I was trying to implement an interpreter for a minimal (lazy) language in C [1]. It uses Church encoding and other encodings. E.g. here are the definitions of false, true, identity, and pair:

    f_ = proc_self(lambda(v0));
    t_ = proc(lambda(v1), f());
    id_ = proc(v0, f());
    pair_ = lambda3(op_if(v0, v1, v2));

For the moment I gave up on it though but maybe it might serve as inspiration ;)

[1] https://github.com/wedesoft/blc/blob/master/src/x.c#651