How to recognize space or enter as one-character input?

[Mark17]

The input function returns what the user typed up to but not including the final enter. So if they just hit enter, and empty string ('') will be returned. If they hit space + enter, a space character will be returned (' ').

If they just hit space without hitting enter, input will sit there waiting for them to hit enter.

Is there an altogether different command that solicits input and records it without the "final enter?"

I've seen programs in the past (language unknown) that will say things like "enter Y or N" and proceed once that first keystroke (Y or N) is pressed. That's what I'm trying to do.