Re: Passing $ as a function argument

[Michael Coulombe via Digitalmars-d]

On Sunday, 14 October 2018 at 14:35:36 UTC, lngns wrote:

On Sunday, 14 October 2018 at 13:18:37 UTC, lngns wrote:

That would require introducing a new type

Or just use int with a negative number... That's how it's done in some dynamic languages. But my point is that it should be compatible with pre-existing code using unsigned indices somehow. I don't think that is possible.

Another way to do this with UFCS:

// write-once library wrapper
struct Indexer(R) {
    R r;
    auto opDollar() { return r.length; }
    auto opIndex(size_t i) { return r[i]; }
}
auto indexer(R)(R r) { return Indexer(r); }

// rewrite index parameter => return wrapped range
auto foo()
{
    auto arr = (...);
    return indexer(arr);
}

// easy-to-use result
auto end = foo[$-1];