# NAME Data::Util - A selection of utilities for data and data types # VERSION This document describes Data::Util version 0.64 # SYNOPSIS use Data::Util qw(:validate); sub foo{ # they will die if invalid values are supplied my $sref = scalar_ref(shift); my $aref = array_ref(shift); my $href = hash_ref(shift); my $cref = code_ref(shift); my $gref = glob_ref(shift); my $rx = rx(shift); # regular expression my $obj = instance(shift, 'Foo'); # ... } use Data::Util qw(:check); sub bar{ my $x = shift; if(is_scalar_ref $x){ # $x is an array reference } # ... elsif(is_instance $x, 'Foo'){ # $x is an instance of Foo } # ... } # miscelaneous use Data::Util qw(:all); my $x = anon_scalar(); $x = anon_scalar($x); # OK my $stash = get_stash('Foo'); install_subroutine('Foo', hello => sub{ "Hello!\n" }, goodby => sub{ "Goodby!\n" }, ); print Foo::hello(); # Hello! my($pkg, $name) = get_code_info(\&Foo::hello); # => ('Foo', 'hello') my $fqn = get_code_info(\&Foo::hello); # => 'Foo::hello' my $code = get_code_ref('Foo', 'hello'); # => \&Foo::hello uninstall_subroutine('Foo', qw(hello goodby)); # simple format for errro messages (not the same as Data::Dumper) print neat("Hello!\n"); # => "Hello!\n" print neat(3.14); # => 3.14 print neat(undef); # => undef # DESCRIPTION This module provides utility functions for data and data types, including functions for subroutines and symbol table hashes (stashes). The implementation of this module is both Pure Perl and XS, so if you have a C compiler, all the functions this module provides are really faster. There are many benchmarks in the `DIST-DIR/benchmark/` directory. # INTERFACE ## Check functions Check functions are introduced by the `:check` import tag, which check the argument type and return a bool. These functions also checks overloading magic, e.g. `${}` for a SCALAR reference. - is\_scalar\_ref(value) For a SCALAR reference. - is\_array\_ref(value) For an ARRAY reference. - is\_hash\_ref(value) For a HASH reference. - is\_code\_ref(value) For a CODE reference. - is\_glob\_ref(value) For a GLOB reference. - is\_rx(value) For a regular expression reference generated by the `qr//` operator. - is\_instance(value, class) For an instance of _class_. It is equivalent to something like `Scalar::Util::blessed($value) && $value->isa($class)`. - is\_invocant(value) For an invocant, i.e. a blessed reference or existent package name. If _value_ is a valid class name but does not exist, it will return false. - is\_value(value) Checks whether _value_ is a primitive value, i.e. a defined, non-ref, and non-type-glob value. This function has no counterpart for validation. - is\_string(value) Checks whether _value_ is a string with non-zero-length contents, equivalent to `is_value($value) && length($value) > 0`. This function has no counterpart for validation. - is\_number(value) Checks whether _value_ is a number. Here, a **number** means that the perl parser can understand it and that the perl numeric converter (e.g. invoked by `sprintf '%g', $value`) doesn't complain about it. It is similar to `Scalar::Util::looks_like_number()` but refuses `infinity`, `not a number` and `"0 but true"`. Note that `9**9**9` makes `infinity` and `9**9**9 - 9**9**9` makes `not a number`. This function has no counterpart for validation. - is\_integer(value) Checks whether _value_ is an integer. An **integer** is also a **number**, so this function refuses `infinity` and `not a number`. See also `is_number()`. This function has no counterpart for validation. ## Validating functions Validating functions are introduced by the `:validate` tag which check the argument and returns the first argument. These are like the `:check` functions but dies if the argument type is invalid. These functions also checks overloading magic, e.g. `${}` for a SCALAR reference. - scalar\_ref(value) For a SCALAR reference. - array\_ref(value) For an ARRAY reference. - hash\_ref(value) For a HASH reference. - code\_ref(value) For a CODE reference. - glob\_ref(value) For a GLOB reference. - rx(value) For a regular expression reference. - instance(value, class) For an instance of _class_. - invocant(value) For an invocant, i.e. a blessed reference or existent package name. If _value_ is a valid class name and the class exists, then it returns the canonical class name, which is logically cleaned up. That is, it does `$value =~ s/^::(?:main::)*//;` before returns it. NOTE: The canonization is because some versions of perl has an inconsistency on package names: package ::Foo; # OK my $x = bless {}, '::Foo'; # OK ref($x)->isa('Foo'); # Fatal The last sentence causes a fatal error: `Can't call method "isa" without package or object reference`. However, `invocant(ref $x)->isa('Foo')` is always OK. ## Miscellaneous utilities There are some other utility functions you can import from this module. - anon\_scalar() Generates an anonymous scalar reference to `undef`. - anon\_scalar(value) Generates an anonymous scalar reference to the copy of _value_. It is equivalent to `do{ my $tmp = $value; \$tmp; }`. - neat(value) Returns a neat string that is suitable to display. This is a smart version of `. - get\_stash(invocant) Returns the symbol table hash (also known as **stash**) of _invocant_ if the stash exists. - install\_subroutine(package, name => subr \[, ...\]) Installs _subr_ into _package_ as _name_. It is similar to `do{ no strict 'refs'; *{$package.'::'.$name} = \&subr; }`. In addition, if _subr_ is an anonymous subroutine, it is located into _package_ as a named subroutine _&package::name_. For example: install_subroutine($pkg, say => sub{ print @_, "\n" }); install_subroutine($pkg, one => \&_one, two => \&_two, ); # accepts a HASH reference install_subroutine($pkg, { say => sub{ print @_, "\n" }); # To re-install _subr_, use `no warnings 'redefine'` directive: no warnings 'redefine'; install_subroutine($package, $name => $subr); - uninstall\_subroutine(package, names...) Uninstalls _names_ from _package_. It is similar to `Sub::Delete::delete_sub()`, but uninstall multiple subroutines at a time. If you want to specify deleted subroutines, you can supply `name => \&subr` pairs. For example: uninstall_subroutine('Foo', 'hello'); uninstall_subroutine('Foo', hello => \&Bar::hello); uninstall_subroutine($pkg, one => \&_one, two => \&_two, ); # accepts a HASH reference uninstall_subroutine(\$pkg, { hello => \&Bar::hello }); - get\_code\_info(subr) Returns a pair of elements, the package name and the subroutine name of _subr_. It is similar to `Sub::Identify::get_code_info()`, but it returns the fully qualified name in scalar context. - get\_code\_ref(package, name, flag?) Returns _&package::name_ if it exists, not touching the symbol in the stash. if _flag_ is a string `-create`, it returns _&package::name_ regardless of its existence. That is, it is equivalent to `do{ no strict 'refs'; \&{package . '::' . $name} }`. For example: $code = get_code_ref($pkg, $name); # like *{$pkg.'::'.$name}{CODE} $code = get_code_ref($pkg, $name, -create); # like \&{$pkg.'::'.$name} - curry(subr, args and/or placeholders) Makes _subr_ curried and returns the curried subroutine. This is also considered as lightweight closures. See also [Data::Util::Curry](https://metacpan.org/pod/Data::Util::Curry). - modify\_subroutine(subr, ...) Modifies _subr_ with subroutine modifiers and returns the modified subroutine. This is also considered as lightweight closures. _subr_ must be a code reference or callable object. Optional arguments: `before => [subroutine(s)]` called before _subr_. `around => [subroutine(s)]` called around _subr_. `after => [subroutine(s)]` called after _subr_. This seems a constructor of modified subroutines and `subroutine_modifier()` is property accessors, but it does not bless the modified subroutines. - subroutine\_modifier(subr) Returns whether _subr_ is a modified subroutine. - subroutine\_modifier(modified\_subr, property) Gets _property_ from _modified_. Valid properties are: `before`, `around`, `after`. - subroutine\_modifier(modified\_subr, modifier => \[subroutine(s)\]) Adds subroutine _modifier_ to _modified\_subr_. Valid modifiers are: `before`, `around`, `after`. - mkopt(input, moniker, require\_unique, must\_be) Produces an array of an array reference from _input_. It is compatible with `Data::OptList::mkopt()`. In addition to it, _must\_be_ can be a HASH reference with `name => type` pairs. For example: my $optlist = mkopt(['foo', bar => [42]], $moniker, $uniq, { bar => 'ARRAY' }); # $optlist == [[foo => undef], [bar => [42]] - mkopt\_hash(input, moniker, must\_be) Produces a hash reference from _input_. It is compatible with `Data::OptList::mkopt_hash()`. In addition to it, _must\_be_ can be a HASH reference with `name => type` pairs. For example: my $optlist = mkopt(['foo', bar => [42]], $moniker, { bar => 'ARRAY' }); # $optlist == {foo => undef, bar => [42]} # ENVIRONMENT VARIABLES ## DATA\_UTIL\_PUREPERL If true, `Data::Util` uses the Pure Perl implementation. # DEPENDENCIES Perl 5.8.1 or later. If you have a C compiler, you can use the XS backend, but the Pure Perl backend is also available if you have no C compilers. # BUGS AND LIMITATIONS No bugs have been reported. Please report any bugs or feature requests to the author. # SEE ALSO [Scalar::Util](https://metacpan.org/pod/Scalar::Util). [overload](https://metacpan.org/pod/overload). [Params::Util](https://metacpan.org/pod/Params::Util). [Sub::Install](https://metacpan.org/pod/Sub::Install). [Sub::Identify](https://metacpan.org/pod/Sub::Identify). [Sub::Delete](https://metacpan.org/pod/Sub::Delete). [Sub::Curry](https://metacpan.org/pod/Sub::Curry). [Class::MOP](https://metacpan.org/pod/Class::MOP). [Class::Method::Modifiers](https://metacpan.org/pod/Class::Method::Modifiers). [Data::OptList](https://metacpan.org/pod/Data::OptList). [Mouse](https://metacpan.org/pod/Mouse) # AUTHOR Goro Fuji(gfx) <gfuji(at)cpan.org>. # LICENSE AND COPYRIGHT Copyright (c) 2008-2010, Goro Fuji <gfuji(at)cpan.org>. All rights reserved. This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.