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by pryrt (Chaplain)
on Mar 18, 2016 at 23:38 UTC ( #1158292=user: print w/replies, xml ) Need Help??

Hobbyist Perl s‎crip‎ts since the mid '90's, when I picked it up to start doing some simple cgi and random .sig picker for my college-supplied email and personal homepage.

Since my searches for Perl questions usually had the best answer here, I decided I'd finally make an account, and see if I could occasionally answer something rather than just having all my questions answered. :-)

Recently took over Games::Literati, because it'd had a long-time scoring bug, and I wanted to add some features (like Words With Friends).

Developing Data::IEEE754::Tools because I'm interested in the underlying encoding of floating-point numbers, and because Integers sometimes turn into Reals after substraction started an Earworm, fed by Determining the minimum representable increment/decrement possible?, that then wouldn't go away.

Developing Math::PRBS because sometimes, a PRBS is useful to have, and I was surprised to find that I couldn't see it in Math::NumSeq (under any name that I could think of); even if it does include it, one of its prerequisite libraries doesn't compile on Win32 systems. So, I made one.

Posts by pryrt
"executable suffixes" for -x on win32 (perlport) in Seekers of Perl Wisdom
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by pryrt
on Apr 25, 2017 at 17:27

    Regarding the executable-test -x, perlport says:

    -x (or -X) determine if a file ends in one of the executable suffixes. -S is meaningless. (Win32)

    Where are the "executable suffixes" defined for Win32 perl (strawberry, in my case)? If anything, I would have expected $ENV{PATHEXT}, because that's the closest related idea to "executable" on windows (or possibly the assoc and ftype and their underlying registry entries -- though that's more complicated). However, I've got ".pl" in my PATHEXT variable and properly associated in the registry, but -x "$0" results in a false value (undef). I also tried with a .js file, which is in the Windows-default PATHEXT, but it shows up as non-executable as well. I've experimentally found that .com, .exe, .bat, and .cmd all show up as executable... but none of the others in the default PATHEXT=.COM;.EXE;.BAT;.CMD;.VBS;.VBE;.JS;.JSE;.WSF;.WSH;.MSC


    context: after reading Re^2: how do i run a shell command without waiting for the output, I looked at Proc::Background, and saw that commands were "checked by appending `.exe' to the name in case the name was passed without the `.exe' suffix". Since ".exe" isn't the only extension dropped on Win32 (PATHEXT defines the extension-omission properties for Win32, and .bat is frequently untyped as well), I wanted to suggest a bugfix to allow any extension from PATHEXT: change the hardcoded push(@extensions, '.exe'); to push @extensions, split(/;/, $ENV{PATHEXT} || '.exe');. However, while testing my change against various extensions (explicit or omitted-but-implied), I found that Proc::Background wasn't getting as far as using the @extensions array, since -x was failing. I found the quoted perlport description that Win32 -x has a list of extensions, but I haven't found the official documentation for what that list is (and really, if there's any hardcoded list embedded in the perl ports to Win32, I disagree with them on the same grounds that I disagree with Proc::Background)

    edit: add <readmore> tags...

binmode i/o for perl -pi in-place editing in Seekers of Perl Wisdom
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by pryrt
on Dec 07, 2016 at 18:24

    how do you set binmode for the input and output of a perl -pi *.file in-place edit? I had hoped by doing binmode ${^LAST_FH}; binmode STDOUT;, that would cover it...

    I've gotten the input as close to binmode as I can, in that for the sample input above, the sum of the lengths of $_ totals 61, which matches that example input. But putting binmode STDOUT in either the BEGIN, the main, or both, does not seem to help the output file be the same length. I tried perl -C0 -pi... (from perlrun), hoping to make it all :raw equivalent, but with no change. I looked thru perlvar to try to find an output-equivalent of ${^LAST_FH}, but didn't see anything.

    In the end, I'll probably just stop trying the magic perl -pi and make a manual in-place loop, where I open the ARGV input and output handles myself, so I have full control. But after this much investigation, I'd really like to find out if it's possible to make the whole in-place pipeline binmode.

    ps: No, converting 'w' to 'v' is not my end goal :-). I just used that as a SCCE to show the basic problem binmode issue: I want to be able to do all my working (where my actual manipulations will preserve byte-length) without changing the EOL-like characters for this binary file.

detached threads still warn in Seekers of Perl Wisdom
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by pryrt
on Oct 07, 2016 at 11:36

    So, I started playing around with threads, using Re: buffering zipped pipes as an example. I got something working on my Windows machine, then tried it out on the ancient linux box (perl 5.8.5)... and got the dreaded "A thread exited while 2 threads were running."

    I double-checked to make sure that the linux box's perldoc threads claimed support for ->detach, and the WARNINGS section suggested joining to remove the error. I thought ->detach was supposed to make it automatically clean up such stuff.

    I tried no warnings 'threads'; or even no warnings;, just to see if I could make the warning go away, but it stuck around.

    Given the details (below), how can I get around this warning? Can I install a new local version of threads on the linux machine (I have cpan set up for local library installs), or is threads too core to be able to update with cpan? Or should I just switch to not using ->detach, and do manual cleanup using ->join?

    tl;dr details follow...

Advice wanted for debugging CPAN Testers failures in Seekers of Perl Wisdom
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by pryrt
on Aug 23, 2016 at 11:59
    Fellow Monks,

    How do you go about debugging failures from CPAN Testers when your own configurations are not failing? I'd like advice, both in general, and anything you see in my specific examples below.

    For example, this test matrix has a bunch of failures -- but when I test on my machines, I cannot replicate the errors they are getting.

    Before releasing, I tested on a couple of different versions I have access to (strawberry perl 5.24.0_64 on Win7 and an ancient CentOS 4.6 linux 2.6.9-55 with perl 5.8.5), and neither failed my test suite. And since I've seen the CPAN Testers failures, I've started increasing my berrybrew installations to improve version coverage -- but so far, they've all passed, even when they've been on Perl versions that failed in the linux column.

    After I've exhausted available Strawberry installations, I will probably grab one of my linux virtual machines and start increasing perlbrew installations, and run through as many as I can there (I cannot install perlbrew or other local perls on the CentOS machine I noted, due to disk restrictions). But even with trying a new slew of versions, I cannot guarantee that I'll see the same failures that CPAN Testers is showing me.

    I know where I'll be looking for the specific errors: my expected values are wrong; the expected values were being generated by functions I thought were fully tested earlier in my test suite, so I'll have to look into that some more, and also see if maybe I should independently generate the expected values.

    But if I cannot replicate the exact failures from CPAN Testers, it's going to be harder to know I've solved the problem. When doing my last release to add features, I ended up submitting beta versions to CPAN, with extra debug printing, and waiting overnight while the CPAN Testers ran, then basing my fixes on changes in those results. But that's a rather slow debug process... and I noticed that every submission, I was getting fewer results from TESTERS: I think some of those auto-testers have some sort of submission limits, or otherwise remember that a particular module fails and stops testing new versions.

    Any advice, generic or specific, would be welcome.

unintentional conversion of signaling NaN to quiet NaN in Seekers of Perl Wisdom
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by pryrt
on Jun 23, 2016 at 16:48

    Harkening back to my experiments to make an to interpret IEEE754 doubles, I found when making my tests that as I converted a signaling NaN bit string into a double then back to the bit string, it became a quiet NaN. At first I thought I just had a bug in my conversion, so then I tried BrowserUK's code from Re^2: Exploring IEEE754 floating point bit patterns., along with a new function to convert it back.


    ... ie, it fails on just the signaling NaN, appearing like a quiet NaN bitstring.

    I tried under an ancient CentOS 4.6 perl 5.8.5, and under a recent Strawberry 5.22.1 32bit, and get the same quieting of the sNaN. Am I doing something wrong, or does perl just automatically quiet signalling NaN values?

open('<&'), Perl::MinimumVersion, and my test suite in Seekers of Perl Wisdom
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by pryrt
on Apr 05, 2016 at 12:26

    Fellow Monks, when I released Games::Literati 0.032, I discovered the hard way (thanks, CPAN Testers) that in-memory files are not compatible with Perl 5.6. The module itself doesn't use in-memory files, but part of my test suite did. So I reworked the test suite to not use in-memory files. I then found Perl::MinimumVersion 1.38, and ran perlver on my module and test files, and all claimed to be Perl 5.6.0 compatible. However, when I released Games::Literati 0.040, I was surprised to see CPAN Testers flag me for failure when tested under Perl 5.6.2. :-(

    tl;dr summary

    1. What Perl version introduced open() using '<&'? I know that by 5.8.5, it works, and apparently it doesn't in 5.6.2.
    2. Should I consider it a bug in Perl::MinimumVersion 1.38 that perlver claimed my test suite was compatible with 5.6.0?
    3. Should I just skip the portions of my test suite that require the '<&'? Or should I try to find an alternate?
    4. Easy way to get 5.6.0 on Windows? (Alternately, pre-made virtual machine with 5.6.0?)

    tl;dr details

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