Serialize D types to json

json.d

module json;

import std.conv;
import std.array;
import std.traits;

string json(T) (T obj) {
    static if (is(typeof(obj) == string)) {
        return "\"" ~ obj.replace("\\", "\\\\").replace("\"", "\\\"") ~ "\"";
    } else static if (isBasicType!(typeof(obj))) {
        return to!string(obj);
    } else static if (isArray!(typeof(obj))) {
        string res = "";

        foreach (val; obj) {
            res ~= json(val) ~ ",";
        }

        if (res.length > 0) res = res[0..$-1];

        return "[" ~ res ~ "]";
    } else {
        string res = "";

        foreach (mem; __traits(allMembers, typeof(obj))) {
            static if (!isCallable!(__traits(getMember, obj, mem)) && __traits(compiles, json(__traits(getMember, obj, mem)))) {
                auto val = __traits(getMember, obj, mem);
                res ~= "\"" ~ mem ~ "\":" ~ json(val) ~ ",";
            }
        }

        if (res.length > 0) res = res[0..$-1];

        return "{" ~ res ~ "}";
    }
}