Re: lexical-binding is turned on in more use cases

[Alan Mackenzie <acm@muc.de>]

Hello, Stefan.

On Tue, Mar 10, 2020 at 16:41:43 -0400, Stefan Monnier wrote:
> > What specific real problem does forcing M-: to use lexical binding solve?

> Make it behave the way coders who use lexical-binding (which I believe
> are now the majority) expect.

So, you admit there is no specific problem solved by forcing lexical
binding in M-:?

Lexical binding is useless for M-:.  It can't do anything useful.
Unless (contrived example) somebody is going to type in the code for
creating a closure into the minibuffer.  Or something like that.  Is
this really why you want to force lexical-binding in M-:?

I would think that ALL emacs coders, whether working with
lexical-binding nil or t, would expect to be able to bind a dynamic
variable, any dynamic variable, in a let form in M-:

> You likely won't write code that relies on lexical scoping since you're
> used to writing dynamically scoped code, but many coders nowadays never
> touch dynamically scoped code and hence very much expect the lexical
> binding rules, which is mostly the ability to use closures (which is
> sometimes present only implicitly via macros like `gv-ref` (itself used
> in other macros like `add-function`), thunk.el and generator.el macros,
> ...).

So, what we need here is a customisation variable, so that people who
want lexical binding in M-: can have it, and those who want dynamic
binding can also have that.  Agreed?

I'll code it up.

>         Stefan

-- 
Alan Mackenzie (Nuremberg, Germany).