On Mon, Jul 29, 2013 at 9:50 PM, rosenfeld (Rodrigo Rose= nfeld Rosas) <rr.rosas@gmail.com> wrote:

Issue #8629 has been updated by rosenfeld (Rodrigo Rosenfeld Rosas).

Ok, thanks for considering. I'll try to think in other approaches to de= al with params bindings to propose to the Rails web framework, but that won= 't be as elegant as having the binding rules extracted directly from th= e default values (since in those cases the default values wouldn't be a= proc if the users read the documentation).

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Feature #8629: Method#parameters should include the default value

https://bugs.ruby-lang.org/issues/8629#change-40750

Author: rosenfeld (Rodrigo Rosenfeld Rosas)

Status: Rejected

Priority: Normal
Assignee: matz (Yukihiro Matsumoto)
Category: core
Target version:

def a_method arg1=3D1, now =3D Time.now, arg2 =3D arg1 + 1
end

method(:a_method).parameters =3D=3D [[:opt, :arg1], [:opt, :now], [:opt, :a= rg2]]

I'd prefer if it could return [[:opt, :arg1, 1], [:opt, :now, now_proc]= , [:opt, :arg2, arg2_proc]], and expect now_proc[] to be the current time a= nd arg2_proc[] to raise an exception since arg1 is not defined.

Rationale:

Ruby doesn't support optional typing such as:

def a_method Date date, Integer n =3D 0, String name =3D ''
end

Groovy does, and this allows Grails to perform some interesting stuff, like= params binding in controller methods.

If Ruby allowed the default values to be introspected, web frameworks would= be able to achieve a similar binding feature. For example, they could use = the default to decide upon how to bind the param. They could use the defaul= t_value.class or if the default value is nil it could be specified by provi= ding the class itself. For instance:

def an_action name: '', parent_name: String, age: Integer, date: Da= te.today
end

Of course, you'd need to set up the framework so that it knows how you = intend parse dates and other special types from string, but this could make= the developer life easier and safer against this kind of attack (like tryi= ng to instantiate a hash, etc).

An alternative would be something like:

def an_action params =3D {name: :string, age: :integer, date: :date}
end

You get the idea. Many APIs would be possible to be built if we're able= to easily get access to the default values when inspecting a method.

Could you please consider this idea?

--
http://bugs.ruby-l= ang.org/

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=

Akira Matsuda&l= t;ronnie@dio.jp><= /div>

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