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Data-Pretty-v0.1.9
River stage one • 1 direct dependent • 1 total dependent
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/ Data::Pretty

NAME

Data::Pretty - Data Dump Beautifier

SYNOPSIS

    use Data::Pretty qw( dump );
    $str = dump(@list);
    @copy_of_list = eval $str;

    # or use it for easy debug printout
    use Data::Pretty; dd localtime;

    use Data::Pretty qw( dump literal );
    my $users = [qw( John Peter )];
    my $ref = { name => literal( '$users->[0]' ) };
    say dump( $ref ); # { name => $users->[0] }

VERSION

    v0.1.9

DESCRIPTION

This is a fork from Data::Dump and a drop-in replacement with the aim at providing the following improvements:

  • Avoid long indentation matching the length of a property

    For example, Data::Dump would produce

        {
        query => { term => { user => "kimchy" } },
        sort  => [
                     { post_date => { order => "asc" } },
                     "user",
                     { name => "desc" },
                     { age => "desc" },
                     "_score",
                 ],
    }

    whereas, Data::Pretty would make it more crisp:

        {
        query => {
            term => { user => "kimchy" },
        },
        sort => [
            {
                post_date => { order => "asc" },
            },
            "user",
            { name => "desc" },
            { age => "desc" },
            "_score",
        ],
    }

  • Break down structure for clarity when necessary

    For example, the following structure with Data::Dump:

        { from => 0, query => { term => { user => "kimchy" } }, size => 10 }

    would become, under Data::Pretty:

        {
        from => 0,
        query => {
            term => { user => "kimchy" },
        },
        size => 10,
    }

  • Prevent UTF-8 characters from being encoded in hexadecimal.

    Data::Dump would encode ジャック as \x{30B8}\x{30E3}\x{30C3}\x{30AF}, which although correct, is not human readable.

    However, not encoding in hexadecimal UTF-8 strings means that if you print it out, you will need to set the "binmode" in perlfunc to utf-8. You can also use open when printing on the STDOUT or STDERR:

        use open ':std' => 'utf8';

    You can disable this by setting $Data::Pretty::SHOW_UTF8 to false.

  • Quoting hash keys

    With Data::Dump, whenever at least 1 hash key has non alphanumeric characters, it is rightfully surrounded by double quotes, but unfortunately so are all the other hash keys who do not need surrounding double quotes.

    Thus, for example, Data::Dump would produce:

        {
        query => {
            term => { user => "kimchy" },
        },
        sort => [
            {
                _geo_distance => {
                    "distance_type" => "sloppy_arc",
                    "mode" => "min",
                    "order" => "asc",
                    "pin.location" => [-70, 40],
                    "unit" => "km",
                },
            },
        ],
    }

    whereas, Data::Pretty would rather produce:

        {
        query => {
            term => { user => "kimchy" },
        },
        sort => [
            {
                _geo_distance => {
                    distance_type => "sloppy_arc",
                    mode => "min",
                    order => "asc",
                    "pin.location" => [-70, 40],
                    unit => "km",
                },
            },
        ],
    }

  • Specify literal string values

    You can set a literal string value in your data by passing it to the literal method. Normally, a string is quoted and its characters within escaped as they need be. If you use literal, the value will be used as-is in the dump.

    For example, consider the following 2 examples, one without and the other with using literal

        use Data::Dump qw( dump literal );
    my $ref = 
    {
        name => '$users->[0]',
        values => '["some","thing"]',
    };
    say dump( $ref ); # { name => "\$users->[0]", values => "[\"some\",\"thing\"]" }

    my $ref = 
    {
        name => literal( '$users->[0]' ),
        values => literal( '["some","thing"]' ),
    };
    say dump( $ref ); # { name => $users->[0], values => ["some","thing"] }

The rest of this documentation is identical to the original Data::Dump.

This module provide a few functions that traverse their argument and produces a string as its result. The string contains Perl code that, when evaled, 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 and ddx functions are exported by default):

FUNCTIONS

dd( ... )

ddx( ... )

These functions will call dump on their argument and print the result to STDOUT (actually, it is 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.

dump

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 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 Ldd|/dd> and "ddx" in ddx 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.

dumpf( ..., \&filter )

Short hand for calling the dump_filtered function of Data::Pretty::Filtered.

This works like dump, but the last argument should be a filter callback function. As objects are visited the filter callback is invoked and it can modify how the objects are dumped.

literal

This takes a value and marks it as a literal value that will be used as-is in the resulting dump.

For example, consider the following 2 examples, one without and the other with using literal

    use Data::Dump qw( dump literal );
    my $ref = 
    {
        name => '$users->[0]',
        values => '["some","thing"]',
    };
    say dump( $ref ); # { name => "\$users->[0]", values => "[\"some\",\"thing\"]" }

    my $ref = 
    {
        name => literal( '$users->[0]' ),
        values => literal( '["some","thing"]' ),
    };
    say dump( $ref ); # { name => $users->[0], values => ["some","thing"] }

pp

Same as "dump"

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. If a non-scalar argument is provided then it's just stringified instead of traversed.

CONFIGURATION

There are a few global variables that can be set to modify the output generated by the dump functions. It's wise to localize the setting of these.

$Data::Pretty::CODE_DEPARSE

When set to true, which is the default, this will use B::Deparse, if available, to reproduce the perl code of the anonymous subroutines found. Note that due to perl's internal way of working, the code reproduced might not be exactly the same as the original.

$Data::Pretty::INDENT

This holds the string that's used for indenting multiline data structures. It's default value is " " (four spaces). Set it to "" to suppress indentation. Setting it to "| " makes for nice visuals even if the dump output then fails to be valid Perl.

$Data::Pretty::SHOW_UTF8

When set to true (default), this will show the UTF-8 texts as is and when set to a false value, this will revert to the Data::Dump original behaviour of showing the text with its characters encoded in hexadecimal. For example, a string like

    ジャック

would be encoded in Data::Dump as:

    \x{30B8}\x{30E3}\x{30C3}\x{30AF}

$Data::Pretty::TRY_BASE64

How long must a binary string be before we try to use the base64 encoding for the dump output. The default is 50. Set it to 0 to disable base64 dumps.

LIMITATIONS

1. Core reference

Code references will be dumped as sub { ... }. Thus, evaling them will not reproduce the original routine. The ...-operator used will also require perl-5.12 or better to be evaled.

2. Importing dump

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".

SEE ALSO

Data::Pretty::Filtered, Data::Pretty::FilterContext

Data::Dump, Data::Dumper

CREDITS

Credits to Gisle Aas for the original Data::Dump version and to Breno G. de Oliveira for maintaining it.

COPYRIGHT & LICENSE

Copyright(c) 2023 DEGUEST Pte. Ltd.

All rights reserved

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