From: "Eregon (Benoit Daloze)" Date: 2022-01-14T12:58:22+00:00 Subject: [ruby-core:107127] [Ruby master Feature#18368] Range#step semantics for non-Numeric ranges Issue #18368 has been updated by Eregon (Benoit Daloze). One way to achieve the same result currently is Enumerator.produce: ```ruby require 'time' Enumerator.produce(Time.parse('2021-12-01')) { _1 + 24*60*60 }.take_while { _1 <= Time.parse('2021-12-24') } ``` Somewhat related to https://bugs.ruby-lang.org/issues/18136#note-15 (where `<=` can't be used). But I think `step` should just use `+` and `<` (for `exclude_end?`)/`<=`, I don't see any reason to prevent the above cases, `([]..).step([1]).take(3)` can actually be useful. ---------------------------------------- Feature #18368: Range#step semantics for non-Numeric ranges https://bugs.ruby-lang.org/issues/18368#change-95974 * Author: zverok (Victor Shepelev) * Status: Open * Priority: Normal ---------------------------------------- I am sorry if the question had already been discussed, can't find the relevant topic. "Intuitively", this looks (for me) like a meaningful statement: ```ruby (Time.parse('2021-12-01')..Time.parse('2021-12-24')).step(1.day).to_a # ^^^^^ or just 24*60*60 ``` Unfortunately, it doesn't work with "TypeError (can't iterate from Time)". Initially it looked like a bug for me, but after digging a bit into code/docs, I understood that `Range#step` has an odd semantics of "advance the begin N times with `#succ`, and yield the result", with N being always integer: ```ruby ('a'..'z').step(3).first(5) # => ["a", "d", "g", "j", "m"] ``` The fact that semantic is "odd" is confirmed by the fact that for Float it is redefined to do what I "intuitively" expected: ```ruby (1.0..7.0).step(0.3).first(5) # => [1.0, 1.3, 1.6, 1.9, 2.2] ``` (Like with [`Range#===` some time ago](https://bugs.ruby-lang.org/issues/14575), I believe that to be a strong proof of the wrong generic semantics, if for numbers the semantics needed to be redefined completely.) Another thing to note is that "skip N elements" seem to be rather "generically Enumerable-related" yet it isn't defined on `Enumerable` (because nobody needs this semantics, typically!) Hence, two questions: * Can we redefine generic `Range#step` to new semantics (of using `begin + step` iteratively)? It is hard to imagine the amount of actual usage of the old behavior (with String?.. to what end?) in the wild * If the answer is "no", can we define a new method with new semantics, like, IDK, `Range#over(span)`? -- https://bugs.ruby-lang.org/ Unsubscribe: