NAME
    Params::Smart - use both positional and named arguments in a subroutine

REQUIREMENTS
    The following non-core modules are required:

      Regexp::Common

INSTALLATION
    Installation can be done using the traditional Makefile.PL or the newer
    Build.PL methods.

    Using Makefile.PL:

      perl Makefile.PL
      make test
      make install

    (On Windows platforms you should use `nmake' instead.)

    Using Build.PL (if you have Module::Build installed):

      perl Build.PL
      perl Build test
      perl Build install

SYNOPSIS
      use Params::Smart 0.04;

      sub my_sub {
        %args = Params(qw( foo bar ?bo ?baz ))->args(@_);
        ...
      }

      my_sub( foo=> 1, bar=>2, bo=>3 );  # call with named arguments

      my_sub(1, 2, 3);                   # same, with positional args

DESCRIPTION
    This module provides "smart" parameter handling for subroutines without
    having to use a changed syntax or source filters. Features include:

    *   Mixed use of named and positional parameters.

    *   Type checking and coercion through callbacks.

    *   Dyanmic parameters configured from callbacks.

    *   Memoization of parameter templates.

  Compatability with Previous Versions

    Note that the formatting for simple parameter templates has changed
    since version 0.03, and the complex parameter templates were not
    implemented until version 0.04, so it is best to specify a minimum
    version in use statements

      use Params::Smart 0.04;

REVISION HISTORY
    A brief list of changes since the previous release:

    0.08  Wed Mar 21 2007
            - added case where undef value used in positional parameter
                  (thanks to Rick Westerman)
            - minor reorganization of POD

    For a detailed history see the Changes file included in this
    distribution.

CAVEATS
    Because Perl5 treats hashes as lists, this module attempts to interpret
    the arguments as a hash of named parameters first. If some hash keys
    match, and some do not, then it assumes there has been an error. If no
    keys match, then it assumes that it the arguments are positional.

    In theory one can pass positional arguments where every other argument
    matches a hash key, or one can pass a hash with the wrong keys (possible
    if one copies/pastes code from the wrong call) and so it is treated as a
    positional argument.

    This is probably uncommon for most data, but subroutines should take
    extra care to check if values are within allowed ranges. There may even
    be security issues if users can blindly specify data that they know can
    cause this confusion. If the application is critical enough, then this
    may not be an appropriate module to use (at least not until the ability
    to distinguish between lists and hashes is improved).

    To diagnose potential bugs, or to enforce named or positional calling
    one can check the _named parameter.

    A future version might make use of Perl internals to get around this
    problem.

SEE ALSO
    This module is superficially similar in function to Getargs::Mixed but
    does not require named parameters to have an initial dash ('-').

    Class::NamedParams provides a framework for implementing named
    parameters in classes.

    Sub::NamedParams will create a named-parameter wrapper around
    subroutines which use positional parameters.

    The syntax of the parameter templates is inspired by Perl6::Subs, though
    not necessarily compatible. (See also *Apocalypse 6* in Perl6::Bible).

    Sub::Usage inspired the error-messages returned by calls to arg().

    Params::Validate is useful for (additional) parameter validation beyond
    what this module is capable of.

    Class::ParmList provides a framework for parameter validation as well.

AUTHOR
    Robert Rothenberg <rrwo at cpan.org>

  Suggestions and Bug Reporting

    Feedback is always welcome. Please use the CPAN Request Tracker at
    http://rt.cpan.org to submit bug reports.

LICENSE
    Copyright (c) 2005-2007 Robert Rothenberg. All rights reserved. This
    program is free software; you can redistribute it and/or modify it under
    the same terms as Perl itself.