Re: [FWP] Drunk driving

[Mark-Jason Dominus <mjd@plover.com>]

> But exec's needlessly.  

Oh, gosh!

> Sorry MJD, but you missed the mark on this one.  

Yeah, I just found a new hammer, and I'm going around hammering
everything in sight, even stuff that doesn't need hammering.

> If you can write it all into a pipe buffer, you can read it in the
> same process. 

If you omit the exec, you do better than that:  You can alternate the
writes and the reads, so that only each line of output needs to fit in
the pipe.  That is a lot more likely than fitting the total of all the
data into the pipe. 

Then the program looks like this:


#!/usr/bin/perl
#
# This demonstrates a method of writing format-ed output into
# variables under Perl 4.
#
# mjd-perl-lod@plover.com

format F_OUT = 
@<<<<<<<<< | @|||||||||| | @>>>>>>>>>>          @#####.##
$left,       $center,      $right,              $numeric
.


pipe(F_IN, F_OUT) or die "pipe: $!";
select((select(F_OUT),$|=1)[0]);
for ($i=0; $i<7; $i++) {
  ($left, $center, $right) = split /\s+/, scalar <DATA>;
  write F_OUT;
  push @formatted, scalar <F_IN>;
  $numeric *= 2 / 3;
}

for ($i = 0 ; $i < @formatted; $i++) {
  print  "STDIN $i: $formatted[$i]";
}

__DATA__
In the beginning
God created the
heavens and the
Earth.  The Earth
was without form
and void, and
darkness was upon
the face of 
the deep. 




This works really well.  You could probably even install it as a
subroutine or something.




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