add setutils.[]=

[timotheecour]

now that we have a dedicated std/setutils, it makes sense to add this syntax sugar, which is useful in particular when the value (true or false) isn't hard-coded, thus avoiding if ... incl else ... excl

future work

• see More sugary setutils.[]= timotheecour/Nim#643, add func []=*[T](s: var set[T], arg: set[T], val: bool) {.inline.} = => Added setutils.[]= variant #17302

[ringabout]

It is not very intuitive, do other language have similar features?

[metagn]

It is not very intuitive, do other language have similar features?

http://www.cplusplus.com/reference/bitset/bitset/operator[]/

[timotheecour]

in D:

https://dlang.org/library/std/bitmanip/bit_array.html

import std.bitmanip;
void main(string[]args){
  auto b = BitArray([1, 0]);
  assert(b[0] == true);
  b[0] = false;
  assert(b[0] == false);
}

in C++

#include <bitset>
#include <cassert>
int main (int argc, char *argv[]) {
  std::bitset<128> a;
  a[3] = true;
  assert(a[3] == true);
  return 0;
}

in swift:

https://victorqi.gitbooks.io/swift-algorithm/content/bit_set.html

var bits = BitSet(size: 140)
bits[2] = true

[beef331]

I do like the feature but really dislike the syntax, I'm suggesting s.set(a3, true), though it doesn't match the other languages but is a whole hell of a lot more readable to me.

[timotheecour]

I do like the feature but really dislike the syntax, I'm suggesting s.set(a3, true), though it doesn't match the other languages but is a whole hell of a lot more readable to me.

well []= would fit well with Tables, etc, but I'm open to a different name. set is bad though since it's even more confusing, because set itself is the type name. However put is the other obvious choice, and also is mentioned for that in nep1 (https://nim-lang.github.io/Nim/nep1.html)

vote as reaction to this comment:

• +1 to keep []=
• -1 for put

otherwise, add a comment for a different suggestion.
(note that future work may add an overload taking a set as 2nd param, eg; s.put({a0, a1}, false) vs s[{a0, a1}] = false depending on the choice made here)