From: John Cowan <[email protected]> Subject: Re: [r6rs-discuss] Import choices: flexibility vs. discoverability Date: Tue, 13 Oct 2009 17:06:26 -0400
> Ray Dillinger scripsit: > > > It is necessary at times to write modules that do things in different > > ways depending on what resources they have available. If some module > > is unavailable, they load some other module and do it a different > > way instead. > > That can be achieved, as I was trying to explain, by loading a shim > module that is always available and includes one of several sets of > code, either the Good Module code or an interface to the Bad Module. > Include is ordinary syntax, so it can be controlled by cond-expand > or a syntax-rules macro. Hmm... in this scenario, you can only say (import Good-Module) within some conditionals, either directly in the cond-expand clause or indirectly within the included file. That means import must be recognized *after* macro expansion, or the conditional must be lifted to the module-syntax level, doesn't it? --shiro _______________________________________________ r6rs-discuss mailing list [email protected] http://lists.r6rs.org/cgi-bin/mailman/listinfo/r6rs-discuss
