[alexandria-devel] ensure-functionf

[Tobias C. Rittweiler]

"Knut Olav Bøhmer" <bohmer at gmail.com> writes:

> > No, it's not. (COERCE ... 'function) takes literal lambda expressions,
> > but ENSURE-FUNCTION should not.
>
> I have probably not understood how to use ensure-function.
> So I looked in to the functions.lisp file to check it out. But, I'm
> still not sure what would be wrong about sending ensure-function a
> literal-lambda expression. Explain please :)
> It would fit it's name better if it took a lambda list, though.

ENSURE-FUNCTION's purpose is to normalize a function designator (or
actually an /extended/ function designator) to a function object. 

A lambda expression is not a valid function designator. (And a lambda
list is something else entirely.)


> Another function I found is disjoint. And according to google: Two
> sets are disjoint if they have no element in common.
> To me, that is like XOR, while Alexandrias definition of disjoint, is
> more like OR. Am I wrong again?

It's "disjoin", not "disjoint"; look for inclusive disjunction, and
compare it to exclusive disjunction. 

Also notice that Dylan (the historical, and in some respects a
content-wise successor of Common Lisp) defines CONJOIN, and DISJOIN.

  -T.