On 15.03.2018 14:42, Nick Treleaven wrote:
On Wednesday, 17 January 2018 at 06:44:21 UTC, Timon Gehr wrote:
It uses tuples because it uses zip. The code does not compile today,
because the lambda I'm passing to "map" has two parameters:
auto a = [1, 2, 4, 7, 2];
auto b = [3, 5, 3, 2, 4];
// auto c = zip(a, b).map!((x, y) => x + y); // error
auto c = zip(a, b).map!(t => t[0] + t[1]); // ok
We could make lambdas consistent with proposal 5:
...
Good point. That's indeed the intention, but I didn't get around to
updating the grammar section.
...
// lambda takes one tuple of two elements
alias f = ((x, y)) => x + y;
auto c = zip(a, b).map!f; // ok
Is there a better example as to why a tuple decaying to function
arguments is worth having vs the language complication?
Yes, but I don't think a better example is even needed. If you think
((x, y)) => x + y is tolerable, you are unlikely to be convinced by a
better example.
There's also the point that it is not unreasonable to expect that it
already works when reading https://dlang.org/spec/class.html#alias-this.
