"Tobias C. Rittweiler" tcr@freebits.de writes:

szergling senatorzergling@gmail.com writes:

...

Hi folks,

Perhaps I've confused myself a bit here, but there seem to be something wrong with either Slime (most likely), SBCL threads, or my understanding of the difference between (funcall 'print-something) and (funcall #'print-something).

Could someone confirm the following behaviour?

This is not a Slime issue; the analysis seems correct, though. You shouldn't rely on this behaviour programmatically. HTH.

I say it's a misunderstanding of the difference between the two funcall examples. You can rely on

(let ((that-which-i-want-to-call 'print-something)) (funcall that-which-i-want-to-call))

and

(let ((that-which-i-want-to-call #'print-something)) (funcall that-which-i-want-to-call))

to have different semantics. This is not a bug.

funcall takes a function designator, which can be a symbol or a function. If funcall is called with 'print-something, it picks up the function that that is currently residing in print-something's function cell. But a redefinition of print-something (which is just storing a new value in that symbol's function cell) doesn't magically hunt down and overwrite every function object (now not bound to any symbol's function attribute) that happened to have been stored in print-something's function cell at some point in the past. So, in the second example the same function will be called, no matter in what way print-something is manhandled in another thread.

Cheers,

Rudi