import std.c.stdio;
import std.string;

template toData(T) {
	void[] toData(T t) {
		union u {
			T value;
			void[] data;
		}
		u uu;
		uu.value = t;
		return uu.data;
	}
}

template fromData(T) {
	T fromData(void[] d) {
		union u {
			T value;
			void[] data;
		}
		u uu;
		uu.data = d;
		return uu.value;
	}
}

void print(char[] format, void[][] data) {
	int idx;
	char c;
	char[] text;

	for (int i; i < format.length; i++) {
		c = format[i];
		if (c != '%') {
			text ~= c;
			continue;
		}
		c = format[++i];
		switch (c) {
			case '%':
				text ~= '%';
				break;

			case '#':
				text ~= toString(data.length);
				break;

			case 'd':
				text ~= toString(fromData!(int)(data[idx++]));
				break;

			case 's':
				text ~= fromData!(char[])(data[idx++]);
				break;
		}
	}

	foreach (char c; text) {
		putchar(c);
	}
}

void main() {
	void[][] data;
	data ~= toData!(int)(123);
	data ~= toData!(char[])(\" "hello" \");
	print("
This should be 123: %d
This should be \"hello\": %s
This should be three percent signs: %%%%%%
This should be 2: %#
", data);
}