[slime-devel] Daily ChangeLog diff

[Helmut Eller]

* Paulo Madeira [2011-11-22 13:46] writes:

> Could frame-package's default implementation be (eval-in-frame
> 'cl:*package* frame-number)?

Hmm... yes, but I'm not sure in what cases that would be better than
what we do know.  Currently we return nil by default.  That way we can
at least tell that the backend has no strong opinion on the matter and
we simply use the current value of *package* as fallback.

The purpose of frame-package was primarily that we can read the names of
local variables without package prefix.  That package is actually more a
(static) property of the frame's function than a (dynamic) property of
the stack frame itself.  Basically we are interested in the package that
was current when the function was compiled.  

In many implementations (eval-in-frame '*package* <N>) is literally the
same as (eval '*package*).  In Lisps that actually bother to reconstruct
the dynamic environment of the time of the call it's also not
necessarily the same package as it was when the function was
read/compiled.

(eval-in-frame '*package* <N>) seems to be as good/bad as the current
default but I haven't actually tried it.

Helmut