in reply to Re^5: Removing AUTOLOAD from CGI.pm
in thread Removing AUTOLOAD from CGI.pm

Hi

I wasn't criticizing CGI but trying to analyze the conditions for a new HTML DSL module. :)

I'm sure compilation speed shouldn't matter when generating closures. (I will add a benchmark later this day)

But CGI was designed for Perl 4 and I suppose Perl 4 wasn't able to closure... IIRC it didn't even have lexical variables.

Your wibble-tag is implemented as a method call, so it wouldn't depend on exporting and pre declaration anyway.

But DSLs are at the very least just syntactic sugar to avoid method calls.

> Anyway it's all gone now, or soon will be

Thanks for your work! :)

Cheers Rolf
(addicted to the Perl Programming Language and ☆☆☆☆ :)

PS: Je suis Charlie!

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Re^7: Removing AUTOLOAD from CGI.pm (closure vs eval)
by LanX (Saint) on Feb 24, 2015 at 14:19 UTC
    > I'm sure compilation speed shouldn't matter when generating closures. (I will add a benchmark later this day)

    Here a simplified example which showed that installing subs with closures¹ is 5 times faster than eval.

    That's less dramatic than I thought, but eval performance also heavily depends on the length of code.

    So adding 10 no-ops already made eval 10 times slower while closure didn't change.

    use strict;
use warnings;
use Time::HiRes qw/time/;


BEGIN {
    $\="\n";
    my $count=1000;
    sub noop { };
    
    my $start=time;
    sub tag_gen {
        my ($tag)=@_;
        sub {
            noop("Ipse Lorum");
            noop("Ipse Lorum");
            noop("Ipse Lorum");
            noop("Ipse Lorum");
            noop("Ipse Lorum");
            noop("Ipse Lorum");
            noop("Ipse Lorum");
            noop("Ipse Lorum");
            noop("Ipse Lorum");
            noop("Ipse Lorum");
            "<$tag>",@_,"</$tag>";
        }
    }
    {
        no strict 'refs';
        for my $x (1..$count) {
            
            my $tag="h$x";
            *{$tag}=tag_gen($tag);
        }
    }
    print "Closure: ",time-$start;

    
    $start = time;
    for my $x (1..$count) {
        my $tag="H$x";
        eval sprintf <<'__CODE__', $tag;
        sub %1$s {
            noop("Ipse Lorum");
            noop("Ipse Lorum");
            noop("Ipse Lorum");
            noop("Ipse Lorum");
            noop("Ipse Lorum");
            noop("Ipse Lorum");
            noop("Ipse Lorum");
            noop("Ipse Lorum");
            noop("Ipse Lorum");
            noop("Ipse Lorum");

            "<%1$s>",@_,"</%1$s>";
        }
__CODE__
    }
    print "Eval: ",time-$start;
}





print h1 h2 "closure";

print H1 H2 "eval";

    [download]

    output: 

    Closure: 0.0279860496520996
Eval: 0.343567132949829
<h1><h2>closure</h2></h1>
<H1><H2>eval</H2></H1>

    [download]

    One has to keep in mind that 15-20 years ago machines were factor 1000 slower, i.e. auto loading was relevant.

    Cheers Rolf
    (addicted to the Perl Programming Language and ☆☆☆☆ :)

    PS: Je suis Charlie!

    update

    fixed bug with no-ops.

    ¹) currying to be precise

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