import std.stdio;

import std.array;

import std.traits;

​

string interp(string code, alias P1)() {

    string s = code;

    s = s.replace("$"~__traits(identifier, P1), P1);

    return s;

}

​

void main() {

    enum txt = "auto test";

    pragma(msg, interp!(`$txt = 3;`, txt));

    mixin(interp!(`$txt = 3;`, txt));

}