While I still stand by the "more effort than it's worth" comment, I've been meaning to get more stuck into Devel::Declare lately, so I had a go, and this is what I came up with:

Data::Dumper::Declare

It gives you a Dumper function just like Data::Dumper (in fact, it uses Data::Dumper internally, so respects things like $Data::Dumper::Sortkeys), but figures out the variable names being dumped. So you can do this:

use Data::Dumper::Declare;

my $foo = 1;
my $bar = 'Hello World';
my @baz = qw(1 2 3);

print Dumper($foo, substr($bar, 0, 5), @baz);

[download]

... and you get:

$foo = 1;
$EXPR = 'Hello';
\@baz = [
  1,
  2,
  3
];

(Note that unlike Data::Dumper, you can't just eval the output. An assignment like \@bar = [...] is illegal.)

Data::Dumper::Declare isn't on CPAN yet. Do people think it useful enough to upload?

Update: just pushed a change which allows arrays and hashes to be dumped more nicely. e.g.

@baz = (
  1,
  2,
  3
);

Update 2: Data::Dumper::Declare is now on CPAN.

Update 3: Given this:

use Data::Dumper::Declare;

my @foo = qw(Hello World);

print Dumper(
    @foo,
    $foo[0],
    $foo[1],
    join('::', @foo),
);

[download]

The output is:

@foo = (
  'Hello',
  'World'
);
$foo[0] = 'Hello';
$foo[1] = 'World';
$EXPR = 'Hello::World';

Can anyone suggest something better than $EXPR in the output? It's certainly possible to output join('::', @foo) = 'Hello::World'; but I'm not especially fond of that. What do other people think?

perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'

In reply to Re^2: How to get variable name in trace message by tobyink
in thread How to get variable name in trace message by ChrisBeall

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