NAME
   B::LexInfo - Show information about subroutine lexical variables

SYNOPSIS
     use B::ShowLex ();
     my $lexi = B::ShowLex->new;

DESCRIPTION
   Perl stores lexical variable names and values inside a *padlist*
   within the subroutine. Certain lexicals will maintain certain
   attributes after the the variable "goes out of scope". For
   example, when a scalar is assigned a string value, this value
   remains after the variable has gone out of scope, but is
   overridden the next time it is assigned to. Lexical Arrays and
   Hashes will retain their storage space for the maximum number of
   entries stored at any given point in time.

   This module provides methods to record this information, which
   can be dumped out as-is or to compare two "snapshots". The
   information learned from these snapshots can be valuable in a
   number of ways.

METHODS
   new Create a new *B::LexInfo* object:

        my $lexi = B::LexInfo->new;

   cvlexinfo
       Create a padlist snapshot from a single subroutine:

         my $info = $lexi->cvlexinfo('Foo::bar');

   stash_cvlexinfo
       Create a list of padlist snapshots for each subroutine in
       the given package:

         my $info = $lexi->stash_cvlexinfo('Foo');

   dumper
       Return a reference to a stringified padlist snapshot:

         print ${ $lexi->dumper($info) }

   diff
       Compare two padlist snapshots and return the difference:

        my $before = $lexi->stash_cvlexinfo(__PACKAGE__);
        ... let some code run
        my $after = $lexi->stash_cvlexinfo(__PACKAGE__);

        my $diff = B::LexInfo->diff($before, $after);
        print $$diff;

       NOTE: This function relies on the *diff -u* command. You
       might need to configure $B::LexInfo::TmpDir and/or
       $B::LexInfo::DiffCmd to values other than the defaults in
       *LexInfo.pm*.

   cvrundiff
       Take a padlist snapshot of a subroutine, run the subroutine
       with the given arguments, take another snapshot and return a
       diff of the snapshots.

        my $diff = $lexi->cvrundiff('Foo::bar', "arg1", $arg2);
        print $$diff;

       Complete example:

        package Foo;
        use B::LexInfo ();

        sub bar {
            my($string) = @_;
        }

        my $lexi = B::LexInfo->new;
        my $diff = $lexi->cvrundiff('Foo::bar', "a string");
        print $$diff;

       Produces:

        --- /tmp/B_LexInfo_1848.before  Mon Jun 28 19:48:41 1999
        +++ /tmp/B_LexInfo_1848.after   Mon Jun 28 19:48:41 1999
        @@ -2,8 +2,10 @@
           {
             'Foo::bar' => {
               '$string' => {
        -        'TYPE' => 'NULL',
        -        'NULL' => '0x80efd58'
        +        'TYPE' => 'PV',
        +        'LEN' => 9,
        +        'PV' => 'a string',
        +        'CUR' => 8
               },
               '__SPECIAL__1' => {
                 'TYPE' => 'NULL',

SNAPSHOT INFO
   Snapshots are built using Perl structures and stringified using
   *Data::Dumper*. Hash key order is sorted and preserved if you
   you the *Tie::IxHash* module installed. Entry names are that of
   the variable itself or *__SPECIAL__$n* for entries that are used
   by Perl internally. The key/value pairs for each entry depends
   on the variable type and state. Docs on that to come, in the
   meantime, study: http://gisle.aas.no/perl/illguts/

SEE ALSO
   B(3), Apache::RegistryLexInfo(3), Devel::Peek(3)

AUTHOR
   Doug MacEachern

You are viewing proxied material from ftp.icm.edu.pl. The copyright of proxied material belongs to its original authors. Any comments or complaints in relation to proxied material should be directed to the original authors of the content concerned. Please see the disclaimer for more details.