how to use angle operator with timeout?

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

Hello, (I am not sure if this is a Perl question, or is more a general programming question. If the latter, then I am sorry to post here, please say so and I will begone. )

Every child in kindergarten knows what this does:

while (<>) {
  process $_
}
[download]

What I want, is to get into the loop not only when a new line arrives, but also, after 1 second of waiting for it, (in which case $_ should be empty). I am thinking along the lines of fork or something, but it's going to be somewhat ugly. Is there a nice "monk" way to do this? Thank you, Mark

Comment on how to use angle operator with timeout? Download Code

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Re: how to use angle operator with timeout? by tobyink (Canon) on Feb 03, 2013 at 23:35 UTC
Try Prompt::Timeout or IO::Prompter. The basic technique just involves the `alarm` function... `use 5.010; use strict; use warnings; use Try::Tiny; my $line; try { local $SIG{ALRM} = sub { die "ALARM\n" }; alarm 10; say "Please enter some text, but quick!"; $line = <>; chomp $line; alarm 0; } catch { my $e = shift; $e =~ /^ALARM/ ? warn("timeout\n") : die($e); }; say "Got: '$line'";` [download] `package Cow { use Moo; has name => (is => 'lazy', default => sub { 'Mooington' }) } say Cow->new->name`	[reply] [d/l] [select]
Re^2: how to use angle operator with timeout? by BrowserUk (Patriarch) on Feb 03, 2013 at 23:55 UTC
Does that work on *nix? Cos it never times out on Windows. With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday' Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice.	[reply]
Re^3: how to use angle operator with timeout? by Anonymous Monk on Feb 04, 2013 at 00:50 UTC
http://perldoc.perl.org/perlport.html#alarm Emulated using timers that must be explicitly polled whenever Perl wants to dispatch "safe signals" and therefore cannot interrupt blocking system calls. (Win32)	[reply]
Re^4: how to use angle operator with timeout? by BrowserUk (Patriarch) on Feb 04, 2013 at 01:37 UTC
Re^5: how to use angle operator with timeout? by tmharish (Friar) on Feb 04, 2013 at 09:12 UTC
Some notes below your chosen depth have not been shown here
Re^5: how to use angle operator with timeout? by Anonymous Monk on Feb 04, 2013 at 02:39 UTC
Some notes below your chosen depth have not been shown here
Re^3: how to use angle operator with timeout? by tobyink (Canon) on Feb 04, 2013 at 15:07 UTC
"Does that work on nix? Cos it never times out on Windows."* Works for me (on Linux). `package Cow { use Moo; has name => (is => 'lazy', default => sub { 'Mooington' }) } say Cow->new->name`	[reply]
Re^2: how to use angle operator with timeout? by Mark_Galeck (Novice) on Feb 05, 2013 at 08:19 UTC
Thank you Monks very much, I appreciate your help! Yes this does work for me. Thank you!	[reply]
Re: how to use angle operator with timeout? by Mr. Muskrat (Canon) on Feb 04, 2013 at 18:55 UTC
Every child in kindergarten knows what this does: `while (<>) { process $_ }` [download] Don't I wish!	[reply] [d/l]
Re: how to use angle operator with timeout? by Khen1950fx (Canon) on Feb 05, 2013 at 07:23 UTC
I couldn't get alarm to work for me in a consistent manner, so I tried Tie::Scalar::Timeout. `#!/usr/bin/perl -l use strict; use warnings; use Tie::Scalar::Timeout; tie my $line, 'Tie::Scalar::Timeout', EXPIRES => '+1s', POLICY => undef; $line = system("whoami"); while (defined($_ = $line)) { foreach $line(my @lines) { print "$_" or die $@; } }` [download]	[reply] [d/l]
Re^2: how to use angle operator with timeout? by Anonymous Monk on Feb 05, 2013 at 07:50 UTC
couldn't get alarm .... What has that nonsense got to do with readline, ie the OPs question?	[reply]

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