Solving Deep recursion with a tied Filehandle

cog has asked for the wisdom of the Perl Monks concerning the following question:

My most esteemed monks.

Here's some code:

package FileHandle::A;

sub TIEHANDLE {
  my $self =   shift  ;
  my $fh   = [ shift ];
  bless \$fh => $self;
}

sub PRINT {
  my $self = shift;
  my @list = @_;

  my $fh = $$self->[0];
  print $fh @list;
}

tie *STDOUT, 'FileHandle::A', *STDOUT;

print "testing";
[download]

Basically, I was getting a Deep recursion error and I tried minimalizing the error to post here. The code I present here segfaults on my machine.

I think I know why... PRINT calls print which calls PRINT which calls print which calls... you get the idea...

I tried a bunch of things already, including CORE::print() and even passing a special parameter to stop the recursion, which indeeds stops it, but... doesn't print.

I know the example looks weird; it really isn't what I want to do, but it demonstrates my problem. Can anyone point me in a direction that solves it?

Comment on Solving Deep recursion with a tied Filehandle Download Code

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Re: Solving Deep recursion with a tied Filehandle by runrig (Abbot) on Oct 14, 2005 at 16:53 UTC
As mentioned in the CB, your code works in 5.6.1 and earlier, but not 5.8.??? However, I did get this to work in 5.8.4: `FH = STDOUT; { local STDOUT; tie STDOUT, 'FileHandle::A', FH; print "testing"; }` [download] Update: Just a note that the local above doesn't seem to do what I thought it would, that is, after the anonymous block, STDOUT is still tied (I thought it would get untied and return to it's original state). I think the correct thing would be to untie STDOUT (and maybe set it to the saved FH) when you want the old STDOUT back. That still doesn't help cog, though :(	[reply] [d/l]
Re^2: Solving Deep recursion with a tied Filehandle by ikegami (Patriarch) on Oct 14, 2005 at 18:39 UTC
If you don't want it to localize STDOUT, the following works: `{ local TEMP = STDOUT; undef(STDOUT); tie STDOUT, 'FileHandle::A', TEMP; } print "testing";` [download] and so does `{ my $temp = STDOUT; undef(STDOUT); tie STDOUT, 'FileHandle::A', $temp; } print "testing";` [download] Tested on Perl 5.6.1 and 5.8.0	[reply] [d/l] [select]
Re^3: Solving Deep recursion with a tied Filehandle by cog (Parson) on Oct 15, 2005 at 18:03 UTC
None of those work with my 5.8.7	[reply]
Re^4: Solving Deep recursion with a tied Filehandle by ikegami (Patriarch) on Oct 15, 2005 at 22:21 UTC
Re^5: Solving Deep recursion with a tied Filehandle by cog (Parson) on Oct 16, 2005 at 14:17 UTC
Some notes below your chosen depth have not been shown here
Re^2: Solving Deep recursion with a tied Filehandle by cog (Parson) on Oct 14, 2005 at 16:58 UTC
That doesn't segfault anymore, but neither does it print and it seems to run endlessly, while hanging my machine. I'm running 5.8.7.	[reply]
Re: Solving Deep recursion with a tied Filehandle by Anonymous Monk on Oct 14, 2005 at 17:00 UTC
Don't do that	[reply]