[Asdf-devel] syntax control

[Faré]

I believe that with its massively scaled down functionality and
enhanced configurability,
my syntax-control is ready for merge before the 3.1 release:
* all it does in its default configuration is rebind *readtable* to
the value it had when loading asdf.
 If you require asdf then use load-system without setf'ing *readtable*
 just in between the two in your load script, you're good.
 I don't imagine anyone changing the readtable at that moment,
 because there's no library yet to support or use such readtable modification.

* it allows all kind of configuration hooks, that would then become
available with #+asdf3.1

* It does NOT by default rebind any other variable (in particular, it
does nothing to *read-default-float-format*), since they are not bound
around load or compile-file and thus it might break backward
compatibility somehow to do that. We just saw how controversial this
could be, and even if something were to be done in the future, that
wouldn't be a change to make before the 3.1.1 release.

* I actually removed binding of *read-default-float-format* in parts
of uiop where I was binding it to 'double-float inside a
with-standard-io-syntax. While it would be my preference to generalize
this binding, I have seen from the previous discussion that this
wasn't backward compatible enough.

If you let me merge this branch into master, I'll clean up the code a
bit, by removing some unused functions that I'm otherwise keeping for
experimental purposes in my branch. I can also do any amount of
editing you require before merging. But I believe it is the right
thing to merge at least the *shared-readtable* support and some of the
configuration hooks, if not the system-variables support.

—♯ƒ • François-René ÐVB Rideau •Reflection&Cybernethics• http://fare.tunes.org
(labels(({(] &rest [)(apply([ ])[))([(])(elt(]())]))(](<)(
do-external-symbols(]`:cl)(push`,]`,<))(sort <`string<`:key`string))(}(}
{)({`688({`875({`398()"~{~A ~}~%"(]()))}(+`,{(*)})))({`381)({`816`2/9)))
({`561()#'}`(874,948 7,6009 4862,370 10,12249)`(3,2 4,4 2,1 1,0)))