From: Klaus Spreckelsen <klaus.spreckelsen@...>
Date: 2003-05-13T23:53:19+09:00
Subject: Re: RCR for child execution

Aredridel wrote:

> On Mon, 2003-05-12 at 17:57, nobu.nokada@softhome.net wrote:
>> Hi,
>> 
>> At Tue, 13 May 2003 08:47:36 +0900,
>> ahoward wrote:
>> > > I don't like this notation.  But I like the idea of spawning child
>> > > with its stdin/out/err replaced.

>> > spawn 'command', :out => io, :err => io
>> 
>>   spawn ['command', 'arg1', 'arg 2'], :out => io, :err => io
> 
> spawn 'command' do
> out = io
> err = io
> end.run                        =>  <#ExternalProc:0x0000>
> 
> -- make it a full block, so that it's easily extensible.  spawn could be
> a factory for ExternalProc objects (an alias for ExternalProc.new?).

Some months ago, I have written an class just for this purpose.

Simple example:


require "cp"

x = ConnectedProcess.new("cat") do |i, o, e|
  $stdin.reopen i
  $stdout.reopen o
end
x.start
x.stdin.puts "hello"
puts x.stdout.gets     # -> hello


x = ConnectedProcess.popen2("ls", "not_there") do |i, o, _, pid|
  puts "Process #{pid}: #{o.gets}" 
        # -> Process 17245: ls: not_there: No such file or directory
end


You can find the class an the demo under 
http://www.tp1.ruhr-uni-bochum.de/~ks/cp/

Unfortunatly, the documentation is currently available only in German.

Klaus Spreckelsen