From: Pavankumar Kulkarni <pavankumar_kulkarni@...>
Date: 2008-01-18T19:19:25+09:00
Subject: Re: Quit, if a specific key is hit

I found a platform independent solution to this in one of the comments 
of that link(below) here 
<http://www.rubyrailways.com/implementing-15-exercises-for-learning-a-new-programming-language/#comment-1145>.

i=0
loop do
begin
break if STDIN.read_nonblock(1000)
rescue Errno::EAGAIN
end
puts i
i += 1
end

Cheers,
Pavankumar Kulkarni * Software Developer * Persistent Systems Ltd 



John Joyce wrote:
>
> On Jan 17, 2008, at 7:28 AM, James Gray wrote:
>
>> On Jan 16, 2008, at 11:43 PM, Pavankumar Kulkarni wrote:
>>
>>> Excuse me, if this is already discussed... but from from here 
>>> <http://www.rubyrailways.com/implementing-15-exercises-for-learning-a-new-programming-language/>.. 
>>> the author concludes that the following problem cannot be solved.. 
>>> whats the reason?
>>> "Display series of numbers (1,2,3,4, 5....etc) in an infinite loop. 
>>> The program should quit if someone hits a specific key (Say ESCAPE 
>>> key)."
>>
>> It can definitely be solved.  Here's a solution that works on most 
>> Unix-like operating systems, for example:
>>
>>   #!/usr/bin/env ruby -wKU
>>
>>   require "io/wait"
>>
>>   state = `stty -g`
>>   begin
>>     system "stty raw -echo cbreak isig"
>>
>>     1.upto(1.0/0.0) do |n|
>>       puts n
>>       exit if $stdin.ready? and $stdin.getc == 27
>>     end
>>
>>   ensure
>>     system "stty #{state}"
>>   end
>>
>>   __END__
>>
>> What the author actually said was that it can't solve it without 
>> writing some platform specific code or threads.  I don't know how to 
>> do it without using one of those tricks either.
>>
>> The reason is that all terminals are different and you are needing to 
>> interact with it on two levels at once (reading while writing).  This 
>> is what introduces the need for the platform specific code.
>>
>> James Edward Gray II
>>
>>
> In many of the game libraries, input for different platforms is 
> addressed.
> This one of those cases where the game libraries, such as Gosu or 
> rubygame, or Ruby/SDL are going to be very useful for a non game.
> most game libs have a very fundamental need for input control, and a 
> pretty important need for crossplatform code abstraction.
> You don't need to know much about them, just enough to get the keys 
> under your control!
> But the plus is, you can also get a GUI up without much work.
>
>