[alexandria-devel] EXTREMUM

[Nikodemus Siivola]

On 25 April 2012 15:30, Nikodemus Siivola <nikodemus at random-state.net> wrote:

>> CL-UTILITIES calls this function EXTREMUM. (It also provides a couple
>> of more functions along the lines to cover some edge cases.)
>
> Pushed a version. Can you verify that it is what you wanted, and
> performs acceptably?

So, what about the NO-EXTREMUM thing?

I think it's good that the behaviour specified, instead of depending
on the PREDICATE and REDUCE, but an an interface NO-EXTREMUM +
CONTINUE is terrible: unless you handle the error right around the
call site, it's pointless, since no-one higher up the call stack can
know for sure where the error came from. At the call site it is overly
verbose and inefficient:

 (handler-bind ((no-extremum #'continue))
    (extremum ...))

I would much like to remove mention of the restart from the docstring,
and add &KEY DEFAULT instead:

    (extremum ... :default nil)

would provide the same behaviour as invoking CONTINUE. Since you
obviously actually use this thing, any comments?

Cheers,

 -- Nikodemus