Library of efficient algorithms and data structures ported to templatized D from attractivechaos' generic C approach: https://github.com/attractivechaos/klib

Comparison with emsi containers HashMap:

Time, in msec, for n=500,000 operations benchmarked on linux VM; ldc2 -release

Key type may be numeric, C style string, D style string. If numeric, must be unsigned.

May be used as a hash map (default) or a hash set. To use as a hash set, pass optional third template parameter kh_is_map = false.

By default, memory allocated by the hashmap will be scanned by the GC. (pass optional fourth template parameter useGC = false to disable)

Can undergo static initialization (e.g. define as struct member with no extra init code needed in struct ctor), unlike emsi containers HashMap.

auto map = khash!(keytype, valuetype);

map["monty"] = "python";

auto val = map[key];

auto val = map.require("fruit", "apple");

foreach(x; map.byKey) {
...
}

auto kh = khash!(uint, char)();
kh[5] = 'J';
assert(kh[5] == 'J');

kh[1] = 'O';
kh[99] = 'N';

// test: foreach by key
import std.array : array;
assert(kh.byKey().array == [5, 1, 99]);

auto kh_string = khash!(string, int)();
kh_string["test"] = 5;
assert( kh_string["test"] == 5 );

auto kh_valstring = khash!(uint, string)();
kh_valstring[42] = "Adams";
assert( kh_valstring[42] == "Adams" );

const auto fw = kh_string.require("flammenwerfer", 21);
assert(fw == 21);

Please let me know what you find. There may be a double free bug when making a hashmap of hashmaps.