RE: `read--expression' and `read-minibuffer'

[Drew Adams <drew.adams@oracle.com>]

> > Well, sure, there are Lisp objects (e.g. byte-compiled
> > functions) that are not readable expressions.  But those are
> > not readable anyway, AFAIK.
> 
> Lists of symbols are Lisp object, are perfectly readable, but shouldn't
> use `read--expression'.

I don't see why not.

> `read--expression' is to read the subset of
> S-exps which represent an Elisp expression (something that would be
> meaningful to pass to `eval', for example).

I don't see why you think that what it reads is limited, or could
or should be limited, to expressions that can be eval'd.

(read--expression "Expression: ")
(1 2 frou frou)

=> (1 2 frou frou)

> > Why isn't `read--expression' treated as a user function, like
> > `read-minibuffer', instead of being considered "internal"?
> 
> Can't remember the details, but I think it's because it's easier to make
> it "external" than the reverse.

How about making it external now?  It is a useful general-purpose
function.

> > And `read-minibuffer' is still used for `interactive' with
> > spec "x".  Why isn't `read--expression' used for that now?
> 
> Not sure either.  Probably just a conservative choice.

Maybe consider it?  I don't see any risk.  The main difference
is that it uses a more useful keymap for reading expressions.