Here's toy language for 32-bit float computations in OCaml.

For example, if you want to compute the n'th harmonic number, you could encode this as:
    let harmonic : compiled_fn = 
      compile { 
        name ="harmonic";
        inputs = ["n"];
        body = Sum("i", Num 1.0, Var "n", Div(Num 1.0, Var "i"));
      }

Your function gets compiled to native code using LLVM. You can then call 'harmonic' like this:
    run harmonic [10.0] 

Don't use this compiler in a space vehicle.  

Do use it to learn about LLVM. 

Cheers, 
Alex