NAME

       Event - First-class synchronous communication.

Module

       Module   Event

Documentation

       Module Event
        : sig end

       First-class synchronous communication.

       This  module  implements synchronous inter-thread communications over channels. As in John
       Reppy's Concurrent ML system, the communication events are first-class values: they can be
       built and combined independently before being offered for communication.

       type 'a channel

       The type of communication channels carrying values of type 'a .

       val new_channel : unit -> 'a channel

       Return a new channel.

       type +'a event

       The type of communication events returning a result of type 'a .

       val send : 'a channel -> 'a -> unit event

       send  ch  v  returns the event consisting in sending the value v over the channel ch . The
       result value of this event is () .

       val receive : 'a channel -> 'a event

       receive ch returns the event consisting in receiving a value from the  channel  ch  .  The
       result value of this event is the value received.

       val always : 'a -> 'a event

       always  v  returns an event that is always ready for synchronization.  The result value of
       this event is v .

       val choose : 'a event list -> 'a event

       choose evl returns the event that is the alternative of all the events in the list evl .

       val wrap : 'a event -> ('a -> 'b) -> 'b event

       wrap ev fn returns the event that performs the same communications as ev  ,  then  applies
       the post-processing function fn on the return value.

       val wrap_abort : 'a event -> (unit -> unit) -> 'a event

       wrap_abort ev fn returns the event that performs the same communications as ev , but if it
       is not selected the function fn is called after the synchronization.

       val guard : (unit -> 'a event) -> 'a event

       guard fn returns the event that, when synchronized,  computes  fn()  and  behaves  as  the
       resulting  event.  This  enables  computing  events  with  side-effects at the time of the
       synchronization operation.

       val sync : 'a event -> 'a

       'Synchronize' on an event: offer all the  communication  possibilities  specified  in  the
       event  to the outside world, and block until one of the communications succeed. The result
       value of that communication is returned.

       val select : 'a event list -> 'a

       'Synchronize' on an alternative of events.  select evl is shorthand for sync(choose evl) .

       val poll : 'a event -> 'a option

       Non-blocking version of Event.sync : offer all the communication  possibilities  specified
       in  the  event to the outside world, and if one can take place immediately, perform it and
       return Some r where r is the result value of that communication.  Otherwise,  return  None
       without blocking.