Hi
I never liked the usage of the CODEHASHREF in Benchmark.
Often people start writing things like
sub name1 {
...
}
sub name2 {
...
}
cmpthese (
-5,
{
'name1' => \&name1,
'name2' => \&name2,
}
)
which isn't very DRY and makes experimenting with optimizations really cumbersome! (I hate it, every new function name has to be repeated 3 times in different locations...)
see also Re: Best method to diff very large array efficiently for another examle.
My idea is to put all subs into a dedicated package (defaultname "CMP" or so) and to automatically filter necessary name and coderefs.
{
package CMP;
sub name1 {
...
}
sub name2 {
...
}
}
cmpthese (-5, pckg_subs("CMP") )
ATM I'm using a function pckg_subs() for this, not sure if it makes sense to extend the interface of cmpthese and timethese to directly accept a stash-ref like \%CMP::. ¹
Following a proof on concept, request for comments.
use strict;
use warnings;
use Benchmark qw/cmpthese/;
use Data::Dump qw/pp/;
{
package CMP;
my @arr_1 = map {rand 1e6} 8000;
my @arr_2 = map {rand 1e6} 6000;
sub hash_values_diff {
my %diff3;
@diff3{@arr_1} = @arr_1;
delete @diff3{@arr_2};
values %diff3 ;
}
sub hash_key_diff {
my %diff3;
@diff3{@arr_1} = ();
delete @diff3{@arr_2};
keys %diff3 ;
}
sub using_vec {
my $vec = '';
vec( $vec, $_, 1 ) = 1 for @arr_2;
grep !vec( $vec, $_, 1 ), @arr_1;
}
sub hash_grep {
my %arr_2_hash;
undef @arr_2_hash{@arr_2};
grep !exists $arr_2_hash{$_}, @arr_1;
}
}
cmpthese(-5, pckg_subs() );
sub pckg_subs {
my $pckg_name= shift // "CMP";
my $stash = do {
no strict 'refs';
\ %{ "${pckg_name}::" };
};
# filter all subs from package
my $codehashref;
while (my ($name,$glob)= each %$stash) {
if ( my $cref = *{$glob}{CODE} ) {
print "$name:\t$glob\n";
$codehashref->{$name}=$cref;
}
}
return $codehashref;
}
OUTPUT
/usr/bin/perl -w /tmp/diff.pl
hash_grep: *CMP::hash_grep
hash_key_diff: *CMP::hash_key_diff
hash_values_diff: *CMP::hash_values_diff
using_vec: *CMP::using_vec
Rate using_vec hash_values_diff hash_key_diff
+ hash_grep
using_vec 22269/s -- -85% -90%
+ -91%
hash_values_diff 148869/s 568% -- -31%
+ -40%
hash_key_diff 215078/s 866% 44% --
+ -13%
hash_grep 247455/s 1011% 66% 15%
+ --
The idea code be extended with sub-attribute ':compare' or ':nocompare' to additionally mark functions which are supposed to be compared or not.
Cheers Rolf
( addicted to the Perl Programming Language)
update
¹) is it possible to tell if a hashref belongs to a stash?
... well at least I could parse %main or pass the packagename directly =)
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