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=head1 Template

As you can see in the synopsis, based on your template, the arguments
provided will be validated.

The template can take a different set of rules per key that is used.

The following rules are available:

=over 4

=item default

This is the default value if none was provided by the user.
This is also the type C<strict_type> will look at when checking type
integrity (see below).

=item required

A boolean flag that indicates if this argument was a required
argument. If marked as required and not provided, check() will fail.

=item strict_type

This does a C<ref()> check on the argument provided. The C<ref> of the
argument must be the same as the C<ref> of the default value for this
check to pass.

This is very useful if you insist on taking an array reference as
argument for example.

=item defined

If this template key is true, enforces that if this key is provided by
user input, its value is C<defined>. This just means that the user is
not allowed to pass C<undef> as a value for this key and is equivalent
to:
    allow => sub { defined $_[0] && OTHER TESTS }

=item no_override

This allows you to specify C<constants> in your template. ie, they
keys that are not allowed to be altered by the user. It pretty much
allows you to keep all your C<configurable> data in one place; the
C<Params::Check> template.

=item store

This allows you to pass a reference to a scalar, in which the data
will be stored:

    my $x;
    my $args = check(foo => { default => 1, store => \$x }, $input);

This is basically shorthand for saying:

    my $args = check( { foo => { default => 1 }, $input );
    my $x    = $args->{foo};

You can alter the global variable $Params::Check::NO_DUPLICATES to
control whether the C<store>'d key will still be present in your
result set. See the L<Global Variables> section below.

=item allow

A set of criteria used to validate a particular piece of data if it
has to adhere to particular rules.

See the C<allow()> function for details.

=back

=head1 Functions

=head2 check( \%tmpl, \%args, [$verbose] );

This function is not exported by default, so you'll have to ask for it
via:

    use Params::Check qw[check];

or use its fully qualified name instead.

C<check> takes a list of arguments, as follows:

=over 4

=item Template

This is a hashreference which contains a template as explained in the
C<SYNOPSIS> and C<Template> section.

=item Arguments

This is a reference to a hash of named arguments which need checking.

=item Verbose

A boolean to indicate whether C<check> should be verbose and warn
about what went wrong in a check or not.

You can enable this program wide by setting the package variable
C<$Params::Check::VERBOSE> to a true value. For details, see the
section on C<Global Variables> below.

=back

C<check> will return when it fails, or a hashref with lowercase
keys of parsed arguments when it succeeds.

So a typical call to check would look like this:

    my $parsed = check( \%template, \%arguments, $VERBOSE )
                    or warn q[Arguments could not be parsed!];

A lot of the behaviour of C<check()> can be altered by setting
package variables. See the section on C<Global Variables> for details
on this.

=cut

inc/inc_Params-Check/Params/Check.pm  view on Meta::CPAN

    }

    ### we got here, no failures ###
    return 1;
}

### helper functions ###

sub _safe_eq {
    ### only do a straight 'eq' if they're both defined ###
    return defined($_[0]) && defined($_[1])
                ? $_[0] eq $_[1]
                : defined($_[0]) eq defined($_[1]);
}

sub _who_was_it {
    my $level = $_[0] || 0;

    return (caller(2 + $CALLER_DEPTH + $level))[3] || 'ANON'
}

=head2 last_error()

Returns a string containing all warnings and errors reported during
the last time C<check> was called.

This is useful if you want to report then some other way than
C<carp>'ing when the verbose flag is on.

It is exported upon request.

=cut

{   $_ERROR_STRING = '';

    sub _store_error {
        my($err, $verbose, $offset) = @_[0..2];
        $verbose ||= 0;
        $offset  ||= 0;
        my $level   = 1 + $offset;

        local $Carp::CarpLevel = $level;

        carp $err if $verbose;

        $_ERROR_STRING .= $err . "\n";
    }

    sub _clear_error {
        $_ERROR_STRING = '';
    }

    sub last_error { $_ERROR_STRING }
}

1;

=head1 Global Variables

The behaviour of Params::Check can be altered by changing the
following global variables:

=head2 $Params::Check::VERBOSE

This controls whether Params::Check will issue warnings and
explanations as to why certain things may have failed.
If you set it to 0, Params::Check will not output any warnings.

The default is 1 when L<warnings> are enabled, 0 otherwise;

=head2 $Params::Check::STRICT_TYPE

This works like the C<strict_type> option you can pass to C<check>,
which will turn on C<strict_type> globally for all calls to C<check>.

The default is 0;

=head2 $Params::Check::ALLOW_UNKNOWN

If you set this flag, unknown options will still be present in the
return value, rather than filtered out. This is useful if your
subroutine is only interested in a few arguments, and wants to pass
the rest on blindly to perhaps another subroutine.

The default is 0;

=head2 $Params::Check::STRIP_LEADING_DASHES

If you set this flag, all keys passed in the following manner:

    function( -key => 'val' );

will have their leading dashes stripped.

=head2 $Params::Check::NO_DUPLICATES

If set to true, all keys in the template that are marked as to be
stored in a scalar, will also be removed from the result set.

Default is false, meaning that when you use C<store> as a template
key, C<check> will put it both in the scalar you supplied, as well as
in the hashref it returns.

=head2 $Params::Check::PRESERVE_CASE

If set to true, L<Params::Check> will no longer convert all keys from
the user input to lowercase, but instead expect them to be in the
case the template provided. This is useful when you want to use
similar keys with different casing in your templates.

Understand that this removes the case-insensitivity feature of this
module.

Default is 0;

=head2 $Params::Check::ONLY_ALLOW_DEFINED

If set to true, L<Params::Check> will require all values passed to be
C<defined>. If you wish to enable this on a 'per key' basis, use the
template option C<defined> instead.

Default is 0;

=head2 $Params::Check::SANITY_CHECK_TEMPLATE

If set to true, L<Params::Check> will sanity check templates, validating
for errors and unknown keys. Although very useful for debugging, this
can be somewhat slow in hot-code and large loops.

To disable this check, set this variable to C<false>.

Default is 1;

=head2 $Params::Check::WARNINGS_FATAL

If set to true, L<Params::Check> will C<croak> when an error during
template validation occurs, rather than return C<false>.

Default is 0;

=head2 $Params::Check::CALLER_DEPTH

This global modifies the argument given to C<caller()> by
C<Params::Check::check()> and is useful if you have a custom wrapper
function around C<Params::Check::check()>. The value must be an
integer, indicating the number of wrapper functions inserted between
the real function call and C<Params::Check::check()>.

Example wrapper function, using a custom stacktrace:

    sub check {
        my ($template, $args_in) = @_;

        local $Params::Check::WARNINGS_FATAL = 1;
        local $Params::Check::CALLER_DEPTH = $Params::Check::CALLER_DEPTH + 1;
        my $args_out = Params::Check::check($template, $args_in);

        my_stacktrace(Params::Check::last_error) unless $args_out;

        return $args_out;
    }

Default is 0;

=head1 Acknowledgements

Thanks to Richard Soderberg for his performance improvements.

=head1 BUG REPORTS

Please report bugs or other issues to E<lt>bug-params-check@rt.cpan.orgE<gt>.

=head1 AUTHOR

This module by Jos Boumans E<lt>kane@cpan.orgE<gt>.

=head1 COPYRIGHT

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


=cut

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