[Issue 13936] groupBy must be redone

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=13936

--- Comment #37 from hsteoh at quickfur.ath.cx ---
As far as groupByAdjacent is concerned, I am still of the opinion that it
belongs as part of groupBy. But since you apparently regard groupBy as
release-critical, perhaps it may be wiser to defer this issue to later -- we
can always extend groupBy later to encompass the additional functionality, even
if it involves unhappy users filing bugs about why groupBy can't handle certain
kinds of predicates. Whereas if we release with support for both now, it will
be hard to retract one later (at the very least it will involve the dreaded
deprecation cycle and consequent unhappy users filing regressions about their
predicates breaking). So perhaps for this release we should only include
groupBy with support only for equivalence relations, and then we'll have more
time to fight it out over whether groupBy should be extended or groupByAdjacent
should be introduced. :-P

But, that aside, since you have already written most of the code, I may just
copy-n-paste it and fix some of the most egregious flaws in it before
submitting it. :-P  No predicting how the reviewers will react, though.

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