[dmd-concurrency] draft 4

[Sean Kelly]

On Jan 12, 2010, at 12:51 PM, Robert Jacques wrote:
> 
> I know this is a bit of a bike shed, but I'd prefer something shorter for receiveOnly, (like recv or receive) as A) type-checked message passing should be the easy/default way to do things and B) it's easy to define recv!()() to return the unchecked message using a variant. I'd also like to be able to use recv(tid,i); in addition to recv!(Tid, int)(); but I haven't been able to get the templates to not clash with each other.

In my sample message passing implementation I use these prototypes:

    void sendmsg(T...)( Pid pid, T vals );
    void recvmsg(T...)( T ops );

Sample call:

    sendmsg( pid, 2, "hi" );
    ...
    recvmsg( (MyStruct s) {},
                     (int a, string b) { writefln( "got %s, %s", a, b ); } );

I guess an explicit receive prototype would be:

    auto val = recvtype!T();

That could be translated to:

    T recvtype(T)()
    {
        T ret;
        recvmsg( (T val) { ret = val; },
                          (Variant val) { throw new Exception( "unexpected value" ); } );
        return ret;
    }

Not sure if it would be possible to use the same function name for both, though because the effect is so different you may really want different names anyway.