Re: Pushing hash ref onto array ref

The "subtle difference" is that push-ing to an array reference was an experimental feature (~~added circa-5.10 IIRC~~ | added with Perl 5.14, removed as of Perl 5.24) that is now removed. For this reason, I would avoid it even if your particular version of Perl still supports it. (Update: If you intend ever to publish your module, I would absolutely avoid it!)

Win8 Strawberry 5.30.3.1 (64)  Sun 04/11/2021 19:15:44
C:\@Work\Perl\monks
>perl

use strict;
use warnings;

use Data::Dump qw(dd);

my %attrs = qw(foo 1  bar 2);;

my @products = ({
    'id'            => 0,
    'name'          => 'Test',
    'description'   => 'Some test data',
    'qty'           => 1,
    'price'         => 1000,
});
$attrs{'trolley'} = \@products;

my $self = \%attrs;

my $new_product = { qw(id 1  name Widget) };

push      $self->{'trolley'},   $new_product;
# push @{ $self->{'trolley'} }, $new_product;

dd \%attrs;

^Z
Experimental push on scalar is now forbidden at - line 22, near "$new_
+product;"
Execution of - aborted due to compilation errors.
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Give a man a fish: <%-{-{-{-<

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Re^2: Pushing hash ref onto array ref by Fletch (Bishop) on Apr 12, 2021 at 05:08 UTC
I'd use `push @{ $hash->{'key'} }, $new` out of habit personally, but if you've got a new enough perl (post 5.24.0 according to perlref; you can use back to 5.20 with a feature declaration) you could use the new postfix deref syntax `push $hash->{'key'}->@, $new` instead. Edit:* Clarified version requirement. The cake is a lie. The cake is a lie. The cake is a lie.	[reply] [d/l] [select]
Re^3: Pushing hash ref onto array ref by kcott (Archbishop) on Apr 12, 2021 at 10:58 UTC
I've been making a point of using "perlref: Postfix Dereference Syntax". It removes the need for nested braces and brackets (e.g. `%{$aref->[$i]}` and `@{$href->{$key}}`) which can be confusing. It also reads linearly; i.e. `ref->deref_to` (e.g. `$ref->%`) vs. `deref_to{ref}`. For very simple dereferencing, I often find myself using the older (original) syntax (e.g. `$$scalarref`). This is no doubt out of years of habit and muscle memory. I still think `$scalarref->$` is clearer and I try to remember to use that; it also adds consistency to my code. I also find "perlref: Postfix Reference Slicing" to be a lot clearer; especially when the initial reference is a complex variable itself. Of course, that all requires a sufficiently new version of Perl. For instance, I can't use that for $work where I'm constrained to `5.16`; for personal code, where I'm using the latest Perl (currently `5.32`) that's not an issue. — Ken	[reply] [d/l] [select]
Re^4: Pushing hash ref onto array ref by Bod (Parson) on Apr 12, 2021 at 11:51 UTC
Of course, that all requires a sufficiently new version of Perl. For instance, I can't use that for $work where I'm constrained to 5.16; for personal code, where I'm using the latest Perl (currently 5.32) that's not an issue. It didn't occur to me that they both worked because I am using an old version of Perl v5.16.3 on the server. Because I hadn't made the connection with versioning, I didn't think to try it locally on v5.32.1...	[reply]
Re^2: Pushing hash ref onto array ref by Bod (Parson) on Apr 12, 2021 at 11:54 UTC
(Update: If you intend ever to publish your module, I would absolutely avoid it!) Yes...this module is probably of sufficient utility to be heading for CPAN so expect a few more questions about it and an RFC when I get that far...	[reply]