Re: [PATCH] Modernize, improve and/or extend tests `colon*.test.

[Stefano Lattarini]

At Sunday 08 August 2010, Ralf Wildenhues wrote:
> * Stefano Lattarini wrote on Sun, Aug 08, 2010 at 06:06:04PM CEST:
> > At Sunday 08 August 2010, Ralf Wildenhues wrote:
> > > No.  You save a fork with
> > > 
> > >   foo ()
> > >   {
> > >   
> > >     ...
> > >     foo_result=bar
> > >   
> > >   }
> > >   
> > >   foo ARG...
> > >   test "$foo_result" = ...
> > 
> > Yes, but how do you get foo_result in our case? ;-)
> 
> With sed, of course.
Exactly! So:
  foo() { foo_result=`sed ...`; }
  foo; bar=$foo_result;
instead of:
  foo() { sed ...; }
  bar=`foo`
Where is the significant improvement?

> > Or am I missing something?
> 
> I think you are.  You proposed
>   result=`foo ...`
>   test "$result" = ...
> which is an extra fork over the above, regardless of what foo does
> internally.
Even considering my latest example above?

I'd like to sort this out, since if I am mistaken it means that I'm 
probably misunderstanding something important...

Regards,
  Stefano

P.S. I'm delibrately ignoring that we might also want to just
redirect the output of foo() to a file, which means that:
 foo() { foo_result=`sed ...`; }
would lead us to extra useless forks *and* to extra coding
indirections, i.e.:
 foo; echo "$foo_result" > file
instead of:
 foo > file