Re^2: Using Data::Printer from the Perl debugger

[ibm1620]

Using pure guesswork, I made one change to DB::Pluggable::Plugin::DataPrinter.pm:

sub initialize {
    no warnings 'once';
#    $DB::alias{p} = 's/^/use Data::Printer; /; eval $cmd';
    $DB::alias{p} = 's/^/use Data::Printer; /';
}

Now the p command prints its argument only once.

I inserted print $cmd; before eval $cmd, entered p $my_var in the debugger, and it printed "p $my_var". Apparently the eval was unnecessary.

FWIW.

[LanX]

You are mangling internal p command and aliases, here are dragons.

If I were you I'd stick with px

Otherwise you need to look into the code of perl5db.pl

[ibm1620]

You are mangling internal p command and aliases

But isn't that exactly what the author(s) of DB::Pluggable::Plugin::DataPrinter.pm are doing? Or are you saying that approach isn't advisable?

My only objection to px is I have to explicitly en-reference non-scalars, and I've become used to using the p command without doing that. Not a big deal.... :)

[LanX]

> of DB::Pluggable::Plugin::DataPrinter.pm are doing?

I don't know ... I was expecting them to monkey patch the sub for the p cmd. That's why $cmd is set, btw.

> en-reference non-scalars

you mean %h -> \%h ... IMHO this could be automatically done with a sub prototype ( like (\[%@$*]) )

> p command without doing that

p is for printing x for dumping,

I'd rather patch x

  DB<1> $x=[1,2,3]

  DB<2> p $x
ARRAY(0x32c8908)
  DB<3> x $x
0  ARRAY(0x32c8908)
   0  1
   1  2
   2  3
  DB<4>

FWIW you can test aliasing interactively with =

 DB<4> h p
p expr        Same as "print {DB::OUT} expr" in current package.
perldoc manpage    Runs the external doc viewer perldoc command on the
        named Perl manpage, or on perldoc itself if omitted.
        Set $DB::doccmd to change viewer.

  DB<5> h x
x expr        Evals expression in list context, dumps the result.
  DB<6> h =
= [alias value]    Define a command alias, or list current aliases.
  DB<7>