I just ended up using a pipe and having my other thread read from that in addition to other inputs, as custom output ports are too much of a pain to actually use.
I lost ordering of events, (i.e. cannot tell whether output to the pipe came before or after a message on another channel), but was able to mostly hack around that. On Tue, Dec 3, 2013 at 5:44 AM, Robby Findler <ro...@eecs.northwestern.edu> wrote: > Oh, right: so you probably don't want 'get' 'put' and 'is-full?' but you > want 'get' and 'try-put' that fails only when the channel is full, returning > a boolean to indicate success. > > Robby > > > On Mon, Dec 2, 2013 at 11:24 PM, David T. Pierson <d...@mindstory.com> wrote: >> >> On Fri, Nov 29, 2013 at 12:23:42PM -0800, Eric Dobson wrote: >> > I'm trying to make a custom output port that is backed by a >> > async-channel. One of the operations that ports need to provide is an >> > event that is ready when progress on the event can be made. But since >> > I cannot tell if the async-channel is full and put would not block >> > without actually sending a value, I cannot provide such an event. Is >> > it possible to provide such an API or does the implementation of >> > async-channels prevent this? >> >> I don't know much about creating custom ports, so I looked up progress >> events in order to understand your question better. But now I'm >> confused, because progress events seem to be specific to input ports, >> whereas it sounds like you are creating an output port. What am I >> missing? >> >> Regarding your actual question: I think the reason a non-side-effecting >> async-channel-put-evt is not provided is that using such an event could >> lead to race conditions. A previous thread [1] on this list touched on >> this with regard to places and channels as events; I'm extrapolating to >> extend that answer to async-channel-put-evt. >> >> David >> >> [1] http://www.mail-archive.com/users@racket-lang.org/msg15630.html >> ____________________ >> Racket Users list: >> http://lists.racket-lang.org/users > > ____________________ Racket Users list: http://lists.racket-lang.org/users
