SYNOPSIS

    In dist.ini:

     [Rinci::Wrap]
     ; optional, will be eval'ed as Perl code and passed to wrap_sub()
     wrap_args = { validate_result => 0, convert => {retry=>2} }
     ; optional, will not squish code and add marker comment
     debug=1

    In your module:

     $SPEC{foo} = {
         v => 1.1,
         args => {
             arg1 => { schema => ['int*', default=>3] },
             arg2 => { },
         },
     };
     sub foo {
         my %args = @_;
    
         ... your code
         return [200, "OK", "some result"];
     }

    output will be something like:

     $SPEC{foo} = {
         v => 1.1,
         args => {
             arg1 => { schema => ['int*', default=>3] },
             arg2 => { },
         },
     };
     require Scalar::Util; require Data::Dumper; { my $meta = $SPEC{foo}; $meta->{args}{arg1}{schema} = ["int", {req=>1, default=>3}, {}]; } # WRAP_PRESUB
     sub foo {
         my %args = @_;
    
         ... generated preamble code
    
         ... your code
         return [200, "OK", "some result"];
    
         ... generated postamble code
     }

DESCRIPTION

    This plugin inserts code generated by Perinci::Sub::Wrapper to your
    source code during building. This lets you add functionalities like
    argument validation, result validation, automatic retries, conversion
    of argument passing style, currying, and so on.

    Code is inserted in three places (see the above example in Synopsis):

      * The first part (which is the part to load required modules and to
      modify function metadata, e.g. normalize Sah schemas, etc) will be
      inserted right before the opening of the subroutine (sub NAME {).

      * The second part (which is the part to validate arguments and do
      stuffs before performing the function) will be inserted at the start
      of subroutine body after the my %args = @_; (or my $args = $_[0] //
      {}; if you accept arguments from a hashref, or my @args = @_; if you
      accept arguments from an array, or my $args = $_[0] // []; if you
      accept arguments from an arrayref) statement. This should be one of
      the first things you write after your sub declaration before you do
      anything else.

      * The third part (which is the part to validate function result and
      do stuffs after performing the function) will be inserted right
      before the closing of the subroutine.

    Currently regexes are used to parse the code so things might be rather
    fragile.

RESTRICTIONS

    There are some restrictions (hopefully not actually restricting) when
    writing your code if you want to use this plugin.

      * Clash of variables

      The generated wrapper code will declare some variables. You need to
      make sure that the variables do not clash. This is rather simple: the
      variables used by the wrapper code will all be prefixed with _w_
      (e.g. $_w_res) or _sahv_ for variables generated by the Sah schema
      compiler (e.g. $_sahv_dpath).

      * Variable used to accept arguments

      Currently the wrapper internally will perform argument validation on
      $args{ARGNAME} variables, even if you accept arguments from a
      hashref/array/arrayref. Thus:

      If you accept arguments from a hash (the default), you need to put
      the arguments to %args, i.e.:

       my %args = @_;

      You can then get the validated arguments e.g.:

       my $name = $args{name};
       my $addr = $args{address};
       ...

      If you accept arguments from a hashref (i.e. func({ arg1=>1, arg2=>2
      })):

       my $args = $_[0] // {};

      If you accept arguments from an array (e.g. func(1, 2):

       my @args = @_;

      If you accept arguments from an arrayref func([1, 2]):

       my $args = $_[0] // [];

FAQ

 Rationale for this plugin?

    This plugin is an alternative to using Perinci::Sub::Wrapper (PSW)
    dynamically. During build, you generate the wrapper code and insert it
    to the target code. The result is lower startup overhead (no need to
    generate the wrapper code during runtime) and better guarantee that
    your wrapping code (argument validation, etc) is always called when
    your subroutines are called, even if your users do not use PSW and call
    your subroutines directly.

    Another advantage/characteristic using this plugin is that, the wrapper
    code does not introduce extra call level.

 But why use PSW at all?

    In short, adding Rinci metadata to your subroutines allows various
    tools to do useful stuffs, relieving you from coding 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.

    PSW is one of the ways (currently the only way) to implement those
    behaviours/functionalities.

 But the generated code looks ugly!

    Admittedly, yes. Wrapper-generated code is formatted as a single long
    line to avoid modifying line numbers, which is desirable when debugging
    your modules. If you don't want to compress everything as a single
    line, add debug=1 in your dist.ini.

 How do I customize wrapping for my function

    Two ways. You can either use wrap_args in dist.ini (see Synopsis) or
    add an attribute in your function metadata:

     "x.dist.zilla.plugin.rinci.wrap.wrap_args" => { validate_args => 0 },

    which will be merged and will override wrap_args keys specified in
    dist.ini.

