From: nobu.nokada@...
Date: 2004-06-24T12:04:45+09:00
Subject: Re: Cleaning up IO#popen

Hi,

At Wed, 23 Jun 2004 02:49:26 +0900,
evanm@frap.net wrote in [ruby-talk:104358]:
> > > it work? What is its args? Does it drop the '-' and mode arguments?
> > 
> > I'm not sure they are really evil.
> 
> Parsing a string for magic arguments moves logic from the code into the data.
> It's poor design. Why not have a separate function with all the benefits that
> brings? AFAIK there aren't any benefits in parsing magic values from a
> string, but if you allow "-" then the programmer has to special case every
> string he passes to verify that it's not "-" or risk running the wrong
> function.
> 
> There are many more elegant ways of doing this, but the best is to not do it
> at all.

I admit there will be better ways much.  But I'd like to
introduce a new class for child process rather than popen3.

> > At Mon, 21 Jun 2004 06:06:02 +0900,
> > evanm@frap.net wrote in [ruby-talk:104194]:
> > > * takes a "mode string" arg for what really should be a separate function
> > > * takes a "-" as a magic value for what really should be a separate function
> > 
> > Do you suggest to provide all possible combinations?
> 
> I suggest the code I submitted for IO.fork_open. There are only two
> options, reading and writing, and this can be done in one with my
> implementation of IO.fork_open which provides a bidirectional pipe.

Single pipe pair cannot be used for bidirectional, and
fork_open doesn't feel a good name for me.

-- 
Nobu Nakada