From 5caccbaf50d0177e548b4f3b03233369c91e6ede Mon Sep 17 00:00:00 2001
From: asteri <astridklipfel@gmail.com>
Date: Tue, 28 Apr 2026 17:29:11 +0200
Subject: [PATCH] improve var creation for SumProdCircuit

---
 examples/dag.rs              | 10 +++++-----
 examples/quotient.rs         |  1 +
 src/circuit/dag.rs           |  2 +-
 src/circuit/probabilistic.rs |  2 +-
 src/circuit/quotient.rs      |  2 +-
 src/circuit/traits.rs        |  6 +++---
 6 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/examples/dag.rs b/examples/dag.rs
index a5443e6..2530dc0 100644
--- a/examples/dag.rs
+++ b/examples/dag.rs
@@ -6,10 +6,10 @@ use circuit_cas::circuit::dag::CircuitExt;
 fn main() {
     let circuit: Rc<RefCell<ProbCircuit>> = ProbCircuit::new();
 
-    // Build (x + y) * (x + z)
-    let x = circuit.var("x");
-    let y = circuit.var("y");
-    let z = circuit.var("z");
+    // vars accept anything that implements Into<StaticVar>: &'static str, (&str, u32), (&str, u32, u32)
+    let x   = circuit.var("x");
+    let y   = circuit.var(("y", 1));       // indexed variable y_1
+    let z   = circuit.var(("z", 0, 1));    // doubly-indexed variable z_{0,1}
 
     let x_plus_y = circuit.var("x") + y;
     let x_plus_z = circuit.var("x") + z;
@@ -19,7 +19,7 @@ fn main() {
     let x2 = circuit.var("x");
     assert_eq!(x.id, x2.id);
 
-    println!("(x + y) * (x + z) root node id: {:?}", expr.id);
+    println!("(x + y_1) * (x + z_{{0,1}}) root node id: {:?}", expr.id);
     println!("x node id: {:?}", x.id);
     println!("x deduplicated node id: {:?}", x2.id);
 }
diff --git a/examples/quotient.rs b/examples/quotient.rs
index 66c09f9..c045c6b 100644
--- a/examples/quotient.rs
+++ b/examples/quotient.rs
@@ -19,6 +19,7 @@ fn main() {
     let quotient: Rc<RefCell<QuotientCircuit>> = idem.into();
 
     // Build x * x̄ + x in the DAG
+    // var accepts anything that implements Into<StaticVar>: &'static str, (&str, u32), (&str, u32, u32)
     let xn   = quotient.var("x");
     let nxn  = quotient.var("x\u{0304}");
     let prod = xn * nxn;
diff --git a/src/circuit/dag.rs b/src/circuit/dag.rs
index 49fe59e..000703f 100644
--- a/src/circuit/dag.rs
+++ b/src/circuit/dag.rs
@@ -60,5 +60,5 @@ pub struct RefNode<C: Circuit> {
 pub trait CircuitExt {
     type C: Circuit;
     type Var;
-    fn var(&self, v: impl Into<Self::Var>) -> RefNode<Self::C>;
+    fn var<T: Into<Self::Var>>(&self, v: T) -> RefNode<Self::C>;
 }
diff --git a/src/circuit/probabilistic.rs b/src/circuit/probabilistic.rs
index 4e92dd3..a15c621 100644
--- a/src/circuit/probabilistic.rs
+++ b/src/circuit/probabilistic.rs
@@ -43,7 +43,7 @@ impl<V: Var> ProbCircuit<V> {
 impl<V: Var> SumProdCircuit for ProbCircuit<V> {
     type Var = V;
 
-    fn var(&mut self, v: V) -> NodeId { self.node(PNode::Var(v)) }
+    fn var<T: Into<V>>(&mut self, v: T) -> NodeId { self.node(PNode::Var(v.into())) }
 
     fn add(&mut self, l: NodeId, r: NodeId) -> NodeId {
         let (l, r) = if l <= r { (l, r) } else { (r, l) };
diff --git a/src/circuit/quotient.rs b/src/circuit/quotient.rs
index d216f33..b88e04e 100644
--- a/src/circuit/quotient.rs
+++ b/src/circuit/quotient.rs
@@ -57,7 +57,7 @@ impl<V: Var> DerefMut for QuotientCircuit<V> {
 impl<V: Var> SumProdCircuit for QuotientCircuit<V> {
     type Var = V;
 
-    fn var(&mut self, v: V) -> NodeId { self.node(QNode::Var(v)) }
+    fn var<T: Into<V>>(&mut self, v: T) -> NodeId { self.node(QNode::Var(v.into())) }
 
     fn add(&mut self, l: NodeId, r: NodeId) -> NodeId {
         let (l, r) = if l <= r { (l, r) } else { (r, l) };
diff --git a/src/circuit/traits.rs b/src/circuit/traits.rs
index 60f5e88..aa79281 100644
--- a/src/circuit/traits.rs
+++ b/src/circuit/traits.rs
@@ -29,7 +29,7 @@ where
 
 pub trait SumProdCircuit: Circuit {
     type Var;
-    fn var(&mut self, v: Self::Var) -> NodeId;
+    fn var<T: Into<Self::Var>>(&mut self, v: T) -> NodeId;
     fn add(&mut self, l: NodeId, r: NodeId) -> NodeId;
     fn mul(&mut self, l: NodeId, r: NodeId) -> NodeId;
 }
@@ -56,8 +56,8 @@ impl<C: SumProdCircuit> CircuitExt for Rc<RefCell<C>> {
     type C = C;
     type Var = C::Var;
 
-    fn var(&self, v: impl Into<C::Var>) -> RefNode<C> {
-        let id = self.borrow_mut().var(v.into());
+    fn var<T: Into<C::Var>>(&self, v: T) -> RefNode<C> {
+        let id = self.borrow_mut().var(v);
         RefNode { id, circuit: self.clone() }
     }
 }