Re: parallel with no exprs

[Kevin Ryde]

Mikael Djurfeldt <address@hidden> writes:
>
>       (use-modules (ice-9 threads))
>       (call-with-values
>           (lambda ()
>               (display "hello\n")
>             (parallel))
>         (lambda ()
>           (display "hi\n")))

I get

        hello
        ERROR: Wrong number of arguments to #<procedure #f ()>

I'd seen (parallel) expanding to (begin), which was what made me think
it was the (begin) that might not be right, since the following gives
the same error.

        (call-with-values
            (lambda ()
              (display "hi\n")
              (begin))
          (lambda ()
            (display "bye\n")))

> (lambda () (parallel)) correctly yields an error
> message since that is a lambda with no expressions in the body.

Ah, somehow I missed that (lambda () (begin)) is itself an empty body.
Bit subtle that, since of course it doesn't look empty :-).