On Sunday, 21 June 2020 at 00:06:12 UTC, Paul Backus wrote:
Are you tired of D's sane, straightforward scoping rules?
Itching for a taste of that old-fashioned C++ madness? Well,
itch no more: addle is here to help.
addle is a tiny library that implements C++-style
argument-dependent lookup (ADL) for D, on an opt-in basis. It
lets you extend existing types with UFCS methods, and share
those methods seamlessly with code in other modules--no
`import` required!
Here's a brief example:
import addle;
import std.range;
// Import a type from another module
import mylib: MyStruct;
// Define range primitives for MyStruct
bool empty(MyStruct a) { return false; }
string front(MyStruct a) { return "ok"; }
void popFront(MyStruct a) {}
// MyStruct isn't considered an input range, because
// std.range can't see our UFCS methods.
static assert(isInputRange!MyStruct == false);
// ...but extending it makes those methods visible.
static assert(isInputRange!(Extended!MyStruct));
void main()
{
import std.range: take, only;
import std.algorithm: equal;
MyStruct myStruct;
// Now we can use all of the standard range algorithms
assert(
myStruct.extended
.take(3)
.equal(only("ok", "ok", "ok"))
);
}
Now available on Dub, by "popular demand"!
Links:
- Documentation: https://addle.dpldocs.info/addle.html
- Dub: https://code.dlang.org/packages/addle
- Github: https://github.com/pbackus/addle
That's pretty neat.
I wonder if something like that could have been used when
checking types in phobos? Probably wouldn't be implemented as I
can imagine a performance impact during compilation tho.
