Icon's compiler used to generate somewhat readable C output. It was still the result of continuation passing style conversion (CPS) though, so it wasn't exactly easy to follow. Nowadays Icon only has an interpreter :(
If you want something like Icon or a Lisp or Scheme to generate readable C, you're going to have to use Simon Tatham's C co-routine scheme [0] (used by PuTTY) so that you can keep code looking sequential. You'd have to generalize the co-routine thing so it's not so much about co-routines but about closures (the two concepts are remarkably related). If you allocate call frames on the stack, then you get depth-first search and backtracking support, and closures of dynamic extent. If you allocate call frames on the heap then you get breadth-first search and backtracking, closures of indefinite extent, and co-routines.
(PuTTY has all of the SSHv1 and SSHv2 protocol up to the end of authentication coded as one enormous function each, and this reads surprisingly well in spite of being such enormous functions. That works for PuTTY because those protocols are extremely sequential up to the end of authentication. Think of Simon Tatham's co-routines a an await for C.)
If you want something like Icon or a Lisp or Scheme to generate readable C, you're going to have to use Simon Tatham's C co-routine scheme [0] (used by PuTTY) so that you can keep code looking sequential. You'd have to generalize the co-routine thing so it's not so much about co-routines but about closures (the two concepts are remarkably related). If you allocate call frames on the stack, then you get depth-first search and backtracking support, and closures of dynamic extent. If you allocate call frames on the heap then you get breadth-first search and backtracking, closures of indefinite extent, and co-routines.
(PuTTY has all of the SSHv1 and SSHv2 protocol up to the end of authentication coded as one enormous function each, and this reads surprisingly well in spite of being such enormous functions. That works for PuTTY because those protocols are extremely sequential up to the end of authentication. Think of Simon Tatham's co-routines a an await for C.)
[0] https://www.chiark.greenend.org.uk/~sgtatham/coroutines.html