Monads in C#

        internal Maybe<Id<ReplicaInfo>> ReplicaIdFromPath(Path path)
        {
            return (from jid in this.JobIdFromPath(path)      // Parse jobId from path.
                    from rid in this.JobReplicaMap[jid]       // Look up replicaId from jobId
                    from rpath in this.LookupReplicaPath(rid) // Look up replica path
                    where rpath == path                       // Make sure replica path matches original path
                    select rid).FirstOrNothing();
        }