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.\" ========================================================================
.\"
.IX Title "Data::Util 3pm"
.TH Data::Util 3pm 2024-03-07 "perl v5.38.2" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH NAME
Data::Util \- A selection of utilities for data and data types
.SH VERSION
.IX Header "VERSION"
This document describes Data::Util version 0.67
.SH SYNOPSIS
.IX Header "SYNOPSIS"
.Vb 1
\&        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, \*(AqFoo\*(Aq);
\&                # ...
\&        }
\&
\&        use Data::Util qw(:check);
\&
\&        sub bar{
\&                my $x = shift;
\&                if(is_scalar_ref $x){
\&                        # $x is an array reference
\&                }
\&                # ...
\&                elsif(is_instance $x, \*(AqFoo\*(Aq){
\&                        # $x is an instance of Foo
\&                }
\&                # ...
\&        }
\&
\&        # miscelaneous
\&        use Data::Util qw(:all);
\&
\&        my $x = anon_scalar();
\&        $x = anon_scalar($x); # OK
\&
\&        my $stash = get_stash(\*(AqFoo\*(Aq);
\&
\&        install_subroutine(\*(AqFoo\*(Aq,
\&                hello  => sub{ "Hello!\en" },
\&                goodby => sub{ "Goodby!\en" },
\&        );
\&
\&        print Foo::hello(); # Hello!
\&
\&        my($pkg, $name) = get_code_info(\e&Foo::hello); # => (\*(AqFoo\*(Aq, \*(Aqhello\*(Aq)
\&        my $fqn         = get_code_info(\e&Foo::hello); # =>  \*(AqFoo::hello\*(Aq
\&        my $code        = get_code_ref(\*(AqFoo\*(Aq, \*(Aqhello\*(Aq);  # => \e&Foo::hello
\&
\&        uninstall_subroutine(\*(AqFoo\*(Aq, qw(hello goodby));
\&
\&    # simple format for errro messages (not the same as Data::Dumper)
\&        print neat("Hello!\en"); # => "Hello!\en"
\&        print neat(3.14);       # => 3.14
\&        print neat(undef);      # => undef
.Ve
.SH DESCRIPTION
.IX Header "DESCRIPTION"
This module provides utility functions for data and data types,
including functions for subroutines and symbol table hashes (stashes).
.PP
This module makes for a pure Perl and XS implementation.
.PP
However, if you want to use the full capacity of it, we recommend you to opt
for the XS backend.
.PP
There are many benchmarks in the \fIDIST\-DIR/benchmark/\fR directory.
.SH INTERFACE
.IX Header "INTERFACE"
.SS "Check functions"
.IX Subsection "Check functions"
Check functions are introduced by the \f(CW\*(C`:check\*(C'\fR import tag, which check
the argument type and return a bool.
.PP
These functions also check for overloading magic, e.g. \f(CW\*(C`${}\*(C'\fR corresponds to a SCALAR reference.
.IP is_scalar_ref(value) 4
.IX Item "is_scalar_ref(value)"
Checks for a SCALAR reference.
.IP is_array_ref(value) 4
.IX Item "is_array_ref(value)"
Checks for an ARRAY reference.
.IP is_hash_ref(value) 4
.IX Item "is_hash_ref(value)"
Checks for a HASH reference.
.IP is_code_ref(value) 4
.IX Item "is_code_ref(value)"
Checks for a CODE reference.
.IP is_glob_ref(value) 4
.IX Item "is_glob_ref(value)"
Checks for a GLOB reference.
.IP is_rx(value) 4
.IX Item "is_rx(value)"
Checks for a regular expression reference generated by the \f(CW\*(C`qr//\*(C'\fR operator.
.IP "is_instance(value, class)" 4
.IX Item "is_instance(value, class)"
Checks for an instance of \fIclass\fR.
.Sp
It is equivalent to the following statement:
\&\f(CW\*(C`Scalar::Util::blessed($value) && $value\->isa($class)\*(C'\fR.
.IP is_invocant(value) 4
.IX Item "is_invocant(value)"
Checks for an invocant, i.e. a blessed reference or existent package name.
.Sp
If \fIvalue\fR is a valid class name but does not exist, it will return false.
.IP is_value(value) 4
.IX Item "is_value(value)"
Checks whether \fIvalue\fR is a primitive value, i.e. a defined, non-ref, and
non-type-glob value.
.Sp
This function has no counterpart for validation.
.IP is_string(value) 4
.IX Item "is_string(value)"
Checks whether \fIvalue\fR is a string with non-zero-length contents,
equivalent to \f(CW\*(C`is_value($value) && length($value) > 0\*(C'\fR.
.Sp
This function has no counterpart for validation.
.IP is_number(value) 4
.IX Item "is_number(value)"
Checks whether \fIvalue\fR is a number.
Here, a \fBnumber\fR means that the perl parser can understand it and that
the perl numeric converter (e.g. invoked by \f(CW\*(C`sprintf \*(Aq%g\*(Aq, $value\*(C'\fR)
doesn't complain about it.
.Sp
It is similar to \f(CWScalar::Util::looks_like_number()\fR
but refuses \f(CW\*(C`infinity\*(C'\fR, \f(CW\*(C`not a number\*(C'\fR and \f(CW"0 but true"\fR.
Note that \f(CW\*(C`9**9**9\*(C'\fR makes \f(CW\*(C`infinity\*(C'\fR and \f(CW\*(C`9**9**9 \- 9**9**9\*(C'\fR makes
\&\f(CW\*(C`not a number\*(C'\fR.
.Sp
This function has no counterpart for validation.
.IP is_integer(value) 4
.IX Item "is_integer(value)"
Checks whether \fIvalue\fR is an integer.
An \fBinteger\fR is also a \fBnumber\fR, so this function
refuses \f(CW\*(C`infinity\*(C'\fR and \f(CW\*(C`not a number\*(C'\fR. See also \f(CWis_number()\fR.
.Sp
This function has no counterpart for validation.
.SS "Validating functions"
.IX Subsection "Validating functions"
Validating functions are introduced by the \f(CW\*(C`:validate\*(C'\fR tag which checks for
the argument and returns the first argument.
These are like the \f(CW\*(C`:check\*(C'\fR functions but dies if the argument type
is invalid.
.PP
These functions also checks overloading magic, e.g. \f(CW\*(C`${}\*(C'\fR for a SCALAR reference.
.IP scalar_ref(value) 4
.IX Item "scalar_ref(value)"
Validates a SCALAR reference.
.IP array_ref(value) 4
.IX Item "array_ref(value)"
Validates an ARRAY reference.
.IP hash_ref(value) 4
.IX Item "hash_ref(value)"
Validates a HASH reference.
.IP code_ref(value) 4
.IX Item "code_ref(value)"
Validates a CODE reference.
.IP glob_ref(value) 4
.IX Item "glob_ref(value)"
Validates a GLOB reference.
.IP rx(value) 4
.IX Item "rx(value)"
Validates a regular expression reference.
.IP "instance(value, class)" 4
.IX Item "instance(value, class)"
Validates an instance of \fIclass\fR.
.IP invocant(value) 4
.IX Item "invocant(value)"
Validates an invocant, i.e. a blessed reference or existent package name.
.Sp
If \fIvalue\fR is a valid class name and the class exists, then it returns
the canonical class name, which is logically cleaned up. That is, it runs
\&\f(CW\*(C`$value =~ s/^::(?:main::)*//;\*(C'\fR before returning it.
.Sp
NOTE:
Canonization is done so due to an inconsistency between Perl versions. 
For instance:
.Sp
.Vb 3
\&        package ::Foo; # OK
\&        my $x = bless {}, \*(Aq::Foo\*(Aq; # OK
\&        ref($x)\->isa(\*(AqFoo\*(Aq); # Fatal
.Ve
.Sp
The last code snippet causes a fatal error:
\&\f(CW\*(C`Can\*(Aqt call method "isa" without package or object reference\*(C'\fR.
However, \f(CW\*(C`invocant(ref $x)\->isa(\*(AqFoo\*(Aq)\*(C'\fR is always OK.
.SS "Miscellaneous utilities"
.IX Subsection "Miscellaneous utilities"
There are some other utility functions you can import from this module.
.IP \fBanon_scalar()\fR 4
.IX Item "anon_scalar()"
Generates an anonymous scalar reference to \f(CW\*(C`undef\*(C'\fR.
.IP anon_scalar(value) 4
.IX Item "anon_scalar(value)"
Generates an anonymous scalar reference to the copy of \fIvalue\fR.
.Sp
It is equivalent to \f(CW\*(C`do{ my $tmp = $value; \e$tmp; }\*(C'\fR.
.IP neat(value) 4
.IX Item "neat(value)"
Returns a neat string that is suitable to display.
.Sp
This is a smart version of \f(CW\*(C`<do{ defined($value) ? qq{"$value"} : \*(Aqundef\*(Aq }\*(C'\fR>.
.IP get_stash(invocant) 4
.IX Item "get_stash(invocant)"
Returns the symbol table hash (also known as \fBstash\fR) of \fIinvocant\fR
if the stash exists.
.IP "install_subroutine(package, name => subr [, ...])" 4
.IX Item "install_subroutine(package, name => subr [, ...])"
Installs \fIsubr\fR into \fIpackage\fR as \fIname\fR.
.Sp
It is similar to
\&\f(CW\*(C`do{ no strict \*(Aqrefs\*(Aq; *{$package.\*(Aq::\*(Aq.$name} = \e&subr; }\*(C'\fR.
In addition, if \fIsubr\fR is an anonymous subroutine, it is located into
\&\fIpackage\fR as a named subroutine \fI&package::name\fR.
.Sp
For example:
.Sp
.Vb 5
\&        install_subroutine($pkg,   say => sub{ print @_, "\en" });
\&        install_subroutine($pkg,
\&                one => \e&_one,
\&                two => \e&_two,
\&        );
\&
\&        # accepts a HASH reference
\&        install_subroutine($pkg, { say => sub{ print @_, "\en" }); #
.Ve
.Sp
To re-install \fIsubr\fR, use \f(CW\*(C`no warnings \*(Aqredefine\*(Aq\*(C'\fR directive:
.Sp
.Vb 2
\&        no warnings \*(Aqredefine\*(Aq;
\&        install_subroutine($package, $name => $subr);
.Ve
.IP "uninstall_subroutine(package, names...)" 4
.IX Item "uninstall_subroutine(package, names...)"
Uninstalls \fInames\fR from \fIpackage\fR.
.Sp
It is similar to \f(CWSub::Delete::delete_sub()\fR, but uninstall multiple
subroutines at a time.
.Sp
If you want to specify deleted subroutines, you can supply
\&\f(CW\*(C`name => \e&subr\*(C'\fR pairs.
.Sp
For example:
.Sp
.Vb 1
\&        uninstall_subroutine(\*(AqFoo\*(Aq, \*(Aqhello\*(Aq);
\&
\&        uninstall_subroutine(\*(AqFoo\*(Aq, hello => \e&Bar::hello);
\&
\&        uninstall_subroutine($pkg,
\&                one => \e&_one,
\&                two => \e&_two,
\&        );
\&
\&        # accepts a HASH reference
\&        uninstall_subroutine(\e$pkg, { hello => \e&Bar::hello });
.Ve
.IP get_code_info(subr) 4
.IX Item "get_code_info(subr)"
Returns a pair of elements, the package name and the subroutine name of \fIsubr\fR.
.Sp
It is similar to \f(CWSub::Identify::get_code_info()\fR, but it returns the fully
qualified name in scalar context.
.IP "get_code_ref(package, name, flag?)" 4
.IX Item "get_code_ref(package, name, flag?)"
Returns \fI&package::name\fR if it exists, not touching the symbol in the stash.
.Sp
if \fIflag\fR is a string \f(CW\*(C`\-create\*(C'\fR, it returns \fI&package::name\fR regardless of
its existence. That is, it is equivalent to
\&\f(CW\*(C`do{ no strict \*(Aqrefs\*(Aq; \e&{package . \*(Aq::\*(Aq . $name} }\*(C'\fR.
.Sp
For example:
.Sp
.Vb 2
\&        $code = get_code_ref($pkg, $name);          # like  *{$pkg.\*(Aq::\*(Aq.$name}{CODE}
\&        $code = get_code_ref($pkg, $name, \-create); # like \e&{$pkg.\*(Aq::\*(Aq.$name}
.Ve
.IP "curry(subr, args and/or placeholders)" 4
.IX Item "curry(subr, args and/or placeholders)"
Makes \fIsubr\fR curried and returns the curried subroutine.
.Sp
This is also considered as lightweight closures.
.Sp
See also Data::Util::Curry.
.IP "modify_subroutine(subr, ...)" 4
.IX Item "modify_subroutine(subr, ...)"
Modifies \fIsubr\fR with subroutine modifiers and returns the modified subroutine.
This is also considered as lightweight closures.
.Sp
\&\fIsubr\fR must be a code reference or callable object.
.Sp
Optional arguments:
\&\f(CW\*(C`before => [subroutine(s)]\*(C'\fR called before \fIsubr\fR.
\&\f(CW\*(C`around => [subroutine(s)]\*(C'\fR called around \fIsubr\fR.
\&\f(CW\*(C`after  => [subroutine(s)]\*(C'\fR called after  \fIsubr\fR.
.Sp
This seems a constructor of modified subroutines and
\&\f(CWsubroutine_modifier()\fR is property accessors, but it does not bless the
modified subroutines.
.IP subroutine_modifier(subr) 4
.IX Item "subroutine_modifier(subr)"
Returns whether \fIsubr\fR is a modified subroutine.
.IP "subroutine_modifier(modified_subr, property)" 4
.IX Item "subroutine_modifier(modified_subr, property)"
Gets \fIproperty\fR from \fImodified\fR.
.Sp
Valid properties are: \f(CW\*(C`before\*(C'\fR, \f(CW\*(C`around\*(C'\fR, \f(CW\*(C`after\*(C'\fR.
.IP "subroutine_modifier(modified_subr, modifier => [subroutine(s)])" 4
.IX Item "subroutine_modifier(modified_subr, modifier => [subroutine(s)])"
Adds subroutine \fImodifier\fR to \fImodified_subr\fR.
.Sp
Valid modifiers are: \f(CW\*(C`before\*(C'\fR, \f(CW\*(C`around\*(C'\fR, \f(CW\*(C`after\*(C'\fR.
.IP "mkopt(input, moniker, require_unique, must_be)" 4
.IX Item "mkopt(input, moniker, require_unique, must_be)"
Produces an array of an array reference from \fIinput\fR.
.Sp
It is compatible with \f(CWData::OptList::mkopt()\fR. In addition to it,
\&\fImust_be\fR can be a HASH reference with \f(CW\*(C`name => type\*(C'\fR pairs.
.Sp
For example:
.Sp
.Vb 2
\&        my $optlist = mkopt([\*(Aqfoo\*(Aq, bar => [42]], $moniker, $uniq, { bar => \*(AqARRAY\*(Aq });
\&        # $optlist == [[foo => undef], [bar => [42]]
.Ve
.IP "mkopt_hash(input, moniker, must_be)" 4
.IX Item "mkopt_hash(input, moniker, must_be)"
Produces a hash reference from \fIinput\fR.
.Sp
It is compatible with \f(CWData::OptList::mkopt_hash()\fR. In addition to it,
\&\fImust_be\fR can be a HASH reference with \f(CW\*(C`name => type\*(C'\fR pairs.
.Sp
For example:
.Sp
.Vb 2
\&        my $optlist = mkopt([\*(Aqfoo\*(Aq, bar => [42]], $moniker, { bar => \*(AqARRAY\*(Aq });
\&        # $optlist == {foo => undef, bar => [42]}
.Ve
.SH "ENVIRONMENT VARIABLES"
.IX Header "ENVIRONMENT VARIABLES"
.SS DATA_UTIL_PUREPERL
.IX Subsection "DATA_UTIL_PUREPERL"
If true, \f(CW\*(C`Data::Util\*(C'\fR uses the pure Perl implementation.
.SH DEPENDENCIES
.IX Header "DEPENDENCIES"
Perl 5.10 or later.
.PP
If you have a C compiler, you can use the XS backend.
.PP
A pure Perl backend/implementation is also made available in case you have no C
compiler handy (unlikely!).
.SH "BUGS AND LIMITATIONS"
.IX Header "BUGS AND LIMITATIONS"
No bugs have been reported.
.PP
Please report any bugs or feature requests to the author.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
Scalar::Util.
.PP
overload.
.PP
Params::Util.
.PP
Sub::Install.
.PP
Sub::Identify.
.PP
Sub::Delete.
.PP
Sub::Curry.
.PP
Class::MOP.
.PP
Class::Method::Modifiers.
.PP
Data::OptList.
.PP
Mouse
.SH AUTHOR
.IX Header "AUTHOR"
Goro Fuji(gfx) <gfuji(at)cpan.org>.
.SH "LICENSE AND COPYRIGHT"
.IX Header "LICENSE AND COPYRIGHT"
Copyright (c) 2008\-2010, Goro Fuji <gfuji(at)cpan.org>. All rights reserved.
.PP
This module is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.