Prompt with PROMPT. Whitespace terminates the input. If INITIAL is
non-nil, it should be a string, which is used as initial input, with
point positioned at the end, so that SPACE will accept the input.
Prompt with PROMPT. Whitespace terminates the input. If INITIAL is
non-nil, it should be a string, which is used as initial input, with
point positioned at the end, so that SPACE will accept the input.