Added List.sort(comp) to List module

[mathewmariani]

Added sort(comp) function to List using an in-place quicksort implementation.

[CohenArthur]

Your doc example shows it, but it would be nice to have some documentation on the expected behavior of comp(). For example, saying it must take two arguments and return a bool, etc etc

[mathewmariani]

Your doc example shows it, but it would be nice to have some documentation on the expected behavior of comp(). For example, saying it must take two arguments and return a bool, etc etc

Thanks for pointing that out. I just updated the docs and added a default comp functions

[mhermier]

From my experience at using the language, I would recommend to change sort() to be a uni-line. Stub functions are only meant to provide default values or simply computed values, they should behave exactly like their parent and also return the same thing. While technically equivalent in your case, making it already there, express intent more, avoid possible future bugs and late fixing.

So as a rule of thumb; if you write a one liner, it is highly likely you want to return the computed value, so use the real one liner expression (that implicitly returns the computed value). I know, it is not really intuitive or does not scale producing changes, but the language is like this...

[mathewmariani]

From my experience at using the language, I would recommend to change sort() to be a uni-line. Stub functions are only meant to provide default values or simply computed values, they should behave exactly like their parent and also return the same thing. While technically equivalent in your case, making it already there, express intent more, avoid possible future bugs and late fixing.

So as a rule of thumb; if you write a one liner, it is highly likely you want to return the computed value, so use the real one liner expression (that implicitly returns the computed value). I know, it is not really intuitive or does not scale producing changes, but the language is like this...

Just to clarify you mean a uni-line (stub function) like so sort() { sort {|a, b| a < b} } or is there a Wren style that im missing?

[mhermier]

Yes this one, it act as a stub with implicit returning.

[bjorn]

Some comments based on code review, I didn't test it.

[mhermier]

Does the tests pass now ?

[mathewmariani]

Does the tests pass now ?

Not with the stack corruption issue

[mhermier]

I think the test should be a bit more atomic to be more interesting.

[mathewmariani]

I rebased from main and can confirm the tests are passing

[bjorn]

@mathewmariani It seems you did a rebase followed by a merge. Please get rid of the merge for force-push just the rebased version of your branch.

[mathewmariani]

@mathewmariani It seems you did a rebase followed by a merge. Please get rid of the merge for force-push just the rebased version of your branch.

I believe that's it

[mathewmariani]

Should I resolve all the comments, or leave that up to the commenters?

[bjorn]

@mathewmariani I see most of my comments marked as "Outdated" and I see no way to resolve them (neither the ones that haven't been marked outdated), so I guess that's on you.

[mathewmariani]

Anything else needed for this to be merged?

[ChayimFriedman2]

Nice work. Three things, however:

1. I think it's preferred to implement this in C. Wren prefers to implement the core in C (speed).
2. You implemented a quick sort. Do we need a stable sort instead?
3. Should we add a non in-place sort, too? (Maybe a method in Sequence). It can be just:

   class Sequence {
     // ...
     sort() { sort {|a, b| a < b } }
     sort(comparer) { toList.sort(comparer) }
   }

[avivbeeri]

I don't think it's semantically appropriate to have a Sequence.sort method, because a sequence could in theory be infinite in length (and they can be lazily evaluated), so a sorting operation would be impossible or intractable.

[ruby0x1]

Also a sort function in c runs into reentrancy (specifically, it's not possible when a user supplied compare function is involved)

[ChayimFriedman2]

@ruby0x1 I think the reentrancy is about to be solved, am I wrong?

@avivbeeri I know that, be that still holds in Python for example, and it does have a sorted() function that operates on iterables.

[mathewmariani]

@ChayimFriedman2 I implemented Quick Sort since it's the algorithm used in Lua's table.sort
@ruby0x1 is there anything left that I should be adding for this MR?

[ruby0x1]

I'll look closely soon, busy with some other Wren stuff locally.

[mhermier]

To help comprehension, could you replace 'a' and 'b' with something like 'i' and 'j' where iterators are expected.

[ChayimFriedman2]

I think start and end would be better.

[mathewmariani]

@ChayimFriedman2 @mhermier I'm leaning towards i and j since that's what you find in most books. I also like more compact code.

[ruby0x1]

@mathewmariani code is for humans, not machines, legibility > compactness. Especially for wren, which strives to help people learn and understand, making the code clearer is part of that goal. In my code I used low high but start and end is also clear enough. I would prefer not to use single letter variables here.

[ruby0x1]

Thanks @mathewmariani , I'll probably tweak some things after merging, but looks good from here.