The array to scan.
The pattern to match.
The evaluation predicate, which should return true if e1 is equal to e2 and false if not. This predicate may be any callable type.
The number of elements matching needle.
auto buffer = createBuffer("gbbbi"); test!("==")(count(buffer, 'b'), 3);
test!("==")(count("gbbbi", 'b'), 3);
Performs a linear scan of haystack from [0 .. haystack.length$(RP), returning a count of the number of elements matching needle. Comparisons will be performed using the supplied predicate or '==' if none is supplied.