Hi Phil,

On 12 Nov 2014, at 12:54, phil@highoctane.be wrote:

Looking at LRUCache tests, I've found this:

testFibonacci "After an idea by Jan Vrany. Recursively enter the cache and its access protection"

| fibCache | fibCache := self newCache. fibCache maximumWeight: 32; beThreadSafe; factory: [ :key | key < 2 ifTrue: [ key ] ifFalse: [ (fibCache at: key - 1) + (fibCache at: key - 2) ] ]. self assert: (fibCache at: 40) equals: 102334155

the factory thing basically solves the problem.

Good ;-)

Is there more docs about the caching somewhere? I read the code, comments, and unit tests but still, will value an explanation.

I tried to comment everything, the class comments (check AbstractCache too) are quite extensive. What else do you want to know ?

Keying by object works, but with symbols, it isn't behaving. I think I miss something here.

I don't understand, AFAIK you can use any object as both key and value, most tests use Symbols. Can you elaborate ?

Is the cache size set at a given limit?

I think you are looking for CacheWeight (read the class comment). Basically, a cache has a weight, if it is exceeded, it starts removing items. How you compute the weight is up to you, the default is that each entry has a weight of 1, so you end up counting the entries. But you could use something like file or byte size of the value.

I see keyIndex is Dictionary new. What if I do have a lot of keys? Is the dictionary being copied over and over to get to the right size?

Yes, of course it is a dictionary that grows when needed, what else do you want ? You want to predefine it at a certain size ? Sven PS: BTW, the implementation is slightly more complicated than what you would expect, it uses a double linked list and an index dictionary, to achieve proper O(1) performance in its common operations (accessing, adding & evicting entries).

Phil

Phil

Phil

On Tue, Nov 11, 2014 at 7:52 PM, phil@highoctane.be <phil@highoctane.be> wrote: I should ask more questions :-).

Now, this still doesn't answer the question on how to use this to memoize object methods.

I think that what is closest to what I am looking for is this:

http://wiki.tcl.tk/10779 http://wiki.tcl.tk/10981

I am use we can do something like that in Pharo, with some memoize method in Object playing around with thisContext.

SomeClass>>someMethodWith: aSomething and: aSomethingElse

Like self haltIf: aSymbol will break if aSymbol is in the call stack.

Any guru having a way to do that?

Phil

On Tue, Nov 11, 2014 at 7:21 PM, Torsten Bergmann <astares@gmx.de> wrote: Werner Kassens wrote:

...

Hi, now this a nice idea, especially the memoizedUsing:cache idea. i would really appreciate it, if that would be MIT licenced. werner

It already is, thanks to the permission of author John Cromartie who answered us today. Both methods are in a slice already:

Details in https://pharo.fogbugz.com/f/cases/14458

Thx T.