From: Florian Gross <flgr@...>
Date: 2005-01-26T05:45:48+09:00
Subject: Re: "Duck Typing" or "No need for abstract classes"

Nicholas Van Weerdenburg wrote:

> This is the impression I've gotten- that a live image system uses the
> objects that exist while programming against a live system to do code
> completion, etc. In effect, this is what irb completion does.

Partially, IRB does not actually evaluate the expressions. If it sees 
that you are calling a method it will IIRC just list all methods that 
are provided by any of the currently loaded classes. This is a good 
thing for expressions with side effects such as `rm -rf /`, but could be 
improved in other cases.

> Interestingly, Rails seems to be evolving into a pseudo-image-like
> system, with class reloads and breakpoints that spawn irb sessions.
> Conceivably an editor could be smart enough to bind to the running
> environment.

As the author of the breakpoint library I'm still very interested in 
using it for writing an IDE that will attach to a live code base and 
allow you to investigate, modify and much more. Note that this would at 
first not be just as nifty as the Smalltalk solutions because you can 
not generally get code for methods and so on, but using some of the cool 
thing like the AST library or by reading back the code from Files you 
could probably get pretty close.

It's an interesting area and I'd be willing to offer as much support as 
I can to such efforts if somebody can kick this off with a decent code base.