VERSION

version 1.100850

SYNOPSIS

use Data::Miscellany qw/set_push flex_grep/;
my @foo = (1, 2, 3, 4);
set_push @foo, 3, 1, 5, 1, 6;
# @foo is now (1, 2, 3, 4, 5, 6);
flex_grep('foo', [ qw/foo bar baz/ ]); # true
flex_grep('foo', [ qw/bar baz flurble/ ]); # false
flex_grep('foo', 1..4, 'flurble', [ qw/foo bar baz/ ]); # true
flex_grep('foo', 1..4, [ [ 'foo' ] ], [ qw/bar baz/ ]); # false

DESCRIPTION

This is a collection of miscellaneous subroutines useful in wide but varying scenarios; a catch-all module for things that don't obviously belong anywhere else. Obviously what's useful differs from person to person, but this particular collection should be useful in object-oriented frameworks, such as Class::Scaffold and Data::Conveyor.

FUNCTIONS

set_push(ARRAY, LIST)

Like "push()", but only pushes the item(s) onto the list indicated by the list or list ref (the first argument) if the list doesn't already contain it.

Example:

    @foo = (1, 2, 3, 4);
    set_push @foo, 3, 1, 5, 1, 6;
    # @foo is now (1, 2, 3, 4, 5, 6)

flatten()

If the first argument is an array reference, it returns the dereferenced array. If the first argument is undefined (or there are no arguments), it returns the empty list. Otherwise the argument list is returned as is.

flex_grep(SCALAR, LIST)

Like "grep()", but compares the first argument to each flattened (see "flatten()") version of each element of the list.

Examples:

    flex_grep('foo', [ qw/foo bar baz/ ])                     # true
    flex_grep('foo', [ qw/bar baz flurble/ ])                 # false
    flex_grep('foo', 1..4, 'flurble', [ qw/foo bar baz/ ])    # true
    flex_grep('foo', 1..4, [ [ 'foo' ] ], [ qw/bar baz/ ])    # false

is_deeply()

Like Test::More's "is_deeply()" except that this version respects stringification overloads. If a package overloads stringification, it means that it specifies how it wants to be compared. Recent versions of Test::More break this behaviour, so here is a working version of "is_deeply()". This subroutine only does the comparison; there are no test diagnostics or results recorded or printed anywhere.

eq_array()

Like Test::More's "eq_array()" except that this version respects stringification overloads. If a package overloads stringification, it means that it specifies how it wants to be compared. Recent versions of Test::More break this behaviour, so here is a working version of "eq_array()". This subroutine only does the comparison; there are no test diagnostics or results recorded or printed anywhere.

eq_hash()

Like Test::More's "eq_hash()" except that this version respects stringification overloads. If a package overloads stringification, it means that it specifies how it wants to be compared. Recent versions of Test::More break this behaviour, so here is a working version of "eq_hash()". This subroutine only does the comparison; there are no test diagnostics or results recorded or printed anywhere.

is_defined(SCALAR)

A kind of "defined()" that is aware of Class::Value, which has its own views of what is a defined value and what isn't. The issue arose since Class::Value objects are supposed to be used transparently, mixed with normal scalar values. However, it is not possible to overload ``definedness'', and "defined()" used on a value object always returns true since the object reference certainly exists. However, what we want to know is whether the value encapsulated by the value object is defined. Additionally, each value class can have its own ideas of when its encapsulated value is defined. Therefore, Class::Value has an "is_defined()" method.

This subroutine checks whether its argument is a value object and if so, calls the value object's "is_defined()" method. Otherwise, the normal "defined()" is used.

value_of(SCALAR)

Stringifies its argument, but returns undefined values (per "is_defined()") as "undef".

str_value_of(SCALAR)

Stringifies its argument, but returns undefined values (per "is_defined()") as the empty string.

class_map(SCALAR, HASH)

Takes an object or class name as the first argument (if it's an object, the class name used will be the package name the object is blessed into). Takes a hash whose keys are class names as the second argument. The hash values are completely arbitrary.

Looks up the given class name in the hash and returns the corresponding value. If no such hash key is found, the class hierarchy for the given class name is traversed depth-first and checked against the hash keys in turn. The first value found is returned.

If no key is found, a special key, "UNIVERSAL" is used.

As an example of how this might be used, consider a hierarchy of exception classes. When evaluating each exception, we want to know how severe this exception is, so we define constants for "RC_OK" (meaning it's informational only), "RC_ERROR" (meaning some sort of action should be taken) and "RC_INTERNAL_ERROR" (meaning something has gone badly wrong and we might halt processing). In the following table assume that if you have names like "Foo::Bar" and "Foo::Bar::Baz", then the latter subclasses the former.

    %map = (
        'UNIVERSAL'                                => RC_INTERNAL_ERROR,
        'My::Exception::Business'                  => RC_ERROR,
        'My::Exception::Internal'                  => RC_INTERNAL_ERROR,
        'My::Exception::Business::ValueNormalized' => RC_OK,
    );

Assuming that "My::Exception::Business::IllegalValue" exists and that it subclasses "My::Exception::Business", here are some outcomes:

    class_map('My::Exception::Business::IllegalValue', \%map)     # RC_ERROR
    class_map('My::Exception::Business::ValueNormalzed', \%map)   # RC_OK

trim(STRING)

Trims off whitespace at the beginning and end of the string and returns the trimmed string.

INSTALLATION

See perlmodinstall for information and options on installing Perl modules.

AVAILABILITY

The latest version of this module is available from the Comprehensive Perl Archive Network (CPAN). Visit <http://www.perl.com/CPAN/> to find a CPAN site near you, or see <http://search.cpan.org/dist/Data-Miscellany/>.

The development version lives at <http://github.com/hanekomu/Data-Miscellany/>. Instead of sending patches, please fork this project using the standard git and github infrastructure.

AUTHOR

  Marcel Gruenauer <[email protected]>

COPYRIGHT AND LICENSE

This software is copyright (c) 2004 by Marcel Gruenauer.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.