NAME
    Dist::Zilla::Plugin::Rinci::Validate - Insert argument validator code in
    output code

VERSION
    version 0.07

SYNOPSIS
    In dist.ini:

     [Rinci::Validate]

    In your module:

     $SPEC{foo} = {
         args => {
             arg1 => { schema => ['int*', default=>3] },
             arg2 => { },
         },
     };
     sub foo {
         my %args = @_;

         my $arg1 = $args{arg1}; # VALIDATE_ARG
         ...
     }

    output will be something like:

     $SPEC{foo} = {
         args => {
             arg1 => { schema => ['int*', default=>3] },
             arg2 => { },
         },
     };
     sub foo {
         my %args = @_;

         my $arg1 = $args{arg1}; require Scalar::Util; my $arg_err; (($arg1 //= 3), 1) && ((defined($arg1)) ? 1 : (($err_arg1 = 'TMPERRMSG: required data not specified'),0)) && ((Scalar::Util::looks_like_number($arg1) =~ /^(?:1|2|9|10|4352)$/) ? 1 : (($err_arg1 = 'TMPERRMSG: type check failed'),0)); return [400, "Invalid value for arg1: $err_arg1"] if $arg1; # VALIDATE_ARG
         ...
     }

    You can also validate all arguments:

     sub foo {
         my %args = @_; # VALIDATE_ARGS

         ...
     }

DESCRIPTION
    This plugin inserts argument validation code into your module source
    code, at location marked with "# VALIDATE_ARG" or "# VALIDATE_ARGS".
    Validation code is compiled using "Data::Sah" from Sah schemas specified
    in "args" property in "Rinci" function metadata in the module.

  USAGE
    To validate a single argument, in your module:

     sub foo {
         my %args = @_;
         my $arg1 = $args{arg1}; # VALIDATE_ARG

    The significant part that is interpreted by this module is "my $arg1".
    Argument name is taken from the lexical variable's name (in this case,
    "arg1"). Argument must be defined in the "args" property of the function
    metadata. If argument name is different from lexical variable name, then
    you need to say:

     my $f = $args->{frobnicate}; # VALIDATE_ARG frobnicate

    To validate all arguments of the subroutine, you can say:

     sub foo {
         my %args = @_; # VALIDATE_ARGS

    There should only be one VALIDATE_ARGS per subroutine.

    If you use this plugin, and you plan to wrap your functions too using
    Perinci::Sub::Wrapper (or through Perinci::Access, Perinci::CmdLine,
    etc), you might also want to put "_perinci.sub.wrapper.validate_args =>
    0" attribute into your function metadata, to instruct
    Perinci::Sub::Wrapper to skip generating argument validation code when
    your function is wrapped, as argument validation is already done by the
    generated code.

    If there is an unvalidated argument, this plugin will emit a warning
    notice. To skip validating an argument (silence the warning), you can
    use:

     sub foo {
         my %args = @_;
         my $arg1 = $args{arg1}; # NO_VALIDATE_ARG

    or:

     sub foo {
         # NO_VALIDATE_ARGS

FAQ
  Rationale for this plugin?
    This plugin is an alternative to Perinci::Sub::Wrapper, at least when it
    comes to validating arguments. Perinci::Sub::Wrapper can also generate
    argument validation code (among other things), but it is done during
    runtime and can add to startup overhead (compiling complex schemas for
    several subroutines can take up to 100ms or more, on my laptop). Using
    this plugin, argument validation code is generated during building of
    your distribution.

    Using this plugin also makes sure that argument is validated whether
    your subroutine is wrapped or not. Using this plugin also avoids
    wrapping and adding nest level, if that is not to your liking.

    Instead of using this plugin, you can use wrapping either by using
    Perinci::Exporter or by calling Perinci::Sub::Wrapper's "wrap_sub"
    directly.

  But why use Rinci metadata or Sah schema?
    In short, adding Rinci metadata to your subroutines allows various tools
    to do useful stuffs, relieving you from doing those stuffs manually.
    Using Sah schema allows you to write validation code succintly, and
    gives you the ability to automatically generate Perl/JavaScript/error
    messages from the schema.

    See their respective documentation for more details.

  But the generated code looks ugly!
    Admittedly, yes. Validation source code is formatted as a single long
    line to avoid modifying line numbers, which is desirable when debugging
    your modules. An option to not compress everything as a single line
    might be added in the future.

TODO
    *   Use PPI instead of fragile regex.

    *   Option to not compress validator code to a single line.

    *   Option to configure variable name to store validation ($arg_err).

    *   Option to reuse code for the same schema.

AUTHOR
    Steven Haryanto <stevenharyanto@gmail.com>

COPYRIGHT AND LICENSE
    This software is copyright (c) 2013 by Steven Haryanto.

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

