Input & Ask

:input reads a line from stdin and returns it as a string. :ask is an alias — they are identical¹.

Overview

:input takes an optional prompt string. It prints the prompt without a newline, waits for the user to type a line, and returns the input with the trailing newline stripped.

Try this in the REPL:

gbln(1): name | :input("What is your name? ")
What is your name? Daniel
gbln(2): name
Daniel
gbln(3): :say "Hello, {name}!"
Hello, Daniel!

gbln(1): name | :input("What is your name? ")
What is your name? Daniel
gbln(2): name
Daniel
gbln(3): :say "Hello, {name}!"
Hello, Daniel!

Basic Usage

With a prompt

name | :input("What is your name? ")
:say "Hello, {name}!"

name | :input("What is your name? ")
:say "Hello, {name}!"

Without a prompt

line | :input()

line | :input()

Using the ask alias

name | :ask("What is your name? ")

name | :ask("What is your name? ")

Return Value

:input always returns a string. The trailing newline is stripped automatically. If the user presses Enter without typing anything, it returns an empty string "".

answer | :input("Continue? (y/n) ")
if answer == "y"
    :say "Continuing..."
xx

answer | :input("Continue? (y/n) ")
if answer == "y"
    :say "Continuing..."
xx

Non-Interactive Mode

error: R0505: non-interactive: interactive input is disabled in non-interactive mode

error: R0505: non-interactive: interactive input is disabled in non-interactive mode

Errors

Passing a non-string prompt raises a type error:

:input(42)
/// error: T0205 type-mismatch: input/ask expects the prompt to be a string

:input(42)
/// error: T0205 type-mismatch: input/ask expects the prompt to be a string

If stdin is unavailable or closed, a runtime I/O error is raised:

error: R0501: io-error: failed to read from stdin

error: R0501: io-error: failed to read from stdin