Is there an equivalent to the perl debugger 'x' in pdl2 (or Devel::REPL)?

问题

I am using pdl2 (the PDL shell) also as a my default Perl interactive shell (it loads all the nice plugins for Devel::REPL). But I am missing the x dumper-printing alias. p is nice for piddles but it does not work for a normal array ref or hash ref. I have loaded Data::Dumper but it lacks an easy way of controlling depth and I like the way you can quickly set depth limits with x, e.g. x 2 $deep_datastruct for complex data structures. But with Data::Dumper the process is more cumbersome:

pdl> say $c
HASH(0x53b0b60)

pdl> p $c
HASH(0x12b14018)

pdl> use Data::Dumper

pdl> p Dumper $c
$VAR1 = {
          'c' => {
                   'c' => 3,
                   'a' => 1,
                   'b' => {
                            'c' => '3',
                            'a' => '1',
                            'b' => '2'
                          }
                 },
          'a' => 1,
          'b' => 4
        };
pdl>  $Data::Dumper::Maxdepth = 1;
pdl> p Dumper $c
$VAR1 = {
          'c' => 'HASH(0x97fba70)',
          'a' => 1,
          'b' => 4
        };

In the Perl debugger you can achieve the same thing with x 1 $c directly. Does pdl2 have something similar and so concise?

[update] And related with this question: does pdl2 or Devel::REPL have convenience functions like the Perl debugger commands m or y? Or should one create a module with PadWalker and export them? I would like to use a real REPL instead of the Perl debugger as an interactive shell, but still the Perl debugger has some important things that I don't know how to do with Devel::REPL or pdl2.

For example to see all variables (pdl2 only show piddles):

pdl> help vars
PDL variables in package main::

Name         Type   Dimension       Flow  State          Mem
----------------------------------------------------------------
no PDL objects in package main::

By the way, does someone know a Devel::REPL plugin for listing all the variables in use (like y in the debugger, but only the names, not the values) and then have a x-like to dump the wanted one?

回答1:

It looks like Devel::REPL provides an straightforward alternative for your first question. Create a file called '.perldlrc' in your home directory that looks like:

use Data::Dumper;

sub x { 
  my $depth = shift;
  $Data::Dumper::Maxdepth = $depth;
  print Data::Dumper->Dump([@_])
}

Unfortunately, you need a comma as in:

pdl> x 1, $c

It looks like you can implement the other commands with this same control-file approach. I don't see a way to get rid the need for the comma, although I don't think there's any reason Devel::REPL cannot be made to recognize and parse these kinds of commands.

回答2:

The Devel::REPL shell re.pl already dumps the value of the last expression by default:

[foo@host]$ re.pl
$ { a => 23, b => 34}
$HASH1 = {
           a => 23,
           b => 34
         };

$ 

来源：https://stackoverflow.com/questions/3898558/is-there-an-equivalent-to-the-perl-debugger-x-in-pdl2-or-develrepl