Shell::Perl::Dumper - Dumpers for Shell::Perl

Shell-Perl documentation Contained in the Shell-Perl distribution.

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NAME

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Shell::Perl::Dumper - Dumpers for Shell::Perl

SYNOPSYS

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    use Shell::Perl::Dumper;
    $dumper = Shell::Perl::Dumper::Plain->new;
    print $dumper->dump_scalar($scalar);
    print $dumper->dump_list(@list);

DESCRIPTION

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In pirl, the result of the evaluation is transformed into a string to be printed. As this result may be a pretty complex data structure, the shell provides a hook for you to pretty-print these answers just the way you want.

By default, pirl will try to convert the results via Data::Dump. That means the output will be Perl code that may be run to get the data structure again. Alternatively, the shell may use Data::Dumper or Data::Dump::Streamer with almost the same result with respect to the representation as Perl code. (But the output of the modules differ enough for sufficiently complex data.)

Other options are to set the output to produce YAML or a plain simple-minded solution which basically turns the result to string via simple interpolation.

All of these are implemented via dumper objects. Dumpers are meant to be used like that:

   $dumper = Some::Dumper::Class->new; # build a dumper

   $s = $dumper->dump_scalar($scalar); # from scalar to string

   $s = $dumper->dump_list(@list); # from list to string

METHODS

The following methods compose the expected API of a dumper, as used by Shell::Perl.

new
    $dumper = $class->new(@args);

Constructs a dumper.

dump_scalar
    $s = $dumper->dump_scalar($scalar);

Turns a scalar into a string representation.

dump_list
    $s = $dumper->dump_list(@list);

Turns a list into a string representation.

is_available
    $ok = $class->is_available

This is an optional class method. If it exists, it means that the class has external dependencies (like Shell::Perl::Data::Dump depends on Data::Dump) and whether these may be loaded when needed. If they can, this method returns true. Otherwise, returning false means that a dumper instance of this class probably cannot work. This is typically because the dependency is not installed or cannot be loaded due to an installation problem.

This is the algorithm used by Shell::Perl XXX XXX XXX

    1.

THE STANDARD DUMPERS

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Shell::Perl provides four standard dumpers:

    * Shell::Perl::Data::Dump
    * Shell::Perl::Data::Dumper
    * Shell::Perl::Data::Dump::Streamer
    * Shell::Perl::Dumper::YAML
    * Shell::Perl::Dumper::Plain

which corresponds to the four options of the command :set out : "D", "DD", "DDS", "Y", and "P" respectively.

Data::Dump

The package Shell::Perl::Data::Dump implements a dumper which uses Data::Dump to turn Perl variables into a string representation.

It is used like this:

    use Shell::Perl::Dumper;

    if (!Shell::Perl::Data::Dump->is_available) {
        die "the dumper cannot be loaded correctly"
    }
    $dumper = Shell::Perl::Data::Dump->new;
    print $dumper->dump_scalar($scalar);
    print $dumper->dump_list(@list);

Examples of its output:

    pirl > :set out D

    pirl > { a => 3 } #scalar
    { a => 3 }

    pirl > (1, 2, "a") #list
    (1, 2, "a")

Data::Dumper

The package Shell::Perl::Data::Dumper implements a dumper which uses Data::Dumper to turn Perl variables into a string representation.

It is used like this:

    use Shell::Perl::Dumper;

    if (!Shell::Perl::Data::Dumper->is_available) {
        die "the dumper cannot be loaded correctly"
    }
    $dumper = Shell::Perl::Data::Dumper->new;
    print $dumper->dump_scalar($scalar);
    print $dumper->dump_list(@list);

Examples of its output:

    pirl > :set out DD

    pirl > { a => 3 } #scalar
    @var = (
             {
               'a' => 3
             }
           );

    pirl > (1, 2, "a") #list
    @var = (
             1,
             2,
             'a'
           );

YAML

The package Shell::Perl::Dumper::YAML implements a dumper which uses YAML::Syck or YAML to turn Perl variables into a string representation.

It is used like this:

    use Shell::Perl::Dumper;

    if (!Shell::Perl::Dumper::YAML->is_available) {
        die "the dumper cannot be loaded correctly"
    }
    $dumper = Shell::Perl::Dumper::YAML->new;
    print $dumper->dump_scalar($scalar);
    print $dumper->dump_list(@list);

Examples of its output:

    pirl > :set out Y

    pirl @> { a => 3 } #scalar
    ---
    a: 3

    pirl @> (1, 2, "a") #list
    --- 1
    --- 2
    --- a

When loading, YAML::Syck is preferred to YAML. If it is not avaiable, the YAML module is the second option.

Data::Dump::Streamer

The documentation is yet to be written.

Plain Dumper

The package Shell::Perl::Dumper::Plain implements a dumper which uses string interpolation to turn Perl variables into strings.

It is used like this:

    use Shell::Perl::Dumper;

    $dumper = Shell::Perl::Dumper::Plain->new;
    print $dumper->dump_scalar($scalar);
    print $dumper->dump_list(@list);

Examples of its output:

    pirl > :set out P

    pirl > { a => 3 } #scalar
    HASH(0x1094d2c0)

    pirl > (1, 2, "a") #list
    1       2       a

SEE ALSO

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    Shell::Perl

BUGS

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Please report bugs via CPAN RT http://rt.cpan.org/NoAuth/Bugs.html?Dist=Shell-Perl or mailto://bugs-Shell-Perl@rt.cpan.org.

AUTHORS

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Adriano R. Ferreira, <ferreira@cpan.org>

Caio Marcelo, <cmarcelo@gmail.com>

COPYRIGHT AND LICENSE

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Copyright (C) 2007–2011 by Adriano R. Ferreira

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

Shell-Perl documentation Contained in the Shell-Perl distribution. 
package Shell::Perl::Dumper;

use 5;
use strict;
use warnings;

# $Id$

our $VERSION = '0.0019';

use base qw(Class::Accessor); # to get a new() for free

package Shell::Perl::Dumper::Plain;

our @ISA = qw(Shell::Perl::Dumper); # to get a new() for free

sub is_available {
    return 1; # always available - no dependency but Perl
}

sub dump_scalar {
    shift;
    return "$_[0]" . "\n";
}

sub dump_list {
    shift;
    local $" = "\t";
    return "@_" . "\n";
}

package Shell::Perl::Data::Dump;

our @ISA = qw(Shell::Perl::Dumper); # to get a new() for free

# XXX make a Data::Dump object an instance variable

sub _dump_code_filter {
    my ($ctx, $object_ref) = @_;
    return undef unless $ctx->is_code;

    require B::Deparse;
    my $code = 'sub ' . (B::Deparse->new)->coderef2text($object_ref);
    return { dump => $code };
}

sub is_available {
    return eval { require Data::Dump::Filtered; 1 };
}

sub dump_scalar {
    shift;
    require Data::Dump::Filtered;
    return Data::Dump::Filtered::dump_filtered(shift, \&_dump_code_filter) . "\n";
}

sub dump_list {
    shift;
    require Data::Dump::Filtered;
    return Data::Dump::Filtered::dump_filtered(@_, \&_dump_code_filter) . "\n";
}

package Shell::Perl::Data::Dumper;

our @ISA = qw(Shell::Perl::Dumper);

# XXX make a Data::Dumper object an instance variable
#     but OO Data::Dumper is very annoying

sub is_available {
    return eval { require Data::Dumper; 1 };
}

sub dump_scalar {
    shift;
    require Data::Dumper; 
    local $Data::Dumper::Deparse = 1;
    return Data::Dumper->Dump([shift], [qw($var)]);
}

sub dump_list {
    #goto &dump_scalar if @_==2; # fallback to dump_scalar if only one
    shift;
    require Data::Dumper; 
    local $Data::Dumper::Deparse = 1;
    return Data::Dumper->Dump([[@_]], [qw(*var)]);
}

package Shell::Perl::Dumper::YAML;

our @ISA = qw(Shell::Perl::Dumper);

sub _require_one_of {
    my @modules = @_;
    for (@modules) {
        my $ret = eval "require $_; 1";
        warn "pirl: $_ loaded ok\n" if $ret; # XXX
        return $_ if $ret;
    }
    return undef
}

our $YAML_PACKAGE;

sub is_available {
    #return eval { require YAML; 1 };
    $YAML_PACKAGE = _require_one_of(qw(YAML::Syck YAML));
    if ($YAML_PACKAGE) {
        $YAML_PACKAGE->import(qw(Dump));
        do { no strict 'refs'; ${ $YAML_PACKAGE . '::DumpCode' } = 1 };
        return 1
    } else {
        return undef;
    }

}

sub dump_scalar {
    shift;
    #require YAML; # done by &is_available
    return Dump(shift);
}

sub dump_list { # XXX
    shift;
    #require YAML; # done by &is_available
    return Dump(@_);
}

package Shell::Perl::Data::Dump::Streamer;

our @ISA = qw(Shell::Perl::Dumper);

sub is_available {
    return eval { require Data::Dump::Streamer; 1 };
}

sub dump_scalar {
    shift;
    require Data::Dump::Streamer; 
    return Data::Dump::Streamer::Dump(shift)->Names('$var')->Out;
}

sub dump_list {
    #goto &dump_scalar if @_==2; # fallback to dump_scalar if only one
    shift;
    require Data::Dump::Streamer; 
    return Data::Dump::Streamer::Dump([@_])->Names('*var')->Out;
}

1;

# svn:keywords Id
# svn:eol-style LF

__END__