2017-11-07 11:36 GMT+01:00 Thierry Goubier <thierry.goubier@gmail.com>:

2017-11-07 11:24 GMT+01:00 Denis Kudriashov <dionisiydk@gmail.com>:

2017-11-07 9:23 GMT+01:00 Nicolas Cellier <nicolas.cellier.aka.nice@gmail.com>:
I have other ideas yet.

The selector undefinedFirst is good, but the implementation not so.
I don't like the UndefinedSortFunction: too specific, compose oddly...

In the PR, collatedBy: is the way to tell how we sort properties (if you have a better name, go, it's bikesheding day)

�� "sort by size of name"
�� (people sorted: (#name collatedBy: #size))
�� =�� (people sorted: [:p| p name size])

It is nice idea but it should be not bound to sort functions. Because this feature is useful for other block based messages:
people collect: #name >> #size
people select: #name >> #size >> #even
(I use >> as example).��
Generally it is about functional programming. Would be nice to have this in image because it will simplify scripting a lot.��
I remember nice set of blog posts from Vassili Bykov about such kind of things��http://blog.3plus4.org/2007/03/.

This code has a cost, however.

First, it's rather slow (hidden #perform: in there).

Second, I had a first hand experience that it is making it significantly more complex to understand for newcomers (implying that it creates additional, special semantics compared to basic smalltalk). I know that there is no special semantic involved, but it looks as if to practitionners of other programming languages and their complex semantics.

I do like the SortFunctions idea (and its extension), but it's important IMHO to not make it too cryptic.

That's why I said it is not related to SortFunction.��

Generally we rarely use symbol for #collect:/#select: in production. But it is supper handy for scripting/debugging/inspecting. I use it all the time.

Also performance in that case can be covered by Sista.

Another problem: it complicates debugging because it is not easy to step into selector in that case. With block we just press "Through" button and we are done. But I am sure we can improve it too. Our debugger is in our hands.

Another advantage of symbol based functions: there is not potential memory leak here. In case of block we always have reference to outer context. So it is dangerous to use blocks in caches for example.

��
Regards,

Thierry