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| PadWalker v2.5    - Robin Houston
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NAME
       PadWalker - play with other peoples' lexical variables

SYNOPSIS
	 use PadWalker qw(peek_my peek_our peek_sub closed_over);
	 ...

DESCRIPTION
       PadWalker is a module which allows you to inspect (and even change!)
       lexical variables in any subroutine which called you. It will only show
       those variables which are in scope at the point of the call.

       PadWalker is particularly useful for debugging. It's even used by
       Perl's built-in debugger. (It can also be used for evil, of course.)

       I wouldn't recommend using PadWalker directly in production code, but
       it's your call. Some of the modules that use PadWalker internally are
       certainly safe for and useful in production.

       peek_my LEVEL
       peek_our LEVEL
	   The LEVEL argument is interpreted just like the argument to
	   "caller".  So peek_my(0) returns a reference to a hash of all the
	   "my" variables that are currently in scope; peek_my(1) returns a
	   reference to a hash of all the "my" variables that are in scope at
	   the point where the current sub was called, and so on.

	   "peek_our" works in the same way, except that it lists the "our"
	   variables rather than the "my" variables.

	   The hash associates each variable name with a reference to its
	   value. The variable names include the sigil, so the variable $x is
	   represented by the string '$x'.

	   For example:

	     my $x = 12;
	     my $h = peek_my (0);
	     ${$h->{'$x'}}++;

	     print $x;	# prints 13

	   Or a more complex example:

	     sub increment_my_x {
	       my $h = peek_my (1);
	       ${$h->{'$x'}}++;
	     }

	     my $x=5;
	     increment_my_x;
	     print $x;	# prints 6

       peek_sub SUB
	   The "peek_sub" routine takes a coderef as its argument, and returns
	   a hash of the "my" variables used in that sub. The values will usu-
	   ally be undefined unless the sub is in use (i.e. in the call-chain)
	   at the time. On the other hand:

	     my $x = "Hello!";
	     my $r = peek_sub(sub {$x})->{'$x'};
	     print "$$r\n";	   # prints 'Hello!'

	   If the sub defines several "my" variables with the same name,
	   you'll get the last one. I don't know of any use for "peek_sub"
	   that isn't broken as a result of this, and it will probably be dep-
	   recated in a future version in favour of some alternative inter-
	   face.

       closed_over SUB
	   "closed_over" is similar to "peek_sub", except that it only lists
	   the "my" variables which are used in the subroutine but defined
	   outside: in other words, the variables which it closes over. This
	   does have reasonable uses: see Data::Dump::Streamer, for example (a
	   future version of which may in fact use "closed_over").

       set_closed_over SUB, HASH_REF