Introduce trait constraints; simplify elsewhere (#445)

dogsdogsdogs/src/operators/count.rs

@@ -19,9 +19,8 @@ pub fn count<G, Tr, R, F, P>(
     index: usize,
 ) -> Collection<G, (P, usize, usize), R>
 where
-    G: Scope,
-    G::Timestamp: Lattice,
-    Tr: TraceReader<ValOwned=(), Time=G::Timestamp, Diff=isize>+Clone+'static,
+    G: Scope<Timestamp=Tr::Time>,
+    Tr: TraceReader<ValOwned=(), Diff=isize>+Clone+'static,
     Tr::KeyOwned: Hashable + Default,
     R: Monoid+Multiply<Output = R>+ExchangeData,
     F: Fn(&P)->Tr::KeyOwned+Clone+'static,

dogsdogsdogs/src/operators/half_join.rs

@@ -76,13 +76,11 @@ pub fn half_join<G, V, R, Tr, FF, CF, DOut, S>(
     mut output_func: S,
 ) -> Collection<G, (DOut, G::Timestamp), <R as Mul<Tr::Diff>>::Output>
 where
-    G: Scope,
-    G::Timestamp: Lattice,
-    Tr::KeyOwned: Ord + Hashable + ExchangeData,
+    G: Scope<Timestamp = Tr::Time>,
+    Tr::KeyOwned: Hashable + ExchangeData,
     V: ExchangeData,
     R: ExchangeData + Monoid,
-    Tr: TraceReader<Time=G::Timestamp>+Clone+'static,
-    Tr::Diff: Semigroup,
+    Tr: TraceReader+Clone+'static,
     R: Mul<Tr::Diff>,
     <R as Mul<Tr::Diff>>::Output: Semigroup,
     FF: Fn(&G::Timestamp) -> G::Timestamp + 'static,
@@ -131,13 +129,11 @@ pub fn half_join_internal_unsafe<G, V, R, Tr, FF, CF, DOut, ROut, Y, I, S>(
     mut output_func: S,
 ) -> Collection<G, DOut, ROut>
 where
-    G: Scope,
-    G::Timestamp: Lattice,
-    Tr::KeyOwned: Ord + Hashable + ExchangeData,
+    G: Scope<Timestamp = Tr::Time>,
+    Tr::KeyOwned: Hashable + ExchangeData,
     V: ExchangeData,
     R: ExchangeData + Monoid,
-    Tr: TraceReader<Time=G::Timestamp>+Clone+'static,
-    Tr::Diff: Semigroup,
+    Tr: TraceReader+Clone+'static,
     FF: Fn(&G::Timestamp) -> G::Timestamp + 'static,
     CF: Fn(&G::Timestamp, &G::Timestamp) -> bool + 'static,
     DOut: Clone+'static,

dogsdogsdogs/src/operators/lookup_map.rs

@@ -27,9 +27,8 @@ pub fn lookup_map<G, D, R, Tr, F, DOut, ROut, S>(
     supplied_key2: Tr::KeyOwned,
 ) -> Collection<G, DOut, ROut>
 where
-    G: Scope,
-    G::Timestamp: Lattice,
-    Tr: TraceReader<Time=G::Timestamp>+Clone+'static,
+    G: Scope<Timestamp=Tr::Time>,
+    Tr: TraceReader+Clone+'static,
     Tr::KeyOwned: Hashable,
     Tr::Diff: Monoid+ExchangeData,
     F: FnMut(&D, &mut Tr::KeyOwned)+Clone+'static,

dogsdogsdogs/src/operators/propose.rs

@@ -21,9 +21,8 @@ pub fn propose<G, Tr, F, P>(
     key_selector: F,
 ) -> Collection<G, (P, Tr::ValOwned), Tr::Diff>
 where
-    G: Scope,
-    G::Timestamp: Lattice,
-    Tr: TraceReader<Time=G::Timestamp>+Clone+'static,
+    G: Scope<Timestamp=Tr::Time>,
+    Tr: TraceReader+Clone+'static,
     Tr::KeyOwned: Hashable + Default,
     Tr::Diff: Monoid+Multiply<Output = Tr::Diff>+ExchangeData,
     F: Fn(&P)->Tr::KeyOwned+Clone+'static,
@@ -51,9 +50,8 @@ pub fn propose_distinct<G, Tr, F, P>(
     key_selector: F,
 ) -> Collection<G, (P, Tr::ValOwned), Tr::Diff>
 where
-    G: Scope,
-    G::Timestamp: Lattice,
-    Tr: TraceReader<Time=G::Timestamp>+Clone+'static,
+    G: Scope<Timestamp=Tr::Time>,
+    Tr: TraceReader+Clone+'static,
     Tr::KeyOwned: Hashable + Default,
     Tr::Diff: Monoid+Multiply<Output = Tr::Diff>+ExchangeData,
     F: Fn(&P)->Tr::KeyOwned+Clone+'static,

dogsdogsdogs/src/operators/validate.rs

@@ -19,9 +19,8 @@ pub fn validate<G, K, V, Tr, F, P>(
     key_selector: F,
 ) -> Collection<G, (P, V), Tr::Diff>
 where
-    G: Scope,
-    G::Timestamp: Lattice,
-    Tr: TraceReader<KeyOwned=(K,V), ValOwned=(), Time=G::Timestamp>+Clone+'static,
+    G: Scope<Timestamp=Tr::Time>,
+    Tr: TraceReader<KeyOwned=(K,V), ValOwned=()>+Clone+'static,
     K: Ord+Hash+Clone+Default,
     V: ExchangeData+Hash+Default,
     Tr::Diff: Monoid+Multiply<Output = Tr::Diff>+ExchangeData,

examples/cursors.rs

@@ -132,10 +132,10 @@ fn main() {
 fn dump_cursor<Tr>(round: u32, index: usize, trace: &mut Tr)
 where
     Tr: TraceReader,
-    Tr::KeyOwned: Debug + Clone,
-    Tr::ValOwned: Debug + Clone,
-    Tr::Time: Debug + Clone,
-    Tr::Diff: Debug + Clone,
+    Tr::KeyOwned: Debug,
+    Tr::ValOwned: Debug,
+    Tr::Time: Debug,
+    Tr::Diff: Debug,
 {
     let (mut cursor, storage) = trace.cursor();
     for ((k, v), diffs) in cursor.to_vec(&storage).iter() {

src/algorithms/graphs/bfs.rs

@@ -26,10 +26,9 @@ use crate::operators::arrange::Arranged;
 /// Returns pairs (node, dist) indicating distance of each node from a root.
 pub fn bfs_arranged<G, N, Tr>(edges: &Arranged<G, Tr>, roots: &Collection<G, N>) -> Collection<G, (N, u32)>
 where
-    G: Scope,
-    G::Timestamp: Lattice+Ord,
+    G: Scope<Timestamp=Tr::Time>,
     N: ExchangeData+Hash,
-    Tr: for<'a> TraceReader<Key<'a>=&'a N, Val<'a>=&'a N, Time=G::Timestamp, Diff=isize>+Clone+'static,
+    Tr: for<'a> TraceReader<Key<'a>=&'a N, Val<'a>=&'a N, Diff=isize>+Clone+'static,
 {
     // initialize roots as reaching themselves at distance 0
     let nodes = roots.map(|x| (x, 0));

src/algorithms/graphs/bijkstra.rs

@@ -42,10 +42,9 @@ pub fn bidijkstra_arranged<G, N, Tr>(
     goals: &Collection<G, (N,N)>
 ) -> Collection<G, ((N,N), u32)>
 where
-    G: Scope,
-    G::Timestamp: Lattice+Ord,
+    G: Scope<Timestamp=Tr::Time>,
     N: ExchangeData+Hash,
-    Tr: for<'a> TraceReader<Key<'a>=&'a N, Val<'a>=&'a N, Time=G::Timestamp, Diff=isize>+Clone+'static,
+    Tr: for<'a> TraceReader<Key<'a>=&'a N, Val<'a>=&'a N, Diff=isize>+Clone+'static,
 {
     forward
         .stream

src/algorithms/graphs/propagate.rs

@@ -56,14 +56,13 @@ use crate::operators::arrange::arrangement::Arranged;
 /// of `logic should be a number in the interval [0,64],
 pub fn propagate_core<G, N, L, Tr, F, R>(edges: &Arranged<G,Tr>, nodes: &Collection<G,(N,L),R>, logic: F) -> Collection<G,(N,L),R>
 where
-    G: Scope,
-    G::Timestamp: Lattice+Ord,
+    G: Scope<Timestamp=Tr::Time>,
     N: ExchangeData+Hash,
     R: ExchangeData+Abelian,
     R: Multiply<R, Output=R>,
     R: From<i8>,
     L: ExchangeData,
-    Tr: for<'a> TraceReader<Key<'a>=&'a N, Val<'a>=&'a N, Time=G::Timestamp, Diff=R>+Clone+'static,
+    Tr: for<'a> TraceReader<Key<'a>=&'a N, Val<'a>=&'a N, Diff=R>+Clone+'static,
     F: Fn(&L)->u64+Clone+'static,
 {
     // Morally the code performs the following iterative computation. However, in the interest of a simplified

src/operators/arrange/agent.rs

@@ -10,7 +10,6 @@ use timely::progress::Timestamp;
 use timely::progress::{Antichain, frontier::AntichainRef};
 use timely::dataflow::operators::CapabilitySet;
 
-use crate::lattice::Lattice;
 use crate::trace::{Trace, TraceReader, Batch, BatchReader};
 use crate::trace::wrappers::rc::TraceBox;
 
@@ -29,7 +28,6 @@ use crate::trace::wrappers::frontier::{TraceFrontier, BatchFrontier};
 pub struct TraceAgent<Tr>
 where
     Tr: TraceReader,
-    Tr::Time: Lattice+Ord+Clone+'static,
 {
     trace: Rc<RefCell<TraceBox<Tr>>>,
     queues: Weak<RefCell<Vec<TraceAgentQueueWriter<Tr>>>>,
@@ -44,7 +42,6 @@ where
 impl<Tr> TraceReader for TraceAgent<Tr>
 where
     Tr: TraceReader,
-    Tr::Time: Lattice+Ord+Clone+'static,
 {
     type Key<'a> = Tr::Key<'a>;
     type KeyOwned = Tr::KeyOwned;
@@ -85,11 +82,7 @@ where
     fn map_batches<F: FnMut(&Self::Batch)>(&self, f: F) { self.trace.borrow().trace.map_batches(f) }
 }
 
-impl<Tr> TraceAgent<Tr>
-where
-    Tr: TraceReader,
-    Tr::Time: Timestamp+Lattice,
-{
+impl<Tr: TraceReader> TraceAgent<Tr> {
     /// Creates a new agent from a trace reader.
     pub fn new(trace: Tr, operator: OperatorInfo, logging: Option<crate::logging::Logger>) -> (Self, TraceWriter<Tr>)
     where
@@ -177,7 +170,6 @@ where
 impl<Tr> TraceAgent<Tr>
 where
     Tr: TraceReader+'static,
-    Tr::Time: Lattice+Ord+Clone+'static,
 {
     /// Copies an existing collection into the supplied scope.
     ///
@@ -233,7 +225,6 @@ where
     pub fn import<G>(&mut self, scope: &G) -> Arranged<G, TraceAgent<Tr>>
     where
         G: Scope<Timestamp=Tr::Time>,
-        Tr::Time: Timestamp,
     {
         self.import_named(scope, "ArrangedSource")
     }
@@ -242,7 +233,6 @@ where
     pub fn import_named<G>(&mut self, scope: &G, name: &str) -> Arranged<G, TraceAgent<Tr>>
     where
         G: Scope<Timestamp=Tr::Time>,
-        Tr::Time: Timestamp,
     {
         // Drop ShutdownButton and return only the arrangement.
         self.import_core(scope, name).0
@@ -300,7 +290,6 @@ where
     pub fn import_core<G>(&mut self, scope: &G, name: &str) -> (Arranged<G, TraceAgent<Tr>>, ShutdownButton<CapabilitySet<Tr::Time>>)
     where
         G: Scope<Timestamp=Tr::Time>,
-        Tr::Time: Timestamp,
     {
         let trace = self.clone();
 
@@ -418,7 +407,6 @@ where
     pub fn import_frontier<G>(&mut self, scope: &G, name: &str) -> (Arranged<G, TraceFrontier<TraceAgent<Tr>>>, ShutdownButton<CapabilitySet<Tr::Time>>)
     where
         G: Scope<Timestamp=Tr::Time>,
-        Tr::Time: Timestamp+ Lattice+Ord+Clone+'static,
         Tr: TraceReader,
     {
         // This frontier describes our only guarantee on the compaction frontier.
@@ -437,7 +425,6 @@ where
     pub fn import_frontier_core<G>(&mut self, scope: &G, name: &str, since: Antichain<Tr::Time>, until: Antichain<Tr::Time>) -> (Arranged<G, TraceFrontier<TraceAgent<Tr>>>, ShutdownButton<CapabilitySet<Tr::Time>>)
     where
         G: Scope<Timestamp=Tr::Time>,
-        Tr::Time: Timestamp+ Lattice+Ord+Clone+'static,
         Tr: TraceReader,
     {
         let trace = self.clone();
@@ -541,7 +528,6 @@ impl<T> Drop for ShutdownDeadmans<T> {
 impl<Tr> Clone for TraceAgent<Tr>
 where
     Tr: TraceReader,
-    Tr::Time: Lattice+Ord+Clone+'static,
 {
     fn clone(&self) -> Self {
 
@@ -571,7 +557,6 @@ where
 impl<Tr> Drop for TraceAgent<Tr>
 where
     Tr: TraceReader,
-    Tr::Time: Lattice+Ord+Clone+'static,
 {
     fn drop(&mut self) {