# NAME

Hash::Convert - Rule based Hash converter.

# SYNOPSIS

   #!/usr/bin/env perl
   use strict;
   use warnings;
   use Hash::Convert;

   my $rules = {
       visit   => { from => 'created_at' },
       count   => { from => 'count', via => sub { $_[0] + 1 }, default => 1 },
       visitor => {
           contain => {
               name => { from => 'name' },
               mail => { from => 'mail' },
           },
           default => {
               name => 'anonymous',
               mail => 'anonymous',
           }
       },
       price => {
           from => [qw/item.cost item.discount/],
           via => sub {
               my $cost     = $_[0];
               my $discount = $_[1];
               return $cost * ( (100 - $discount) * 0.01 );
           },
       },
   };
   my $opts = { pass => 'locate' };

   my $converter = Hash::Convert->new($rules, $opts);

   my $before = {
       created_at => time,
       count      => 1,
       name       => 'hixi',
       mail       => '[email protected]',
       locate     => 'JP',
       item => {
           name     => 'chocolate',
           cost     => 100,
           discount => 10,
       },
   };
   my $after = $converter->convert($before);
   print Dumper $after;
   #{
   #    'visitor' => {
   #        'mail' => '[email protected]',
   #        'name' => 'hixi'
   #    },
   #    'count' => 2,
   #    'visit' => '1377019766',
   #    'price' => 90,
   #    'locate' => 'JP'
   #}

# DESCRIPTION

Hash::Convert is can define hash converter based on the rules.

# Function

## convert

Convert hash structure from before value.

   my $rules = {
       mail => { from => 'email' }
   };
   my $converter = Hash::Convert->new($rules);
   my $before = { email => '[email protected]' };
   my $after  = $converter->convert($before);
   #{
   #  mail => '[email protected]',
   #}

# Rules

## Command

- from

       my $rules = { visit => { from => 'created_at' } };
       #(
       #(exists $before->{created_at})?
       #    (visit => $before->{created_at}): (),
       #)
- from + via

   \`via\` add after method toward \`from\`.
   \`via\` can receive multiple args from \`from\`.

   Single args

       my $rules = { version => { from => 'version', via => sub { $_[0] + 1 } } };
       #(
       #(exists $before->{version})?
       #    (version => sub {
       #        $_[0] + 1;
       #    }->($before->{version})): (),
       #)

   Multi args

       my $rules = { price => {
           from => [qw/cost discount/],
           via => sub {
               my $cost     = $_[0];
               my $discount = $_[1];
               return $cost * (100 - $discount);
       }};
       #(
       #(exists $before->{item}->{cost} && exists $before->{item}->{discount})?
       #    (price => sub {
       #        my $cost = $_[0];
       #        my $discount = $_[1];
       #        return $cost * (100 - $discount);
       #    }->($before->{item}->{cost}, $before->{item}->{discount})): (),
       #)

- contain

       my $rules = { visitor => {
           contain => {
               name => { from => 'name' },
               mail => { from => 'mail' },
           }
       }};
       #(
       #(exists $before->{name} && exists $before->{mail})?
       #    (visitor => {
       #    (exists $before->{mail})?
       #        (mail => $before->{mail}): (),
       #    (exists $before->{name})?
       #        (name => $before->{name}): (),
       #    }): (),
       #)

## Others expression

- default

   default can add all command (\`from\`, \`from\`+\`via\`, \`contain\`) .

       my $rules = { visitor => {
           contain => {
               name => { from => 'name' },
               mail => { from => 'mail' },
           },
           default => {
               name => 'anonymous',
               mail => 'anonymous',
           }
       }};
       #(
       #(visitor => {
       #(exists $before->{mail})?
       #    (mail => $before->{mail}): (),
       #(exists $before->{name})?
       #    (name => $before->{name}): (),
       #}):
       #(visitor => {
       #  'name' => 'anonymous',
       #  'mail' => 'anonymous'
       #}),
       #)

- dot notation

   \`dot notation\` make available nested hash structure.

       my $rules = { price => {
           from => [qw/item.cost item.discount/],
           via => sub {
               my $cost     = $_[0];
               my $discount = $_[1];
               return $cost * ( (100 - $discount) * 0.01 );
           },
       }};
       #(
       #(exists $before->{item}->{cost} && exists $before->{item}->{discount})?
       #    (price => sub {
       #        my $cost = $_[0];
       #        my $discount = $_[1];
       #        return $cost * ( (100 - $discount) * 0.01 );
       #    }->($before->{item}->{cost}, $before->{item}->{discount})): (),
       #)



# LICENSE

Copyright (C) Hiroyoshi Houchi.

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

# AUTHOR

Hiroyoshi Houchi <[email protected]>

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