Hi Richard and Sebastian!
Interesting read. I obviously was not aware of the variety of meanings for fold/reduce. Thanks for pointing this out. Also, in some languages it seems the same name is used for both reductions with and without an initial value. There's even a list on WP on the matter: https://en.wikipedia.org/wiki/Fold_%28higher-order_function%29#In_various_languages Kind regards, Steffen Richard O'Keefe schrieb am Donnerstag, 13. April 2023 13:16:28 (+02:00): The standard prelude in Haskell does not define anything called "fold". It defines fold{l,r}{,1} which can be applied to any Foldable data (see Data.Foldable). For technical reasons having to do with Haskell's non-strict evaluation, foldl' and foldr' also exist. But NOT "fold". https://hackage.haskell.org/package/base-4.18.0.0/docs/Data-Foldable.html#laws On Thu, 13 Apr 2023 at 21:17, Sebastian Jordan Montano <sebastian.jor...@inria.fr> wrote: Hello Steffen, Let's take Kotlin documentation (https://kotlinlang.org/docs/collection-aggregate.html#fold-and-reduce) > The difference between the two functions is that fold() takes an initial > value and uses it as the accumulated value on the first step, whereas the > first step of reduce() uses the first and the second elements as operation > arguments on the first step. Naming is not so consistent in all the programming languages, they mix up the names "reduce" and "fold". For example in Haskell "fold" does not take an initial value, so it is like a "reduce" in Kotlin. In Kotlin, Java, Scala and other oo languages "reduce" does not take an initial value while "fold" does. Pharo align with those languages (except that out fold is called #inject:into:) So for me the Pharo methods #reduce: and #inject:into represent well what they are doing and they are well named. Cheers, Sebastian ----- Mail original ----- > De: "Steffen Märcker" <merk...@web.de> > À: "Any question about pharo is welcome" <pharo-users@lists.pharo.org> > Envoyé: Mercredi 12 Avril 2023 19:03:01 > Objet: [Pharo-users] Collection>>reduce naming > Hi! > > I wonder whether there was a specific reason to name this method #reduce:? > I would have expected #fold: as this is the more common term for what it > does. And in fact, even the comment reads "Fold the result of the receiver > into aBlock." Whereas #reduce: is the common term for what we call with > #inject:into: . > > I am asking not to annoy anyone but out of curiosity. It figured this out > only by some weird behaviour after porting some code that (re)defines > #reduce . > > Ciao! > Steffen -- Gesendet mit Vivaldi Mail. Laden Sie Vivaldi kostenlos von vivaldi.com herunter.
