[MacRuby-devel] re-implemention of attr_accessor and valueForKey:

[kyossi]

Hi,

Thanks for ticket and simplify the code.
For a while I'll use class_eval to define a method which require KVC compliant.


2011/3/11 Thibault Martin-Lagardette <thibault.ml at gmail.com>:
> Hi,
> After fiddling a little bit with the code, I could not find the exact issue,
> but could reduce the code a lot.
> For the sake of it, I opened a Trac ticket with the reduced
> code: https://www.macruby.org/trac/ticket/1188
> Cheers,
> --
> Thibault Martin-Lagardette
>
> On Thursday, March 10, 2011 at 13:59, kyossi wrote:
>
> Hi,
>
> I'm plan to add some functionality to existing attr_accessor.
> I've started with re-implement attr_accessor with same functionality,
> but when I implement it by define_method, it failed with Segmentation
> fault when I call valueForKey(:key).
>
> Am i doing wrong with class Base2??,
>
> The Code is
>
> #utility
> class String
> #upcase first char. "foo".upcaseFirstChar => "Foo"
> def upcaseFirstChar
> self[0].upcase + self[-self.size+1, self.size-1]
> end
> end
>
> #implement of my_attr_accessor with evaluate string. works fine
> class Base
> def self.my_attr_accessor(sym)
> class_eval %{
> def #{sym}
> @#{sym}
> end
>
> def set#{sym.to_s.upcaseFirstChar}(val)
> @#{sym} = val
> end
> }}
> end
> end
>
> class MyClass < Base
> my_attr_accessor :foo
> end
>
>
> obj = MyClass.new
> obj.setFoo(3)
> p obj.foo #=>3
> p obj.valueForKey(:foo) #=>3
>
> #another implement of my_attr_accessor
> class Base2
> def self.my_attr_accessor(sym)
> define_method(sym) do
> instance__variable_get("@#{sym}")
> end
>
> define_method("set#{sym.to_s.upcaseFirstChar}") do |val|
> instance_variable_set("@#{sym}", val)
> end
> end
> end
>
> class MyClass2 < Base2
> my_attr_accessor :foo
> end
>
> obj2 = MyClass2.new
> obj2.setFoo(7)
> p obj2.foo #=>7
> p obj2.valueForKey(:foo) #=> Segmentation fault
>
>
> =====================
> $ macruby my_attr_accessor.rb
> 3
> 3
> 7
> Segmentation fault
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