I've been working for a while on a sort of language for writing highly optimized cryptographic code, mostly elliptic curve cryptography where there's a very ele

I've been working for a while on a sort of language for writing highly optimized cryptographic code, mostly elliptic curve cryptography where there's a very elegant mathematical description, but when you try to optimize every single detail manually it's easy to get very dirty code. The idea was then to have a language that maintains the elegance and clarity, and a compiler that generates in my case C code. This let me focus on the "core" of a compiler, without too much emphasis on parsing, tons of optimizations, corner cases. So this would be my advice. Pick a domain, maybe focus on getting highly optimized code, design a small language and build your first compiler.