feat!: Let Hugr implement Circuit (#91)

- Replaces the `HierarchyView` bound in `Circuit` with `HugrView` (from
CQCL/hugr#498), which is implemented by
`Hugr`.
- This simplifies the tests, where we don't need to wrap `Hugr`s
anymore.
- We still need a lifetime for the Commands iterator, so
`Circuit::Comands` now has a generic lifetime.
- Uses the new `PetgraphWrapper` when needed instead of requiring
Petgraph traits on everything.
    - This lets us drop the lifetime from `Circuit<'a>`.

Closes #84.
~Blocked by CQCL/hugr#498

Cargo.toml

@@ -69,7 +69,7 @@ members = ["pyrs", "compile-matcher"]
 
 [workspace.dependencies]
 
-quantinuum-hugr = { git = "https://github.com/CQCL-DEV/hugr", rev = "5a97a635" }
+quantinuum-hugr = { git = "https://github.com/CQCL-DEV/hugr", rev = "e23323d" }
 portgraph = { version = "0.9", features = ["serde"] }
 pyo3 = { version = "0.19" }
 itertools = { version = "0.11.0" }

benches/benchmarks/hash.rs

@@ -1,7 +1,7 @@
 use criterion::{black_box, criterion_group, AxisScale, BenchmarkId, Criterion, PlotConfiguration};
-use hugr::hugr::views::SiblingGraph;
+use hugr::hugr::views::{HierarchyView, SiblingGraph};
 use hugr::HugrView;
-use tket2::circuit::{CircuitHash, HierarchyView};
+use tket2::circuit::CircuitHash;
 
 use super::generators::make_cnot_layers;
 

compile-matcher/src/main.rs

@@ -2,7 +2,7 @@ use std::fs;
 use std::path::Path;
 
 use clap::Parser;
-use hugr::hugr::views::{HierarchyView, SiblingGraph};
+use hugr::hugr::views::SiblingGraph;
 use hugr::ops::handle::DfgID;
 use hugr::HugrView;
 use itertools::Itertools;

src/circuit.rs

@@ -18,12 +18,10 @@ use hugr::hugr::{CircuitUnit, NodeType};
 use hugr::ops::OpTrait;
 use hugr::HugrView;
 
-pub use hugr::hugr::views::HierarchyView;
 pub use hugr::ops::OpType;
 use hugr::types::TypeBound;
 pub use hugr::types::{EdgeKind, Signature, Type, TypeRow};
 pub use hugr::{Node, Port, Wire};
-use petgraph::visit::{GraphBase, IntoNeighborsDirected, IntoNodeIdentifiers};
 
 /// An object behaving like a quantum circuit.
 //
@@ -32,9 +30,11 @@ use petgraph::visit::{GraphBase, IntoNeighborsDirected, IntoNodeIdentifiers};
 // - Vertical slice iterator
 // - Gate count map
 // - Depth
-pub trait Circuit<'circ>: HugrView {
+pub trait Circuit: HugrView {
     /// An iterator over the commands in the circuit.
-    type Commands: Iterator<Item = Command>;
+    type Commands<'a>: Iterator<Item = Command>
+    where
+        Self: 'a;
 
     /// An iterator over the commands applied to an unit.
     type UnitCommands: Iterator<Item = Command>;
@@ -67,10 +67,10 @@ pub trait Circuit<'circ>: HugrView {
     /// Returns all the commands in the circuit, in some topological order.
     ///
     /// Ignores the Input and Output nodes.
-    fn commands(&'circ self) -> Self::Commands;
+    fn commands(&self) -> Self::Commands<'_>;
 
     /// Returns all the commands applied to the given unit, in order.
-    fn unit_commands(&'circ self) -> Self::UnitCommands;
+    fn unit_commands(&self) -> Self::UnitCommands;
 
     /// Returns the [`NodeType`] of a command.
     fn command_nodetype(&self, command: &Command) -> &NodeType {
@@ -86,12 +86,11 @@ pub trait Circuit<'circ>: HugrView {
     fn num_gates(&self) -> usize;
 }
 
-impl<'circ, T> Circuit<'circ> for T
+impl<T> Circuit for T
 where
-    T: 'circ + HierarchyView<'circ>,
-    for<'a> &'a T: GraphBase<NodeId = Node> + IntoNeighborsDirected + IntoNodeIdentifiers,
+    T: HugrView,
 {
-    type Commands = CommandIterator<'circ, T>;
+    type Commands<'a> = CommandIterator<'a, T> where Self: 'a;
     type UnitCommands = std::iter::Empty<Command>;
 
     #[inline]
@@ -129,12 +128,12 @@ where
         }
     }
 
-    fn commands(&'circ self) -> Self::Commands {
+    fn commands(&self) -> Self::Commands<'_> {
         // Traverse the circuit in topological order.
         CommandIterator::new(self)
     }
 
-    fn unit_commands(&'circ self) -> Self::UnitCommands {
+    fn unit_commands(&self) -> Self::UnitCommands {
         // TODO Can we associate linear i/o with the corresponding unit without
         // doing the full toposort?
         unimplemented!()
@@ -158,35 +157,24 @@ where
 
 #[cfg(test)]
 mod tests {
-    use std::sync::OnceLock;
-
-    use hugr::{
-        hugr::views::{DescendantsGraph, HierarchyView},
-        ops::handle::DfgID,
-        Hugr, HugrView,
-    };
+    use hugr::Hugr;
 
     use crate::{circuit::Circuit, json::load_tk1_json_str};
 
-    static CIRC: OnceLock<Hugr> = OnceLock::new();
-
-    fn test_circuit() -> DescendantsGraph<'static, DfgID> {
-        let hugr = CIRC.get_or_init(|| {
-            load_tk1_json_str(
-                r#"{
-                "phase": "0",
-                "bits": [],
-                "qubits": [["q", [0]], ["q", [1]]],
-                "commands": [
-                    {"args": [["q", [0]]], "op": {"type": "H"}},
-                    {"args": [["q", [0]], ["q", [1]]], "op": {"type": "CX"}}
-                ],
-                "implicit_permutation": [[["q", [0]], ["q", [0]]], [["q", [1]], ["q", [1]]]]
-            }"#,
-            )
-            .unwrap()
-        });
-        DescendantsGraph::new(hugr, hugr.root())
+    fn test_circuit() -> Hugr {
+        load_tk1_json_str(
+            r#"{
+            "phase": "0",
+            "bits": [],
+            "qubits": [["q", [0]], ["q", [1]]],
+            "commands": [
+                {"args": [["q", [0]]], "op": {"type": "H"}},
+                {"args": [["q", [0]], ["q", [1]]], "op": {"type": "CX"}}
+            ],
+            "implicit_permutation": [[["q", [0]], ["q", [0]]], [["q", [1]], ["q", [1]]]]
+        }"#,
+        )
+        .unwrap()
     }
 
     #[test]

src/circuit/command.rs

@@ -5,9 +5,7 @@
 use std::collections::HashMap;
 use std::iter::FusedIterator;
 
-use hugr::hugr::views::HierarchyView;
 use hugr::ops::{OpTag, OpTrait};
-use petgraph::visit::{GraphBase, IntoNeighborsDirected, IntoNodeIdentifiers};
 
 use super::Circuit;
 
@@ -59,8 +57,7 @@ pub struct CommandIterator<'circ, Circ> {
 
 impl<'circ, Circ> CommandIterator<'circ, Circ>
 where
-    Circ: HierarchyView<'circ>,
-    for<'a> &'a Circ: GraphBase<NodeId = Node> + IntoNeighborsDirected + IntoNodeIdentifiers,
+    Circ: Circuit,
 {
     /// Create a new iterator over the commands of a circuit.
     pub(super) fn new(circ: &'circ Circ) -> Self {
@@ -77,7 +74,7 @@ where
             })
             .collect();
 
-        let nodes = petgraph::algo::toposort(circ, None).unwrap();
+        let nodes = petgraph::algo::toposort(&circ.as_petgraph(), None).unwrap();
         Self {
             circ,
             nodes,
@@ -157,8 +154,7 @@ where
 
 impl<'circ, Circ> Iterator for CommandIterator<'circ, Circ>
 where
-    Circ: HierarchyView<'circ>,
-    for<'a> &'a Circ: GraphBase<NodeId = Node> + IntoNeighborsDirected + IntoNodeIdentifiers,
+    Circ: Circuit,
 {
     type Item = Command;
 
@@ -182,12 +178,7 @@ where
     }
 }
 
-impl<'circ, Circ> FusedIterator for CommandIterator<'circ, Circ>
-where
-    Circ: HierarchyView<'circ>,
-    for<'a> &'a Circ: GraphBase<NodeId = Node> + IntoNeighborsDirected + IntoNodeIdentifiers,
-{
-}
+impl<'circ, Circ> FusedIterator for CommandIterator<'circ, Circ> where Circ: Circuit {}
 
 #[cfg(test)]
 mod test {

src/circuit/hash.rs

@@ -4,7 +4,6 @@ use core::panic;
 use std::hash::{Hash, Hasher};
 
 use fxhash::{FxHashMap, FxHasher64};
-use hugr::hugr::views::HierarchyView;
 use hugr::ops::{LeafOp, OpName, OpTag, OpTrait, OpType};
 use hugr::types::TypeBound;
 use hugr::{HugrView, Node, Port};
@@ -29,14 +28,15 @@ pub trait CircuitHash<'circ>: HugrView {
 
 impl<'circ, T> CircuitHash<'circ> for T
 where
-    T: HugrView + HierarchyView<'circ>,
-    for<'a> &'a T:
-        pg::GraphBase<NodeId = Node> + pg::IntoNeighborsDirected + pg::IntoNodeIdentifiers,
+    T: HugrView,
 {
     fn circuit_hash(&'circ self) -> u64 {
         let mut hash_state = HashState::default();
 
-        for node in pg::Topo::new(self).iter(self).filter(|&n| n != self.root()) {
+        for node in pg::Topo::new(&self.as_petgraph())
+            .iter(&self.as_petgraph())
+            .filter(|&n| n != self.root())
+        {
             let hash = hash_node(self, node, &mut hash_state);
             hash_state.set_node(self, node, hash);
         }

src/json.rs

@@ -38,7 +38,7 @@ pub trait TKETDecode: Sized {
     /// Convert the serialized circuit to a [`Hugr`].
     fn decode(self) -> Result<Hugr, Self::DecodeError>;
     /// Convert a [`Hugr`] to a new serialized circuit.
-    fn encode<'circ>(circuit: &'circ impl Circuit<'circ>) -> Result<Self, Self::EncodeError>;
+    fn encode(circuit: &impl Circuit) -> Result<Self, Self::EncodeError>;
 }
 
 impl TKETDecode for SerialCircuit {
@@ -60,7 +60,7 @@ impl TKETDecode for SerialCircuit {
         Ok(decoder.finish())
     }
 
-    fn encode<'circ>(circ: &'circ impl Circuit<'circ>) -> Result<Self, Self::EncodeError> {
+    fn encode(circ: &impl Circuit) -> Result<Self, Self::EncodeError> {
         let mut encoder = JsonEncoder::new(circ);
         for com in circ.commands() {
             let optype = circ.command_optype(&com);

src/json/encoder.rs

@@ -40,7 +40,7 @@ pub(super) struct JsonEncoder {
 
 impl JsonEncoder {
     /// Create a new [`JsonEncoder`] from a [`Circuit`].
-    pub fn new<'circ>(circ: &impl Circuit<'circ>) -> Self {
+    pub fn new(circ: &impl Circuit) -> Self {
         let name = circ.name().map(str::to_string);
 
         // Compute the linear qubit and bit registers. Each one have independent

src/ops.rs

@@ -289,12 +289,8 @@ pub(crate) mod test {
 
     use std::sync::Arc;
 
-    use hugr::{
-        extension::OpDef,
-        hugr::views::{HierarchyView, SiblingGraph},
-        ops::handle::DfgID,
-        Hugr, HugrView,
-    };
+    use hugr::hugr::views::HierarchyView;
+    use hugr::{extension::OpDef, hugr::views::SiblingGraph, ops::handle::DfgID, Hugr, HugrView};
     use rstest::{fixture, rstest};
 
     use crate::{circuit::Circuit, ops::SimpleOpEnum, utils::build_simple_circuit};

src/portmatching/matcher.rs

@@ -73,7 +73,7 @@ pub struct PatternMatch<'a, C> {
     pub(super) root: Node,
 }
 
-impl<'a, C: Circuit<'a> + Clone> PatternMatch<'a, C> {
+impl<'a, C: Circuit + Clone> PatternMatch<'a, C> {
     /// The matcher's pattern ID of the match.
     pub fn pattern_id(&self) -> PatternID {
         self.pattern
@@ -187,7 +187,7 @@ impl<'a, C: Circuit<'a> + Clone> PatternMatch<'a, C> {
     }
 }
 
-impl<'a, C: Circuit<'a>> Debug for PatternMatch<'a, C> {
+impl<'a, C: Circuit> Debug for PatternMatch<'a, C> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         f.debug_struct("PatternMatch")
             .field("root", &self.root)
@@ -237,10 +237,7 @@ impl PatternMatcher {
     }
 
     /// Find all convex pattern matches in a circuit.
-    pub fn find_matches<'a, C: Circuit<'a> + Clone>(
-        &self,
-        circuit: &'a C,
-    ) -> Vec<PatternMatch<'a, C>> {
+    pub fn find_matches<'a, C: Circuit + Clone>(&self, circuit: &'a C) -> Vec<PatternMatch<'a, C>> {
         let mut checker = ConvexChecker::new(circuit);
         circuit
             .commands()
@@ -249,7 +246,7 @@ impl PatternMatcher {
     }
 
     /// Find all convex pattern matches in a circuit rooted at a given node.
-    fn find_rooted_matches<'a, C: Circuit<'a> + Clone>(
+    fn find_rooted_matches<'a, C: Circuit + Clone>(
         &self,
         circ: &'a C,
         root: Node,
@@ -385,8 +382,8 @@ fn compatible_offsets((_, pout): &(Port, Port), (pin, _): &(Port, Port)) -> bool
 }
 
 /// Check if an edge `e` is valid in a portgraph `g` without weights.
-pub(crate) fn validate_unweighted_edge<'circ>(
-    circ: &impl Circuit<'circ>,
+pub(crate) fn validate_unweighted_edge(
+    circ: &impl Circuit,
 ) -> impl for<'a> Fn(Node, &'a PEdge) -> Option<Node> + '_ {
     move |src, &(src_port, tgt_port)| {
         let (next_node, _) = circ
@@ -397,8 +394,8 @@ pub(crate) fn validate_unweighted_edge<'circ>(
 }
 
 /// Check if a node `n` is valid in a weighted portgraph `g`.
-pub(crate) fn validate_weighted_node<'circ>(
-    circ: &impl Circuit<'circ>,
+pub(crate) fn validate_weighted_node(
+    circ: &impl Circuit,
 ) -> impl for<'a> Fn(Node, &PNode) -> bool + '_ {
     move |v, prop| {
         let v_weight = MatchOp::try_from(circ.get_optype(v).clone());
@@ -425,43 +422,30 @@ fn handle_match_error<T>(match_res: Result<T, InvalidPatternMatch>, root: Node)
 
 #[cfg(test)]
 mod tests {
-    use std::sync::OnceLock;
-
-    use hugr::hugr::views::{DescendantsGraph, HierarchyView};
-    use hugr::ops::handle::DfgID;
-    use hugr::{Hugr, HugrView};
+    use hugr::Hugr;
     use itertools::Itertools;
 
     use crate::utils::build_simple_circuit;
     use crate::T2Op;
 
     use super::{CircuitPattern, PatternMatcher};
 
-    static H_CX: OnceLock<Hugr> = OnceLock::new();
-    static CX_CX: OnceLock<Hugr> = OnceLock::new();
-
-    fn h_cx<'a>() -> DescendantsGraph<'a, DfgID> {
-        let circ = H_CX.get_or_init(|| {
-            build_simple_circuit(2, |circ| {
-                circ.append(T2Op::CX, [0, 1]).unwrap();
-                circ.append(T2Op::H, [0]).unwrap();
-                Ok(())
-            })
-            .unwrap()
-        });
-        DescendantsGraph::new(circ, circ.root())
+    fn h_cx() -> Hugr {
+        build_simple_circuit(2, |circ| {
+            circ.append(T2Op::CX, [0, 1]).unwrap();
+            circ.append(T2Op::H, [0]).unwrap();
+            Ok(())
+        })
+        .unwrap()
     }
 
-    fn cx_xc<'a>() -> DescendantsGraph<'a, DfgID> {
-        let circ = CX_CX.get_or_init(|| {
-            build_simple_circuit(2, |circ| {
-                circ.append(T2Op::CX, [0, 1]).unwrap();
-                circ.append(T2Op::CX, [1, 0]).unwrap();
-                Ok(())
-            })
-            .unwrap()
-        });
-        DescendantsGraph::new(circ, circ.root())
+    fn cx_xc() -> Hugr {
+        build_simple_circuit(2, |circ| {
+            circ.append(T2Op::CX, [0, 1]).unwrap();
+            circ.append(T2Op::CX, [1, 0]).unwrap();
+            Ok(())
+        })
+        .unwrap()
     }
 
     #[test]