Data::Dump

Data::Dump(3)	     User Contributed Perl Documentation	Data::Dump(3)



NAME
       Data::Dump - Pretty printing of data structures

SYNOPSIS
	use Data::Dump qw(dump ddx);

	$str = dump(@list);
	@copy_of_list = eval $str;

	# or use it for easy debug printout
	ddx localtime;

DESCRIPTION
       This module provide functions that takes a list of values as their
       argument and produces a string as its result.  The string contains
       Perl code that, when "eval"ed, produces a deep copy of the original
       arguments.

       The main feature of the module is that it strives to produce output
       that is easy to read.  Example:

	   @a = (1, [2, 3], {4 => 5});
	   dump(@a);

       Produces:

	   (1, [2, 3], { 4 => 5 })

       If you dump just a little data, it is output on a single line. If you
       dump data that is more complex or there is a lot of it, line breaks
       are automatically added to keep it easy to read.

       The following functions are provided (only the dd* functions are
       exported by default):

       dump( ... )
       pp( ... )
	   Returns a string containing a Perl expression.  If you pass this
	   string to Perl’s built-in eval() function it should return a copy
	   of the arguments you passed to dump().

	   If you call the function with multiple arguments then the output
	   will be wrapped in parenthesis "( ..., ... )".  If you call the
	   function with a single argument the output will not have the wrap-
	   ping.  If you call the function with a single scalar (non-refer-
	   ence) argument it will just return the scalar quoted if needed,
	   but never break it into multiple lines.  If you pass multiple
	   arguments or references to arrays of hashes then the return value
	   might contain line breaks to format it for easier reading.  The
	   returned string will never be "\n" terminated, even if contains
	   multiple lines.  This allows code like this to place the semicolon
	   in the expected place:

	      print ’$obj = ’, dump($obj), ";\n";

	   If dump() is called in void context, then the dump is printed on
	   STDERR and then "\n" terminated.  You might find this useful for
	   quick debug printouts, but the dd*() functions might be better
	   alternatives for this.

	   There is no difference between dump() and pp(), except that dump()
	   shares its name with a not-so-useful perl builtin.  Because of
	   this some might want to avoid using that name.

       quote( $string )
	   Returns a quoted version of the provided string.

	   It differs from "dump($string)" in that it will quote even numbers
	   and not try to come up with clever expressions that might shorten
	   the output.

       dd( ... )
       ddx( ... )
	   These functions will call dump() on their argument and print the
	   result to STDOUT (actually, it’s the currently selected output
	   handle, but STDOUT is the default for that).

	   The difference between them is only that ddx() will prefix the
	   lines it prints with "# " and mark the first line with the file
	   and line number where it was called.	 This is meant to be useful
	   for debug printouts of state within programs.

LIMITATIONS
       Code references will be displayed as simply ’sub { "???" }’ when
       dumped. Thus, "eval"ing them will not reproduce the original routine.

       If you forget to explicitly import the "dump" function, your code will
       core dump. That’s because you just called the builtin "dump" function
       by accident, which intentionally dumps core.  Because of this you can
       also import the same function as "pp", mnemonic for "pretty-print".

HISTORY
       The "Data::Dump" module grew out of frustration with Sarathy’s in-
       most-cases-excellent "Data::Dumper".  Basic ideas and some code are
       shared with Sarathy’s module.

       The "Data::Dump" module provides a much simpler interface than
       "Data::Dumper".	No OO interface is available and there are no config-
       uration options to worry about (yet :-).	 The other benefit is that
       the dump produced does not try to set any variables.  It only returns
       what is needed to produce a copy of the arguments.  This means that
       "dump("foo")" simply returns "foo", and "dump(1..5)" simply returns
       "(1, 2, 3, 4, 5)".

SEE ALSO
       Data::Dumper, Storable

AUTHORS
       The "Data::Dump" module is written by Gisle Aas <gisle@aas.no>, based
       on "Data::Dumper" by Gurusamy Sarathy <gsar@umich.edu>.

	Copyright 1998-2000,2003-2004,2008 Gisle Aas.
	Copyright 1996-1998 Gurusamy Sarathy.

       This library is free software; you can redistribute it and/or modify
       it under the same terms as Perl itself.



perl v5.8.8			  2009-01-12			Data::Dump(3)