From: "Ara.T.Howard" <Ara.T.Howard@...>
Date: 2005-10-06T23:35:07+09:00
Subject: Re: foo= ... the only exception to the implicit-self rule ?

On Thu, 6 Oct 2005, Gavin Kistner wrote:

> On Oct 6, 2005, at 1:31 AM, itsme213 wrote:
>> I guess a set_x(val) is the other alternative. Not sure which I dislike 
>> more
>> :-(
>
> I'm amazed that you find either the above or foo(x) more appealing than 
> simply using self.foo = x. In my personal opinion, the assignment is clear, 
> and made clearer by the presence of 'self'.

it's just my opinion, but i think this is clear as a whistle:

   require 'traits'

   class Widget
     traits %w( colour width height style )
   end

   class Button < Widget
     color 'blue'
     width 42
     height 42
     sytle 'swirly'
   end

and this

   require 'traits'

   class C
     traits(TRAITS = %w( a b c d e f ))

     def initialize *args
       TRAITS.each{|t| send t, args.shift}
     end
   end

visually the reader/writer method (writer if given arg) can be very, very nice
on the eyes and fingers - i just takes getting used to, like dropping the ';'
and '$' when moving from perl to ruby.  ;-)

i espcially like that i can do

   def init hash = {}
     hash.each{|k,v| send k, v}
   end

instead of

   def init hash = {}
     hash.each do |k,v|
       meth = "#{ k }="
       send meth, v
     end
   end

which always feels hackish to me


> The only alternative that I would ever (personally) endorse would be some
> sort of sigil for local variables like there is for global, instance, and
> class variables. (Ick, more punctuation. Ick, more typying. Ick, breaks
> backwards compatibility. But: at least it would be consistent with other
> variables.) Something like: %foo = 12  #The randomly-chosen % means local
> variable.  foo = 12  #Method call with implicit self.

i think a symbol for local vars makes a TON of sense and is, really, in
keeping with ruby's design since every other scope is signaled by a symbol.

the rule could be

   foo = 42

   # if method exists foo=, use it
   # else local var

   foo := 42  # force local var

or

   !foo = 42 # force local var
   %foo = 42 # force local var

the thing with local vars is that, if ruby ALSO changed to lookup to search
for methods FIRST, and then to fall back on local you really wouldn't have to
use the local symbol/marker exectp in cases where a local var shadows a
method in the scope of object instance.

> But...really, I'm reasonably happy with the way things are now.

me too.

cheers.


-a
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