Re: ¬ notation for not? Ref: Add a couple cells to lisp-prettify-symbols-alist

[Stefan Monnier]

> Perhaps doing it how calc manages its units would be satisfactory?  The
> short of it being that `math-standard-units' and user-defined
> `math-additional-units' are used to build `math-units-table'.  Though,
> for units there isn't a need to blacklist, and it sounds like a good
> option to have for prettify-symbols.

Whether the customization specifies what to include or what to exclude,
there is still the issue that specific mappings could be complex
(currently it's only (STRING . CHAR), but it'll likely need to be
extended at some point such that you can additionally specify some
predicate to check that the mapping is valid in a given context, or even
to dynamically decide which mapping to use depending on context).

So the mappings themselves should probably be regarded as "code" rather
than customization, and the customization interface should just let the
user select which mappings to (de)activate.


        Stefan