A module that re-exports all the parts of the library related to tracing.
The idea of tracing is to record the concurrent events (i.e. channel communications and barrier synchronisations) that occur during a run of the program. You can think of it as automatically turning on a lot of debug logging.
Typically, at the top-level of your program you should have:
main :: IO () main = runCHP myMainProcess
To turn on the tracing mechanism of your choice (for example, CSP-style tracing) to automatically print out the trace after completion of your program, just use the appropriate helper function:
main :: IO () main = runCHP_CSPTraceAndPrint myMainProcess
It could hardly be easier. If you want more fine-grained control and examination
of the trace, you can use the helper functions of the form
that give back a data structure representing the trace, which you can then
manipulate. The Doc used by the traces is from the
module that currently comes with GHC (I think).
- module Control.Concurrent.CHP.Traces.CSP
- module Control.Concurrent.CHP.Traces.Structural
- module Control.Concurrent.CHP.Traces.TraceOff
- module Control.Concurrent.CHP.Traces.VCR
- data RecordedEvent
- data RecordedIndivEvent
- class Show t => Trace t where
A globally recorded event, found in CSP and VCR traces. Either a channel communication (with a unique identifier of the channel) or a barrier synchronisation (with a unique identifier of the barrier). The identifiers are per channel/barrier, not per event. Currently, channels and barriers can never have the same Unique as each other, but do not rely on this behaviour.
An individual record of an event, found in nested traces. Either a channel write or read, or a barrier synchronisation, each with a unique identifier for the barrier/channel. The event will be recorded by everyone involved, and a ChannelWrite will have the same channel identifier as the corresponding channel-read. The identifiers are per channel/barrier, not per event. Currently, channels and barriers can never have the same Unique as each other, but do not rely on this behaviour.
A class representing a type of trace. The main useful function is
but because its type is only determined by its return type, you may wish
to use the already-typed functions offered in each trace module -- see the
modules in Control.Concurrent.CHP.Traces.
Runs the given CHP program, and returns its return value and the trace. The return value is a Maybe type because the process may have exited due to uncaught poison. In that case Nothing is return as the result.
The empty trace.
Pretty-prints the given trace using the Text.PrettyPrint.HughesPJ module.