Forum: Ruby Extend an object with module stored

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Andrea R. (Guest)
on 2006-01-31 18:10
I would like extend dynamically an object with one or more Module that I
save into an Hash (I now only this way).

-----------------------------
categorie << Categoria.new('Definizioni Testuali', {:name_module =>
ListaDefinizioni, })
categorie << Categoria.new('Definizioni Testuali', {:name_module =>
ListaDefinizioni, :name_module => ListaDefinizioniEditor})
-----------------------------

Then I have store this information in a YAML file, but when I dump the
hash I lost the info about the module.

-----------------------------
--- !ruby/array:Categorie
- !ruby/object:Categoria
  descrizione: Definizioni Testuali
  estensioni:   # MY HASH
    :name_module: !ruby/object:Module {}
- !ruby/object:Categoria
  descrizione: Definizioni Testuali
  estensioni:   # MY HASH
    :name_module: !ruby/object:Module {}
-----------------------------

So when I try to extend, nothing to do.
This code do not give me errors, but it do not extend my object.

-----------------------------
# @categoria.extension is the hash with the module
@categoria.estensioni.each_value { |estensione| @denotato.send('extend',
estensione) }
-----------------------------

Do you know some tecnique to extend an Object with module stored in YAML
file?
Thanks so much to all for the help.

--Reis
Joel VanderWerf (Guest)
on 2006-01-31 21:12
(Received via mailing list)
Andrea R. wrote:
> Then I have store this information in a YAML file, but when I dump the
>   estensioni:   # MY HASH
> -----------------------------
>
> Do you know some tecnique to extend an Object with module stored in YAML
> file?
> Thanks so much to all for the help.
>
> --Reis
>

I had some code to serialize module and class identities (without any of
their instance variables or class variables, though) with 1.8.2 (see
below) but it seems not to work with 1.8.4. I will take a look at it
later today.


class Module
  def is_complex_yaml?
    false
  end
  def to_yaml( opts = {} )
    YAML::quick_emit( nil, opts ) { |out|
      out << "!ruby/module "
      self.name.to_yaml( :Emitter => out )
    }
  end
end
YAML.add_ruby_type(/^module/) do |type, val|
  subtype, subclass = YAML.read_type_class(type, Module)
  val.split(/::/).inject(Object) { |p, n| p.const_get(n)}
end

class Class
  def to_yaml( opts = {} )
    YAML::quick_emit( nil, opts ) { |out|
      out << "!ruby/class "
      self.name.to_yaml( :Emitter => out )
    }
  end
end
YAML.add_ruby_type(/^class/) do |type, val|
  subtype, subclass = YAML.read_type_class(type, Class)
  val.split(/::/).inject(Object) { |p, n| p.const_get(n)}
end
Eero S. (Guest)
on 2006-01-31 21:19
Andrea R. wrote:
> I would like extend dynamically an object with one or more Module that I
> save into an Hash (I now only this way).
>
> -----------------------------
> categorie << Categoria.new('Definizioni Testuali', {:name_module =>
> ListaDefinizioni, })
> categorie << Categoria.new('Definizioni Testuali', {:name_module =>
> ListaDefinizioni, :name_module => ListaDefinizioniEditor})
> -----------------------------
>
> Then I have store this information in a YAML file, but when I dump the
> hash I lost the info about the module.
>
> < snip YAML />
>
> So when I try to extend, nothing to do.
> This code do not give me errors, but it do not extend my object.
>
> -----------------------------
> # @categoria.extension is the hash with the module
> @categoria.estensioni.each_value { |estensione| @denotato.send('extend',
> estensione) }
> -----------------------------
>
> Do you know some tecnique to extend an Object with module stored in YAML
> file?
> Thanks so much to all for the help.

I assume that the module used may vary from object to
object (otherwise it is not necessary to to serialize
it, of course)?

One simple thing you could do would be to store the
*name* of the module instead of the constant. Then,
after loading the YAML, you can use Module#const_get
to obtain the constant again.

> --Reis


E
Joel VanderWerf (Guest)
on 2006-01-31 21:49
(Received via mailing list)
Joel VanderWerf wrote:
> I had some code to serialize module and class identities (without any of
> their instance variables or class variables, though) with 1.8.2 (see
> below) but it seems not to work with 1.8.4. I will take a look at it
> later today.

Here's a version for 1.8.4. Are you listening, _why, and is there a
chance of putting this in the YAML lib?

----------------------------------
Sample code:
----------------------------------
yy = [Enumerable, Comparable, String, File].to_yaml
puts yy
p YAML.load(yy)

----------------------------------
Output:
----------------------------------
---
- !ruby/module Enumerable
- !ruby/module Comparable
- !ruby/class String
- !ruby/class File
[Enumerable, Comparable, String, File]

----------------------------------
Implementation:
----------------------------------
require 'yaml'

class Module
  yaml_as "tag:ruby.yaml.org,2002:module"

  def Module.yaml_new( klass, tag, val )
    if String === val
      val.split(/::/).inject(Object) {|m, n| m.const_get(n)}
    else
      raise YAML::TypeError, "Invalid Module: " + val.inspect
    end
  end

  def to_yaml( opts = {} )
    YAML::quick_emit( nil, opts ) { |out|
      out.scalar( "tag:ruby.yaml.org,2002:module", self.name, :plain )
    }
  end
end

class Class
  yaml_as "tag:ruby.yaml.org,2002:class"

  def Class.yaml_new( klass, tag, val )
    if String === val
      val.split(/::/).inject(Object) {|m, n| m.const_get(n)}
    else
      raise YAML::TypeError, "Invalid Class: " + val.inspect
    end
  end

  def to_yaml( opts = {} )
    YAML::quick_emit( nil, opts ) { |out|
      out.scalar( "tag:ruby.yaml.org,2002:class", self.name, :plain )
    }
  end
end
Andrea R. (Guest)
on 2006-02-01 17:54
Joel VanderWerf wrote:
> Joel VanderWerf wrote:
>> I had some code to serialize module and class identities (without any of
>> their instance variables or class variables, though) with 1.8.2 (see
>> below) but it seems not to work with 1.8.4. I will take a look at it
>> later today.
>
> Here's a version for 1.8.4. Are you listening, _why, and is there a
> chance of putting this in the YAML lib?
>

I will try in the next days.

> ----------------------------------
> Sample code:
> ----------------------------------
> yy = [Enumerable, Comparable, String, File].to_yaml
> puts yy
> p YAML.load(yy)
>
> ----------------------------------
> Output:
> ----------------------------------
> ---
> - !ruby/module Enumerable
> - !ruby/module Comparable
> - !ruby/class String
> - !ruby/class File
> [Enumerable, Comparable, String, File]

Thanks for the answer.
--Reis
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