It's not contradictory. A Haskell function(modulo io and boundless recursion) gets compiled to combinational logic without registers. a digital circuit circuit

It's not contradictory. A Haskell function(modulo io and boundless recursion) gets compiled to combinational logic without registers. a digital circuit circuit in clash are normal Haskell function combined together with registers and other combinators. Clash can compile to an executable as well as to hardware. The executable is a cycle accurate simulation of the circuit.