[m-users.] Confused my det/multi error message, full disjunction of type in place.

[Julien Fischer]

On Sun, 4 Dec 2022, Sean Charles (emacstheviking) wrote:

> 
>
>       On 4 Dec 2022, at 10:50, Julien Fischer <jfischer at opturion.com> wrote:
> 
> On Sun, 4 Dec 2022, Sean Charles (emacstheviking) wrote:
>
>       And the code, I just don't understand, as usual, what the compiler is
>       trying to tell me. The io.nl/2 is det, so that can't fail, and
>       presumably the field update can't fail either. And why hasn't this
>       error been raised on all the other cases?
>            59 :- pred write_(fstate::in, fstate::out, fi::in, io::di, io::uo) is det.
>            60
>            61 write_(!S, nl, !IO) :-
>            62     io.nl(!IO),
>            63     !:S = !.S ^nl_written := yes.
>            64
>            65 write_(!S, brace_o, !IO) :-
>            66     write_(!S, s("{"), !IO),
>            67     !:S = !.S ^tab_size := !.S ^tab_size+1.
> 
>                                                    ^^^
>            68     write_(!S, nl, !IO).
> 
> 
> Presuambly, the period marked above is actually supposed to be a comma.
> (Because it's a period, you have two clauses that match nl.)
> 
> Why would it be a comma? I just don't understand, "!,S" ??? That's a syntax error surely?

I meant the period at the end of the line -- my mail client mangled that
a bit.

(e.g. it should be:

      !:S = !.S ^tab_size := !.S ^tab_size+1,
      write_(!S, nl, !IO).

)

Julien.