About this question

Compile-Time FSM via Template Specializations

Hard · template_metaprogramming · Quant Developer interview question · template-specialization, constexpr, compile-time, fsm, non-type-template, template-metaprogramming

C++ template metaprogramming enables the creation of compile-time finite-state machines (FSMs), a technique crucial for building high-performance systems like exchange matching engines. By encoding state transition logic using template specializations, the FSM lookup table can be evaluated entirely by the compiler into a constexpr array. This approach eliminates runtime overhead and enforces valid transitions through the type system, guaranteeing performance and correctness for order lifecycle m