From: walter@...
Date: 2004-07-03T05:02:51+09:00
Subject: Re: define_method to add a Class method?


> On Friday 02 July 2004 12:42, walter@mwsewall.com wrote:
> > How do you use define_method (or an equivalent) to add a method to a
> > Class.
> >
> > I want to create a class from a Database result set at runtime.  I
> > was doing this by building a string and the evaling it, which works,
> > but wasn't all that rubyish and was ugly.
> >
> > I am now using an Anonymous class ie Class.new{...} and everything
> > is great except I can't seem to create a class method this way.
> >
> > I know I am missing something quite obvious, I just can't seem to
> > find it.
> >
> > Any pointers would be greatly appreciated.
> 
> I'd stick with eval; it does the job.  Something like this should work
> just fine:
> 
> class_name = "MyClass"
> code = "print 'Hello, world!\n'"
> method_name = "my_method"
> 
> eval_string = <<-EVAL
>   class #{class_name}
>     def #{method_name}
>       #{code}
>     end
>   end
> EVAL
> 
> eval eval_string
> 
> o = MyClass.new
> o.my_method #=> "Hello, world!\n"
> 
> 
>  Sean O'Dell
> 


That was how original version worked, and I can seem to port 
everything except the creation of the class methods using the 
Class.new{...} syntax.  It just seems as if I am missing something.  
Can we not add a class method using define_method.  I have tried it 
in combination with instance_eval, module_eval, directly on the 
class, within the class, etc but so far no luck.

I guess I just want to know if it can be done using a define_ method 
or do we _have_ to use eval to add a class method this way.


Thanks,


Walt
*****************************************************
Walter Szewelanczyk
IS Director
M.W. Sewall & CO.        email : walter@mwsewall.com     
259 Front St.            Phone : (207) 442-7994 x 128
Bath, ME 04530           Fax   : (207) 443-6284
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