Re: Change of Lisp syntax for "fancy" quotes in Emacs 27?

[Garreau\, Alexandre]

On 2018-10-06 at 14:57, Drew Adams wrote:
> My point was only that use of `foo foo' (with a no-break
> space between the two foo's) as a mistake/typo for an
> intended `foo foo' (with a normal space) should not be
> signaled by Lisp as an error. But the no-break space could
> be highlighted as sometimes helpful info. `foo foo' (with
> no-break space) is just a symbol, for Lisp - not a syntax
> error.

Unbreakable space is already colored as some sort of colored underscore.
The problem is there are a bunch of other kind of spaces, though I
personally only use unbreakable, non-justifying and/or “fine” (dunno if
it match an en space) space in French, though I do it commonly in
strings with emacs (which only correctly highlight the normal
unbreakable space, but not the others).  I’d like to see these
highlighted (perhaps, or even preferably, a different way) as well, or
should it be something customizable according user preferences (or
language?).

> E.g. (changing the example):
>
> (let (foo foo)...) binds symbol `foo foo' (with a no-break
> space) to nil. It doesn't bind symbol `foo' to the current
> value of symbol `foo'.

I would have expected it to bind twice foo to nil (or to signal an error
or a warning), yet it seems you used a normal space, unbreakable-space
already highlights in emacs, so I’d noticed it.