From: Jan Svitok <jan.svitok@...>
Date: 2006-10-18T22:16:02+09:00
Subject: Re: Struct (not) accepting attributes

On 10/18/06, Robert Klemme <shortcutter@googlemail.com> wrote:
> On 18.10.2006 14:33, Kero wrote:
> >> Sum = Struct.new(:bla, :"sum(value)")
> >> sum = Sum.new(2, 5)
> > => #<struct Sum bla=2, :"sum(value)"=5>
> >> sum.send(:"sum(value)")
> > NoMethodError: undefined method `sum(value)' for #<struct Sum bla=2, :"sum(value)"=5>
> >> class X
> >>   attr_accessor :"sum(value)"
> >> end
> > NameError: invalid attribute name `sum(value)'
> >> class Sum
> >>   define_method(:"sum(value)") { "summum!" }
> >> end
> > => #<Proc:0xa7c5f218@(irb):181>
> >> sum.send(:"sum(value)")
> > => "summum!"
> >
> > Not sure this is an error in ruby (1.8.5) or a misunderstanding from me (about Struct).
>
> There is another option: a misunderstanding on your side which attribute
> names can be used in this situation / generally.  As you see your sample
> class X does not work either.
>
> Why don't you just use "sum_value" as attribute name?
>
> Kind regards
>
>         robert

sum(value) is not a valid method name. method names must match (I
believe) /[a-z_][a-zA-z0-9_]+[?!]?/

if you want to have a struct with additional method do this:

class Sum < Struct.new(:blah)
  def sum(value)
   ...
  end
end