======================================================================== * README.md ======================================================================== # NAME Params::Util - Simple, compact and correct param-checking functions # SYNOPSIS # Import some functions use Params::Util qw{_SCALAR _HASH _INSTANCE}; # If you are lazy, or need a lot of them... use Params::Util ':ALL'; sub foo { my $object = _INSTANCE(shift, 'Foo') or return undef; my $image = _SCALAR(shift) or return undef; my $options = _HASH(shift) or return undef; # etc... } # DESCRIPTION `Params::Util` provides a basic set of importable functions that makes checking parameters a hell of a lot easier While they can be (and are) used in other contexts, the main point behind this module is that the functions **both** Do What You Mean, and Do The Right Thing, so they are most useful when you are getting params passed into your code from someone and/or somewhere else and you can't really trust the quality. Thus, `Params::Util` is of most use at the edges of your API, where params and data are coming in from outside your code. The functions provided by `Params::Util` check in the most strictly correct manner known, are documented as thoroughly as possible so their exact behaviour is clear, and heavily tested so make sure they are not fooled by weird data and Really Bad Things. To use, simply load the module providing the functions you want to use as arguments (as shown in the SYNOPSIS). To aid in maintainability, `Params::Util` will **never** export by default. You must explicitly name the functions you want to export, or use the `:ALL` param to just have it export everything (although this is not recommended if you have any \_FOO functions yourself with which future additions to `Params::Util` may clash) # FUNCTIONS ## \_STRING $string The `_STRING` function is intended to be imported into your package, and provides a convenient way to test to see if a value is a normal non-false string of non-zero length. Note that this will NOT do anything magic to deal with the special `'0'` false negative case, but will return it. # '0' not considered valid data my $name = _STRING(shift) or die "Bad name"; # '0' is considered valid data my $string = _STRING($_[0]) ? shift : die "Bad string"; Please also note that this function expects a normal string. It does not support overloading or other magic techniques to get a string. Returns the string as a conveince if it is a valid string, or `undef` if not. ## \_IDENTIFIER $string The `_IDENTIFIER` function is intended to be imported into your package, and provides a convenient way to test to see if a value is a string that is a valid Perl identifier. Returns the string as a convenience if it is a valid identifier, or `undef` if not. ## \_CLASS $string The `_CLASS` function is intended to be imported into your package, and provides a convenient way to test to see if a value is a string that is a valid Perl class. This function only checks that the format is valid, not that the class is actually loaded. It also assumes "normalised" form, and does not accept class names such as `::Foo` or `D'Oh`. Returns the string as a convenience if it is a valid class name, or `undef` if not. ## \_CLASSISA $string, $class The `_CLASSISA` function is intended to be imported into your package, and provides a convenient way to test to see if a value is a string that is a particularly class, or a subclass of it. This function checks that the format is valid and calls the ->isa method on the class name. It does not check that the class is actually loaded. It also assumes "normalised" form, and does not accept class names such as `::Foo` or `D'Oh`. Returns the string as a convenience if it is a valid class name, or `undef` if not. ## \_CLASSDOES $string, $role This routine behaves exactly like `["_CLASSISA"](#_classisa)`, but checks with `->DOES` rather than `->isa`. This is probably only a good idea to use on Perl 5.10 or later, when [UNIVERSAL::DOES](https://metacpan.org/pod/UNIVERSAL::DOES#DOES) has been implemented. ## \_SUBCLASS $string, $class The `_SUBCLASS` function is intended to be imported into your package, and provides a convenient way to test to see if a value is a string that is a subclass of a specified class. This function checks that the format is valid and calls the ->isa method on the class name. It does not check that the class is actually loaded. It also assumes "normalised" form, and does not accept class names such as `::Foo` or `D'Oh`. Returns the string as a convenience if it is a valid class name, or `undef` if not. ## \_NUMBER $scalar The `_NUMBER` function is intended to be imported into your package, and provides a convenient way to test to see if a value is a number. That is, it is defined and perl thinks it's a number. This function is basically a Params::Util-style wrapper around the [Scalar::Util](https://metacpan.org/pod/Scalar::Util) `looks_like_number` function. Returns the value as a convience, or `undef` if the value is not a number. ## \_POSINT $integer The `_POSINT` function is intended to be imported into your package, and provides a convenient way to test to see if a value is a positive integer (of any length). Returns the value as a convience, or `undef` if the value is not a positive integer. The name itself is derived from the XML schema constraint of the same name. ## \_NONNEGINT $integer The `_NONNEGINT` function is intended to be imported into your package, and provides a convenient way to test to see if a value is a non-negative integer (of any length). That is, a positive integer, or zero. Returns the value as a convience, or `undef` if the value is not a non-negative integer. As with other tests that may return false values, care should be taken to test via "defined" in boolean validy contexts. unless ( defined _NONNEGINT($value) ) { die "Invalid value"; } The name itself is derived from the XML schema constraint of the same name. ## \_SCALAR \\$scalar The `_SCALAR` function is intended to be imported into your package, and provides a convenient way to test for a raw and unblessed `SCALAR` reference, with content of non-zero length. For a version that allows zero length `SCALAR` references, see the `_SCALAR0` function. Returns the `SCALAR` reference itself as a convenience, or `undef` if the value provided is not a `SCALAR` reference. ## \_SCALAR0 \\$scalar The `_SCALAR0` function is intended to be imported into your package, and provides a convenient way to test for a raw and unblessed `SCALAR0` reference, allowing content of zero-length. For a simpler "give me some content" version that requires non-zero length, `_SCALAR` function. Returns the `SCALAR` reference itself as a convenience, or `undef` if the value provided is not a `SCALAR` reference. ## \_ARRAY $value The `_ARRAY` function is intended to be imported into your package, and provides a convenient way to test for a raw and unblessed `ARRAY` reference containing **at least** one element of any kind. For a more basic form that allows zero length ARRAY references, see the `_ARRAY0` function. Returns the `ARRAY` reference itself as a convenience, or `undef` if the value provided is not an `ARRAY` reference. ## \_ARRAY0 $value The `_ARRAY0` function is intended to be imported into your package, and provides a convenient way to test for a raw and unblessed `ARRAY` reference, allowing `ARRAY` references that contain no elements. For a more basic "An array of something" form that also requires at least one element, see the `_ARRAY` function. Returns the `ARRAY` reference itself as a convenience, or `undef` if the value provided is not an `ARRAY` reference. ## \_ARRAYLIKE $value The `_ARRAYLIKE` function tests whether a given scalar value can respond to array dereferencing. If it can, the value is returned. If it cannot, `_ARRAYLIKE` returns `undef`. ## \_HASH $value The `_HASH` function is intended to be imported into your package, and provides a convenient way to test for a raw and unblessed `HASH` reference with at least one entry. For a version of this function that allows the `HASH` to be empty, see the `_HASH0` function. Returns the `HASH` reference itself as a convenience, or `undef` if the value provided is not an `HASH` reference. ## \_HASH0 $value The `_HASH0` function is intended to be imported into your package, and provides a convenient way to test for a raw and unblessed `HASH` reference, regardless of the `HASH` content. For a simpler "A hash of something" version that requires at least one element, see the `_HASH` function. Returns the `HASH` reference itself as a convenience, or `undef` if the value provided is not an `HASH` reference. ## \_HASHLIKE $value The `_HASHLIKE` function tests whether a given scalar value can respond to hash dereferencing. If it can, the value is returned. If it cannot, `_HASHLIKE` returns `undef`. ## \_CODE $value The `_CODE` function is intended to be imported into your package, and provides a convenient way to test for a raw and unblessed `CODE` reference. Returns the `CODE` reference itself as a convenience, or `undef` if the value provided is not an `CODE` reference. ## \_CODELIKE $value The `_CODELIKE` is the more generic version of `_CODE`. Unlike `_CODE`, which checks for an explicit `CODE` reference, the `_CODELIKE` function also includes things that act like them, such as blessed objects that overload `'&{}'`. Please note that in the case of objects overloaded with '&{}', you will almost always end up also testing it in 'bool' context at some stage. For example: sub foo { my $code1 = _CODELIKE(shift) or die "No code param provided"; my $code2 = _CODELIKE(shift); if ( $code2 ) { print "Got optional second code param"; } } As such, you will most likely always want to make sure your class has at least the following to allow it to evaluate to true in boolean context. # Always evaluate to true in boolean context use overload 'bool' => sub () { 1 }; Returns the callable value as a convenience, or `undef` if the value provided is not callable. Note - This function was formerly known as \_CALLABLE but has been renamed for greater symmetry with the other \_XXXXLIKE functions. The use of \_CALLABLE has been deprecated. It will continue to work, but with a warning, until end-2006, then will be removed. I apologise for any inconvenience caused. ## \_INVOCANT $value This routine tests whether the given value is a valid method invocant. This can be either an instance of an object, or a class name. If so, the value itself is returned. Otherwise, `_INVOCANT` returns `undef`. ## \_INSTANCE $object, $class The `_INSTANCE` function is intended to be imported into your package, and provides a convenient way to test for an object of a particular class in a strictly correct manner. Returns the object itself as a convenience, or `undef` if the value provided is not an object of that type. ## \_INSTANCEDOES $object, $role This routine behaves exactly like `["_INSTANCE"](#_instance)`, but checks with `->DOES` rather than `->isa`. This is probably only a good idea to use on Perl 5.10 or later, when [UNIVERSAL::DOES](https://metacpan.org/pod/UNIVERSAL::DOES#DOES) has been implemented. ## \_REGEX $value The `_REGEX` function is intended to be imported into your package, and provides a convenient way to test for a regular expression. Returns the value itself as a convenience, or `undef` if the value provided is not a regular expression. ## \_SET \\@array, $class The `_SET` function is intended to be imported into your package, and provides a convenient way to test for set of at least one object of a particular class in a strictly correct manner. The set is provided as a reference to an `ARRAY` of objects of the class provided. For an alternative function that allows zero-length sets, see the `_SET0` function. Returns the `ARRAY` reference itself as a convenience, or `undef` if the value provided is not a set of that class. ## \_SET0 \\@array, $class The `_SET0` function is intended to be imported into your package, and provides a convenient way to test for a set of objects of a particular class in a strictly correct manner, allowing for zero objects. The set is provided as a reference to an `ARRAY` of objects of the class provided. For an alternative function that requires at least one object, see the `_SET` function. Returns the `ARRAY` reference itself as a convenience, or `undef` if the value provided is not a set of that class. ## \_HANDLE The `_HANDLE` function is intended to be imported into your package, and provides a convenient way to test whether or not a single scalar value is a file handle. Unfortunately, in Perl the definition of a file handle can be a little bit fuzzy, so this function is likely to be somewhat imperfect (at first anyway). That said, it is implement as well or better than the other file handle detectors in existance (and we stole from the best of them). ## \_DRIVER $string sub foo { my $class = _DRIVER(shift, 'My::Driver::Base') or die "Bad driver"; ... } The `_DRIVER` function is intended to be imported into your package, and provides a convenient way to load and validate a driver class. The most common pattern when taking a driver class as a parameter is to check that the name is a class (i.e. check against \_CLASS) and then to load the class (if it exists) and then ensure that the class returns true for the isa method on some base driver name. Return the value as a convenience, or `undef` if the value is not a class name, the module does not exist, the module does not load, or the class fails the isa test. # TO DO \- Add \_CAN to help resolve the UNIVERSAL::can debacle \- Would be even nicer if someone would demonstrate how the hell to build a Module::Install dist of the ::Util dual Perl/XS type. :/ \- Implement an assertion-like version of this module, that dies on error. \- Implement a Test:: version of this module, for use in testing # SUPPORT Bugs should be reported via the CPAN bug tracker at [http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Params-Util](http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Params-Util) For other issues, contact the author. # AUTHOR Adam Kennedy # SEE ALSO [Params::Validate](https://metacpan.org/pod/Params::Validate) # COPYRIGHT Copyright 2005 - 2012 Adam Kennedy. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. The full text of the license can be found in the LICENSE file included with this module. ======================================================================== * GPL-1 ======================================================================== GNU GENERAL PUBLIC LICENSE Version 1, February 1989 Copyright (C) 1989 Free Software Foundation, Inc. 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. Preamble The license agreements of most software companies try to keep users at the mercy of those companies. By contrast, our General Public License is intended to guarantee your freedom to share and change free software--to make sure the software is free for all its users. The General Public License applies to the Free Software Foundation's software and to any other program whose authors commit to using it. You can use it for your programs, too. 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We protect your rights with two steps: (1) copyright the software, and (2) offer you this license which gives you legal permission to copy, distribute and/or modify the software. Also, for each author's protection and ours, we want to make certain that everyone understands that there is no warranty for this free software. If the software is modified by someone else and passed on, we want its recipients to know that what they have is not the original, so that any problems introduced by others will not reflect on the original authors' reputations. The precise terms and conditions for copying, distribution and modification follow. GNU GENERAL PUBLIC LICENSE TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION 0. This License Agreement applies to any program or other work which contains a notice placed by the copyright holder saying it may be distributed under the terms of this General Public License. The "Program", below, refers to any such program or work, and a "work based on the Program" means either the Program or any work containing the Program or a portion of it, either verbatim or with modifications. Each licensee is addressed as "you". 1. You may copy and distribute verbatim copies of the Program's source code as you receive it, in any medium, provided that you conspicuously and appropriately publish on each copy an appropriate copyright notice and disclaimer of warranty; keep intact all the notices that refer to this General Public License and to the absence of any warranty; and give any other recipients of the Program a copy of this General Public License along with the Program. You may charge a fee for the physical act of transferring a copy. 2. You may modify your copy or copies of the Program or any portion of it, and copy and distribute such modifications under the terms of Paragraph 1 above, provided that you also do the following: a) cause the modified files to carry prominent notices stating that you changed the files and the date of any change; and b) cause the whole of any work that you distribute or publish, that in whole or in part contains the Program or any part thereof, either with or without modifications, to be licensed at no charge to all third parties under the terms of this General Public License (except that you may choose to grant warranty protection to some or all third parties, at your option). c) If the modified program normally reads commands interactively when run, you must cause it, when started running for such interactive use in the simplest and most usual way, to print or display an announcement including an appropriate copyright notice and a notice that there is no warranty (or else, saying that you provide a warranty) and that users may redistribute the program under these conditions, and telling the user how to view a copy of this General Public License. d) You may charge a fee for the physical act of transferring a copy, and you may at your option offer warranty protection in exchange for a fee. 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Each version is given a distinguishing version number. If the Program specifies a version number of the license which applies to it and "any later version", you have the option of following the terms and conditions either of that version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of the license, you may choose any version ever published by the Free Software Foundation. 8. If you wish to incorporate parts of the Program into other free programs whose distribution conditions are different, write to the author to ask for permission. For software which is copyrighted by the Free Software Foundation, write to the Free Software Foundation; we sometimes make exceptions for this. Our decision will be guided by the two goals of preserving the free status of all derivatives of our free software and of promoting the sharing and reuse of software generally. NO WARRANTY 9. 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It is safest to attach them to the start of each source file to most effectively convey the exclusion of warranty; and each file should have at least the "copyright" line and a pointer to where the full notice is found. Copyright (C) 19yy This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 1, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA Also add information on how to contact you by electronic and paper mail. If the program is interactive, make it output a short notice like this when it starts in an interactive mode: Gnomovision version 69, Copyright (C) 19xx name of author Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'. This is free software, and you are welcome to redistribute it under certain conditions; type `show c' for details. The hypothetical commands `show w' and `show c' should show the appropriate parts of the General Public License. Of course, the commands you use may be called something other than `show w' and `show c'; they could even be mouse-clicks or menu items--whatever suits your program. You should also get your employer (if you work as a programmer) or your school, if any, to sign a "copyright disclaimer" for the program, if necessary. Here a sample; alter the names: Yoyodyne, Inc., hereby disclaims all copyright interest in the program `Gnomovision' (a program to direct compilers to make passes at assemblers) written by James Hacker. , 1 April 1989 Ty Coon, President of Vice That's all there is to it! ======================================================================== * LICENSE ======================================================================== This software is licensed under the same terms as Perl5 itself. At the time of writing this means, you can redistribute it and/or modify it under the terms of either: a) the GNU General Public License as published by the Free Software Foundation; either version 1, or (at your option) any later version, or b) the "Artistic License" which both comes with this Kit. This software is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See either the GNU General Public License or the Artistic License for more details.