From: Konrad Meyer <konrad@...>
Date: 2007-08-10T03:46:43+09:00
Subject: Re: define_method with default parameters

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On Thursday 09 August 2007 11:38:06 am Tom Werner wrote:
> Gordon Thiesfeld wrote:
> > On Aug 9, 11:40 am, Emmanuel Oga <oga_emmanuel_...@yahoo.com.ar>
> > wrote:
> >  =20
> >> how can i use define_method to assign default parameters?
> >>
> >>    =20
> >
> > Not sure if this is the most elegant way, but:
> >
> >   define_method(:method_name) do |*args|
> >     parameter, parameter2 =3D *args
> >     parameter2 ||=3D 'default'
> >     puts parameter
> >     puts parameter2
> >   end
> >
> >
> >  =20
>=20
>=20
> Has the addition of block argument defaults to the language been=20
> considered? There are a number of places (especially in define_method,=20
> Proc.new, and lambda) where it would come in handy. The syntax would of=20
> course be:
>=20
> def foo
>   yield 'from method'
> end
>=20
> foo do |x, y =3D 'from default'|
>   puts x
>   puts y
> end
>=20
> Which would output:
>=20
> from method
> from default
>=20
> I've seen this come up enough that its addition would seem welcome. Are=20
> there arguments against it?
>=20
> Tom

I believe this has come up *lots*. IIRC, the current response is that such
block defaults are not possible with the lexical parser / grammar ruby
currently uses.

=2D-=20
Konrad Meyer <konrad@tylerc.org> http://konrad.sobertillnoon.com/

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