From: Stefano Crocco <stefano.crocco@...>
Date: 2008-05-30T23:03:59+09:00
Subject: getting standard error and output from ruby script in real time

I'm trying to write an editor for ruby in ruby using the KDE4 bindings for 
ruby and I'm facing a problem which I don't know whether is caused by ruby or 
by KDE. I want my editor to be able to run a ruby script and display both the 
error messages and the normal output in a window. The problem is that all the 
text sent to the standard output seems to be received together from my 
application, and so does the text sent to standard error, even if the two are 
mixed. For example, when I run the following script

5.times do |i|
  warn "Warning #{i}"
  puts i
end

the output window of my program displays this:
Warning 0
Warning 1
Warning 2
Warning 3
Warning 4
0
1
2
3
4

instead of this (which is what I get if I run the script from terminal)
Warning 0
0
Warning 1
1
Warning 2
2
Warning 3
3
Warning 4
4

Since I don't have much experience on interprocess communication, I can't, as 
I said, understand if this issue is due to the way ruby prints its output or 
to the tools I use to run the ruby script from my editor, which are specific 
of KDE. I'd be glad if someone could give me a hint on this, so that at least 
I can know whether I have to look for documentation about ruby or about KDE.

Thanks in advance

Stefano