On Thursday, 12 May 2016 at 10:02:46 UTC, thedeemon wrote:
On Thursday, 12 May 2016 at 09:44:39 UTC, xtreak wrote:
I came across the issue where using .array after .joiner
caused the changes to the output. The program is at
https://dpaste.dzfl.pl/0885ba2eddb4 . I tried to debug through
the output but I couldn't get the exact issue. It will be
helpful if someone confirms this as a bug.
It's not a bug per se, just probably documentation being not
clear enough. Essentially it's the same issue as with
File.byLine: a range that mutates its state, so it's ok to
consume lazily but if you just store references (as array()
does) you get references to the same mutated value as result.
Quick fix:
r.chunks(2).map!permutations.joiner.map!array.array.writeln;
i.e. copy each permutation to separate array before it's gone.
Thanks a lot. Can you kindly elaborate a little more on
File.byLine with an example of the scenario so that I don't get
bitten by it. File.byLine.array works as expected for me. A
little more explanation on the permutations will also be helpful
since joiner.map!array converts the subranges to arrays, so does
joiner work by mutating state if so how does it do.
