On Mon, Dec 09, 2002 at 08:36:20PM -0000, Smylers wrote:
> I was wondering whether it'd be better to have this specified per
> C<return> rather than per C<sub>. That'd permit something a long the
> lines of:
>
> sub days_in_month(Str $month, Int $year)
> {
> ....
> }
>
> Perhaps there are only some edge cases which require calculation; or the
> function is liable to be called with many invalid input values, which
> can quickly be determined yield C<undef> and so which don't need
> caching; or there is a pattern as to which sets of input parameters are
> likely to be passed multiple times so the function only bother caching
> those.
It doesn't matter whether some of the values are cheap lookups
while other values are "complex calculations". Once a cached sub
is called with a set of parameter values, the return value will
always be a cheap lookup in the memoized sub's cache.
It's irrelevant if you have a different but comparable "cheap
lookup" for some values.
> Anybody else like this, or are we better off leaving things as they
> were?
I think you're trying to overoptimize something here. I can't see
a benefit to caching only sometimes. If there is, then you probably
want to implement a more sophisticated cache management strategy
for your sub, not warp the language for a special case.
Z.
