mem_fun

オッケーメムファンですね！

http://d.hatena.ne.jp/rinset/20060530/1148987859

import std.stdio;

template mem_fun(T) {
    T (*mem_fun(T (*f)()))(Object o) {
        return cast(T (*)(Object o))f;
    }
}

class C {
    int val_;
    this(int val) { val_ = val; }
    int func() {
        return val_;
    }
}

int main() {
    auto mf = mem_fun(&C.func);
    C c1 = new C(1);
    C c2 = new C(2);
    writefln(mf(c1));
    writefln(mf(c2));
    return 0;
}

1引数メソッドを2引数にするのは……

import std.stdio;

class mem_fun_t(T, U) {
    T (*fp)(U, Object);
    this(T (*f)(U, Object)) {
        fp = f;
    }
    T opCall(Object o, U u) {
        return fp(u, o);
    }
}

template mem_fun(T, U) {
    mem_fun_t!(T, U) mem_fun(T (*f)(U)) {
        return new mem_fun_t!(T, U)(cast(T (*)(U, Object))f);
    }
}

class C {
    int val_;
    this(int val) { val_ = val; }
    int func(int x) {
        return val_+x;
    }
}

int main() {
    auto mf = mem_fun(&C.func);
    C c1 = new C(1);
    C c2 = new C(2);
    writefln(mf(c1, 3));
    writefln(mf(c2, 4));
    return 0;
}

あ、以下参考に。

http://d.hatena.ne.jp/shinichiro_h/20060215#1139942807