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 out-
           put will not have the wrapping.  If you call the function with a single scalar
           (non-reference) 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*() func-
           tions 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 configuration 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 <>, based on "Data::Dumper" by
       Gurusamy Sarathy <>.

        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                                 2009-07-26                              Data::Dump(3)