NAME

Object::Adhoc - make objects without the hassle of defining a class first

SYNOPSIS

 use Object::Adhoc;
 
 my $object = object { name => 'Alice' };
 
 if ($object->has_name) {
   print $object->name, "\n";
 }

DESCRIPTION

Object::Adhoc is designed to be an alternative to returning hashrefs from functions and methods. It's similar to Object::Anon but doesn't do anything special with references or overloading.

Functions

object(\%data, \@keys)

Returns a blessed object built from the given arrayref.

For each key in the list of keys, a getter (name in the SYNOPSIS) and predicate (has_name in the SYNOPSIS) method are created.

Objects are read-only.

Note that Object::Adhoc does not make a clone of %data before blessing it; it is blessed directly.

object(\%data)

If @keys is not supplied, Object::Adhoc will do this:

  @keys = keys(%data);

If there are some keys that will not always be present in your data, passing Object::Adhoc a full list of every possible key is strongly recommended!

make_class(\@keys)

Just makes the class, but doesn't bless a hashref into it. Returns a string which is the name of the class. If called repeatedly with the same keys, will return the same class name.

The class won't have a new method; if you need to create objects, just directly bless hashrefs into it.

It is possible to use this in an @ISA, though that's not really the intention of Object::Adhoc.

  package My::Class {
    use Object::Adhoc qw(make_class);
    our @ISA = make_class[qw/ foo bar baz /];
    sub new {
      my ($class, $data) = (shift, @_);
      bless $data, $class;
    }
    sub foobar {
      my ($self) = (shift);
      $self->foo . $self->bar;
    }
  }

make_class is not exported by default.

Diagnostics

Ambiguous method '%s' is getter, not predicate

Given the following:

  my $object = object {
    name     => 'Alice',
    has_name => 1,
  };

Object::Adhoc doesn't know if you want the has_name method to be a getter for the "has_name" attribute, or a predicate for the "name" attribute. The getter wins, but it will issue a warning.

Key '%s' would be bad method name, not generating methods

You've got a key with a name that cannot be called as a method. For example:

  my $alice = object { 'given name' => 'Alice' };

Perl methods cannot contain spaces, so Object::Adhoc refuses to create the method and gives you a warning. (Technically it is possible to create and call methods containing spaces, but it's fiddly.)

This also happens for a few reserved method names like AUTOLOAD, DESTROY, isa, DOES, can, etc. These have particular meanings in Perl that would conflict with them being used as a getter method.

Usage %s(self)

The methods defined by Object::Adhoc expect to be invoked with a blessed object and no other parameters.

  my $alice = object { 'name' => 'Alice' };
  $alice->name(1234);   # error

This throws an exception rather than just printing a warning.

BUGS

Please report any bugs to http://rt.cpan.org/Dist/Display.html?Queue=Object-Adhoc.

SEE ALSO

Comparison with Similar Modules

Object::Adhoc - requires Exporter::Tiny and uses Class::XSAccessor if installed; read-only accessors; predicate methods; no recursion; no overloading; dies on unknown keys.

Object::Anon only core dependencies; read-only accessors; no predicate methods; recuses into nested hashrefs and arrayrefs; treats coderef values as methods and supports overloading; dies on unknown keys.

Hash::Objectify - requires Class::XSAccessor; read-write accessors; no predicate methods; no recursion; no overloading; dies on unknown keys (or returns undef in lax mode).

Hash::AsObject - only core dependencies; read-write accessors (uses AUTOLOAD, potentially slow); no predicate methods; recurses into nested hashrefs; no overloading; returns undef for unknown keys.

Of the four, Object::Adhoc has the fastest accessors, and Hash::Objectify has the fastest constructors. Object::Anon is the slowest.

I'd recommend Object::Adhoc if you want read-only accessors, or Hash::Objectify if you want read-write accessors. Use Object::Anon only if you need the additional features it supports for overloading, custom methods, and recursive application to nested data structures.

Not Quite So Similar Modules

Object::Result - fairly different idea, but can be used for similar purposes. Requires Perl 5.14, Keyword::Simple, PPI, and Method::Signatures.

AUTHOR

Toby Inkster <tobyink@cpan.org>.

COPYRIGHT AND LICENCE

This software is copyright (c) 2020 by Toby Inkster.

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

DISCLAIMER OF WARRANTIES

THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.