From: Robert Klemme <bob.news@...>
Date: 2004-10-22T23:14:13+09:00
Subject: Re: Associating argument descriptions with method


"Gavin Kistner" <gavin@refinery.com> schrieb im Newsbeitrag
news:08B3F283-2430-11D9-A186-000A959CF5AC@refinery.com...
> SUMMARY
> Why does the code at the end return nil for .arguments?
>
> DETAILS
> I'm trying to come up with a system of describing arguments for certain
> public methods, so that my GUI can provide reasonable input widgets and
> constraints. My first idea was to associate this information with each
> method, so that I could discover the public methods and then have each
> method know how to describe itself. However, the following attempt at
> this is leaving me with an empty array.
>
> I'm happy to go another way with this (store the descriptions in an
> instance variable of the class, rather than on each method) but was
> wondering why this doesn't do what I expected.

The reason is most likely, that you always get new instances of
UnboundMethod:

>> def log(o) print o.id, ":", o.inspect, "\n" end
=> nil
>> log String.instance_method( :length )
134619252:#<UnboundMethod: String#length>
=> nil
>> log String.instance_method( :length )
135146692:#<UnboundMethod: String#length>
=> nil
>> log String.instance_method( :length )
135088144:#<UnboundMethod: String#length>
=> nil
>> log String.instance_method( :length )
135066784:#<UnboundMethod: String#length>
=> nil
>> log String.instance_method( :length )
135039148:#<UnboundMethod: String#length>
=> nil
>> log String.instance_method( :length )
135027784:#<UnboundMethod: String#length>
=> nil

Kind regards

    robert