Compile Time Fun Time

[Yevano]

I am writing a domain specific language of sorts in D for the 
lambda calculus. One of my requirements is that I should be able 
to generate expressions like this:

new Abstraction(v1, M)

like this:

L!(x => M)

It is common to want to write things like

L!(x => L!(y => M))

but it is much nicer to write that like

L!((x, y) => M)

So, I have created a templated function for this.

Abstraction L(alias f)() {
     static if(__traits(compiles, f(null))) {
         auto v1 = new Variable;
         return new Abstraction(v1, f(v1));
     } else static if(__traits(compiles, f(null, null))) {
         auto v1 = new Variable;
         auto v2 = new Variable;
         return new Abstraction(v1, new Abstraction(v2, f(v1, 
v2)));
     } else static if(__traits(compiles, f(null, null, null))) {
         auto v1 = new Variable;
         auto v2 = new Variable;
         auto v3 = new Variable;
         return new Abstraction(v1, new Abstraction(v2, new 
Abstraction(v3, f(v1, v2, v3))));
     }
}

This only works for at most 3 parameter delegates. If I want to 
add more, I have to linearly add more static ifs in the obvious 
way. However, I believe I can make this function scalable using 
string mixins and other magic. Any insight into this is much 
appreciated.