Re: named-let

[Stefan Monnier <monnier@iro.umontreal.ca>]

>> And we can also use approaches like "inline, together with a check that
>> the function was not advised" for functions which have not been
>> officially declared as inlinable (such checks are already used in the
>> native-comp code, IIRC, tho just to use "fast call" rather than do
>> inlining).
>
> I'm not sure I understand it. Given code like
>
> (defun add1 (b)
>   (+ b 1))
>
> (defun test ()
>   (advice-add (intern "add1") :after (lambda (&rest _)
>                                        (message "Whoa!")))
>   (+ 10 (add1 20)))
>
> We want to inline (add1 20) so the program becomes (+ 10 (+ 1 20)). But
> advice can happened at run time.

The inlining would basically lead to the following code:

    (+ 10 (if (eq (symbol-function 'add1) <thethingweexpect>) (+ 20 1)
              (add1 20)))

which the compiler might be able to optimize to something equivalent to:

    (if (eq (symbol-function 'add1) <thethingweexpect>) 31
        (+ 10 (add1 20)))


-- Stefan