Re: Proper namespaces in Elisp

[Daniel Colascione]

On 5/7/20 1:28 PM, Stefan Monnier wrote:
> > I don't like reader magic. It complicates code logic. I know we talked about
> > symbol-macrolet and macrolet as possible options and know why neither is
> > quite the right thing, but I still think that a macro of the same general
> > kind would work fine. Macros don't need to recognize defining forms if they
> > macroexpand their bodies before walking them.
>
> You need not only discover the defining forms but also the "using"
> forms.  So you need to know that the arguments to `make-local-variable`,
> `add-hook`, `symbol-value`, `facep`, ... (and all function that pass
> their arg to one of those) are not just random symbols (that you should
> leave untouched) but symbols that obey the namespace rules.

I think these situations are rare enough that we can ask people to pass 
fully-qualified symbols.

> In Common Lisp, the distinction is made by using keywords instead of
> normal symbols when the namespace rules shouldn't apply, but Elisp
> doesn't have such a tradition.

Common Lisp does deal with this problem in some cases, e.g., in LOOP. We 
should be moving forwards keywords anyway.

FWIW, I think elisp should just literally copy Common Lisp's approach. 
It's tried and tested, and the pitfalls are well-understood. It'll take 
a while to work the kinks out of a bespoke approach, and the CL approach 
seems adequate for addressing the problem that people are trying to solve.