles styling; this module answers the capability question underneath it.

All functions and symbols are in "tty" module, use require to get access to it.

require daslib/tty

Example:

require daslib/tty

[export]
def main() {
    if (is_stdout_terminal()) {
        print("drawing a {terminal_columns()}-column progress bar\n")
    } else {
        print("output is captured — emitting plain lines instead\n")
    }
}