On Wednesday, 25 October 2017 at 08:09:52 UTC, Gary Willoughby
wrote:
On Tuesday, 24 October 2017 at 17:30:27 UTC, Andrey wrote:
Hello, why there are no named arguments for functions like,
for example, in kotlin i.e.:
int sum(in int a, in int b) {
return a + b;
}
sum(a = 1, b = 2);
This has been discussed to death:
http://forum.dlang.org/post/[email protected]
and you can do it as a library so no need to go in the language:
https://github.com/CyberShadow/ae/blob/master/utils/meta/args.d
Thanks for that link. Unaware of CyberShadow's work (which
probably is of better quality) I just had a go:
```
void foo(int one, int two, double three, string four) {
import std.stdio;
writeln("one=", one, "; two=", two, "; three=", three, ";
four=", four);
}
int first = 1;
void main()
{
// Ordinary:
foo(first, 2, 3.0, "4"); // Prints one=1; two=2; three=3;
four=4
// Named arguments:
named!(foo, "four", "4",
"two", 2,
"one", first,
"three", 3.0); // idem
}
import std.traits;
auto named(alias F, args...)() if (isFunction!F) {
import std.meta;
alias names = Stride!(2, args[0..$]);
alias values = Stride!(2, args[1..$]);
bool cmp(alias valueA, alias valueB)() {
import std.algorithm.searching;
return countUntil([ParameterIdentifierTuple!F],
names[staticIndexOf!(valueA, values)]) <
countUntil([ParameterIdentifierTuple!F],
names[staticIndexOf!(valueB, values)]);
}
return F(staticSort!(cmp, values));
}
```
Not battle tested, but it works here. There is a limitation that
the variable "first" cannot be local, but people better at this
stuff may be able to remove that.
Bastiaan.
