Re: sortOn: sorts range of aggregates by member name(s)

[via Digitalmars-d]

On Wednesday, 5 November 2014 at 16:07:40 UTC, Nordlöw wrote:

On Wednesday, 5 November 2014 at 14:36:11 UTC, Marc Schütz wrote:

It's intuitive and concise. Plus, Ruby uses `sort` and `sort_by` for the same functionality, exactly in parallel, so it will be familiar to many users.

Here's my first working but primitive version.

https://github.com/nordlow/justd/blob/master/sort_ex.d#L15

How do I extend it to support

- variadic number of extractors
- sortBy("x")

My idea was something along these lines (untested):

    template extractorFun(alias extractor) {
        static if(is(typeof(extractor) : string)) {
            auto ref extractorFun(T)(auto ref T a) {
                mixin("with(a) { return " ~ extractor ~ "; }");
            }
        } else {
            alias extractorFun = extractor;
        }
    }

    alias fn = extractorFun!extractor;
    r.sort!((a, b) => (fn(a) < fn(b)));