Rationale:
Swift's For-In-loop is fine, as long as you don't need an iteration step size other than 1/-1, in which case it becomes unexpectedly inconsistent and unwieldy.
for i in 1...10
for i in reverse(10...1)
for i in stride(from:1, through:10, by:3)
or even
for i in 1.stride(through:10, by:3)
for i in reverse(10...1)
for i in stride(from:1, through:10, by:3)
or even
for i in 1.stride(through:10, by:3)
The above sequence is not only confusing for teaching purposes/beginners (first lesson: protocols. really?), but also unnecessarily bulky for everyday use. It's a For-loop, one of the most basic and frequently used structures in any language -- please let's make it pithy.
Comparison:
Currently, even the C-style For-loop we are just about to get rid of could be argued to be more concise and consistent, but significantly more so are the likes of
# Python
for i in range(1, 10, 3):
for i in range(1, 10, 3):
-- Lua
for i = 1, 10, 3
for i = 1, 10, 3
' Basic
for i = 1 to 10 step 3
for i = 1 to 10 step 3
(* Modula-2 *)
for i := 1 to 10 by 3
for i := 1 to 10 by 3
// Chapel
for i in 1..10 by 3
for i in 1..10 by 3
or any other remotely relevant non-C-style language that allows For-loops with an altered step size.
While there are other issues like having to use reverse(1...10) instead of simply 10...1, (which compiles, but doesn't run, even when using literals -- why?) none of it goes against the grain as much as being forced to type out stride(boiboiboilerplate) for a simple iteration.
Suggestion(s):
A) Add keyword "by" as syntactic sugar, used as in Modula/Chapel (and tip our hat to Algol 68):
// Swift
for i in 1...10 by 3
for i in reverse(1...10) by -3
for i in 1...10 by 3
for i in reverse(1...10) by -3
or even better yet (if feasible):
B)
for i in 1...10 by 3
for i in 10...1 by -3
for i in 10...1 by -3
Please comment, and thanks everyone for reading.
-- Hans
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