Exercise 5.49: As an alternative to using the
explicit-control evaluator’s read-eval-print loop, design a register machine
that performs a read-compile-execute-print loop.  That is, the machine should
run a loop that reads an expression, compiles it, assembles and executes the
resulting code, and prints the result.  This is easy to run in our simulated
setup, since we can arrange to call the procedures compile and
assemble as “register-machine operations.”