Concurrency – implement parallel execution in scheme

In SiCp Section 3.4 (serializer in scheme) on currency, there is a process called parallel execution, which is described in MIT scheme but not implemented I wonder if anyone has actually implemented it; If not, how to start implementing such a procedure?

http://mitpress.mit.edu/sicp/full-text/book/book-Z-H-23.html#%_sec_3.4.1

Solution

This is how I use racket to implement parallel execution to solve the exercise in Section 3.4 of SiCp:

(define (parallel-execute . procs)
  (map thread-wait
       (map (lambda (proc) (thread proc))
            procs)))

I can't guarantee that it has the same semantics as the parallel execution process defined in this book, but it allows me to solve the practice