From: matz@... (Yukihiro Matsumoto)
Date: 2003-11-20T04:14:47+09:00
Subject: Re: "stereotyping" (was: Re: Strong Typing (Re: Managing metadata about attribute types) )

Hi,

In message "Re: "stereotyping" (was: Re: Strong Typing (Re: Managing metadata about attribute types) )"
    on 03/11/20, "Sean O'Dell" <sean@celsoft.com> writes:

|Listen, I don't mean to be obtuse, but declaring Ruby's flexibility is not a 
|guarantee of flexibility.  It's flexible until a library requires certain 
|methods and parameters.  Then you're stuck.  It's better to get a nice, 
|descriptive message like "your object does not conform to the :memorymap 
|interface" than to get a message that says "in line 45,289 of a file you know 
|nothing about in the middle of a bunch of code you didn't write, a call was 
|made to some object whose name you have to trace to find out where it came 
|from and that call didn't have the right number of parameters.  Figure it out 
|for yourself, bubba."

I don't mean "type checking is bad", but "type checking based on class
inheritance hierarchy is bad", and we don't have any other better type
checking schema in Ruby (yet).

|See what I'm getting at?  Your flexibility is already gone at this point.  I'm 
|not advocating taking away any more.  I'm just advocating a mechanism for 
|reporting these incompatibilities, so when you are hit with this problem, you 
|can very quickly assess what went wrong and make an adjustment.

It's good to have the mechanism like that, I agree, even I put the
feature in my latest slides.  But there's still long way to design and
implement it efficiently, if I am right.

							matz.