My guess is that at first it will look like existing programming languages, but with some extra commands (apply Hadamard or QFT or whatever to a register). Over

My guess is that at first it will look like existing programming languages, but with some extra commands (apply Hadamard or QFT or whatever to a register). Over time, people will find good ways to incorporate concepts like reversibility, coherent conditions, phasing, and mixing quantum/classical data deep into the language semantics. For example, Grover's algorithm could be written like this: def grover_search_sample(bit_count, predicate): qureg = qalloc(bit_count) apply X to qureg apply H to qureg n = pi/4 * 2**(bit_count/2) for _ < n: if predicate(qureg): phase_by pi if all(x_axis(qureg)): phase_by pi return measure qureg