From: Robert Klemme <shortcutter@...>
Date: 2007-05-06T22:25:05+09:00
Subject: Re: how to define a method template

On 06.05.2007 13:14, Robert Dober wrote:
> On 5/6/07, Robert Klemme <shortcutter@googlemail.com> wrote:
>> On 06.05.2007 10:36, Nanyang Zhan wrote:
>> > Forgive me for the nonstandard words. I will describe my problem in
>> > details:
>> > I am doing a rails app, and met a ruby problem.
>> > Inside a model class, I will need to write these codes for "apple"
>> > def apple_attr
>> >  apples.collect {|o| o.name}.join(" ")
>> > end
>> >
>> > def apple_attr=(str)
>> >  @apple = str
>> > end
>> >
>> > def save_apple
>> >  #lots of codes
>> > end
>> >
>> > then banana, cat, dog.. each will have a copy of above codes. They are
>> > the same, except replacing the word "apple" with "banana", "cat",
>> > "dog"....
>> >
>> > I know there is a way to put these code in to a module, then mixin the
>> > module with current class, after that, you just need to call a method
>> > (like setup_methods(:apple); setup_methods(:dog)...), instead of typing
>> > the repeated code.
>> >
>> > Would any one tell me how to do it?
>>
>> Why not create all the methods on the fly?  Like
>>
>> class Foo
>>    def setup_methods(sym)
>>      cl = class <<self;self;end
>>      cl.class_eval do
>>        attr_accessor sym
>>      end
>>      cl.class_eval "def #{sym}_save() puts 'saving #{sym}' end"
>>    end
>> end
> Robert I have understood the setup a little bit differently, was it
> not on the class base that OP wanted his methods?

Maybe.  His statement seems to be a bit contradictory.  First he talks 
about all these methods being there.  Then he mentions some method 
setup_methods which I believe is to create those methods.  But you're 
right, could also be a class method (like attr_accessor).  OP, what do 
you want - Robert's solution or Robert's solution? :-)

Kind regards

	robert