Suspending operations with raw_input (Python)

xadrith · 07-23-2008, 10:55 PM

This is somewhat related to my previous post requesting assistance for code that would unfold text char by char to give that movie-like intro and plotline sequencing to my text-based game.

Borrowing from Rocket357's code I have the following:

Code:

def unfold_message(msg,delay):
        try:
            delay=float(delay)
        except ValueError:
            delay=0.100
        for char in msg:
            time.sleep(delay)
            sys.stdout.write(char)
            sys.stdout.flush()
        print

This worked out perfectly, exactly what I was looking for (thanks again

)

However, I also took smoked kipper's advice in offering the user a way to "fast forward" through the scrolling, in the case of them having already read those parts and just wishing to get into the game again...

However I am having trouble with implementing user input (say to have the user press the enter button to instantly speed the scrolling) the way I want it to work.

I've tried many different ways, and some have come closer to others, my most recent attempt is this:

Code:

def unfold_message(msg,delay):
    x = True
    if x == True:
        try:
            delay=float(delay)
        except ValueError:
            delay=0.100
        for char in msg:
            time.sleep(delay)
            sys.stdout.write(char)
            sys.stdout.flush()
        print
    else:
        x = bool(raw_input())
        if x == False:
            clear()
            print msg

Not my best, but... my most recent

.

I want to be able to have the user hit enter without stopping the scrolling with a prompt for him/her to do so.

However I seem to implement it, the scrolling will always STOP, and then wait for the user's raw_input() and then will either print the whole msg, or just break up the scrolling text into smaller chunks.

I know it's something elegant and simple that is required, but I just can't seem to find it. Am I using the wrong control statements? I have tried if statements, for statements, while statements.

Somewhat still new to this, so help is definitely appreciated...

Thanks for your time,
x.D

jcookeman · 07-24-2008, 05:09 PM

What you are trying to do will be require platform-dependent code. The following will not work on Windows (and there is more than one way to do it), and you will need to use termios to handle user input not mangling the screen:

Code:

#!/bin/env python
import time
import sys
import select

def unfold_message(msg,delay):
     try:
          delay=float(delay)
     except ValueError:
          delay=0.100
     for char in msg:
            if not select.select([sys.stdin],[],[],0) == ([sys.stdin],[],[]):
                 time.sleep(delay)
            sys.stdout.write(char)
            sys.stdout.flush()
     print

if __name__ == "__main__":
     unfold_message("hello, this is a test", 0.1)