Re: kawa module experience?

[Felix Klock <felix_klock_ii at mac dot com>]

Dominque-

On Dec 1, 2005, at 6:57 PM, Dominique Boucher wrote:
> 2. Regarding the proposed library facility, I do not see problems  
> with the
> proposed approach per se. The only missing part (maybe I have not  
> read the
> SRFI carefully enough) is the ability to "include" source code from  
> another
> file. This could solve many problems w.r.t. interactive/incremental
> development.
>
> The usual problem with libraries is that exported bindings cannot  
> be mutated
> outside the library/module itself. This severely limits our ability to
> change the definition of a function interactively. You have to  
> modify the
> library and reload it, usually loosing all state information  
> (sometimes,
> libraries are stateful), making debugging a nightmare.

There are work-arounds for this problem that are actually pretty  
straight-forward, for a sufficiently expressive macro/module system.

In particular, MzScheme does not allow you to SET! identifiers  
provided via a module, *unless* the module developer plans ahead to  
provide such functionality.  But the developer can take advantage of  
set!-transformers in the macro system to get the desired effect.

For discussion (in the context of MzScheme), see the following:

http://schemecookbook.org/view/Cookbook/ProvidingSetBangableIds

(I do believe there are reasons to have an INCLUDE facility.  But I  
think there are better ways to get the effect you desire, such as the  
one described at the schemecookbook entry above.)

-Felix