From: Ryan Leavengood <mrcode@...>
Date: 2001-10-27T03:04:13+09:00
Subject: [ruby-talk:23483] RE:  Capture undefined method calls?

I believe the method you want is method_missing:

$ ri method_missing
-------------------------------------------------- Object#method_missing
     obj.method_missing( aSymbol [, *args] ) -> anObject
------------------------------------------------------------------------
     Invoked by Ruby when obj is sent a message it cannot handle.
     aSymbol is the symbol for the method called, and args are any
     arguments that were passed to it. The example below creates a class
     Roman, which responds to methods with names consisting of roman
     numerals, returning the corresponding integer values.

        class Roman
          def romanToInt(str)
            # ...
          end
          def method_missing(methId)
            str = methId.id2name
            romanToInt(str)
          end
        end
        r = Roman.new
        r.iv      #=> 4
        r.xxiii   #=> 23
        r.mm      #=> 2000


Ryan Leavengood (finally back on the mailing list)

> -----Original Message-----
> From: Morris, Chris [mailto:chris.morris@snelling.com]
> Sent: Friday, October 26, 2001 1:57 PM
> To: ruby-talk ML
> Subject: [ruby-talk:23481] Capture undefined method calls?
> 
> I've got the following line:
> 
>   document.form.ObjectID.value = 'x'
> 
> form currently is an html dom node. What I'd like to do is something
like
> (psuedo code falling out all over the place):
> 
>   def form
>     # return a wrapper for the node
>     NodeWrapper.new(document.form)
>   end
> 
>   class NodeWrapper
>     def initialize(node)
>       @node = node
>     end
> 
>     def someSortOfCatchAllForUndefinedCalls(*args)
>       propName = nameOfUndefinedMethod # e.g. ObjectID
>       if @node.hasProperty(propName)
>         @node.propName.value = args[0]
>       else
>         assert(false, 'property does not exist')
>       end
>     end
>   end
> 
> then I could simplify the initial call to:
> 
>   form.ObjectID = 'x' # maybe, haven't accounted for = sign
> 
> ... and get some additional testing code. Hmmm, well I'm not sure if
this
> would be that useful to me now that I've thought it through, but I'm
still
> curious if Ruby can do this sort of thing ... it seems like it could.
> 
> Chris