Add leakage to the CLI

Author: david-pl

crates/ppvm-tui/src/app.rs

@@ -471,6 +471,7 @@ Gates  (q = qubit index; angles / probabilities are floats)
   u3 <q> <theta> <phi> <lam>
   rxx ryy rzz <a> <b> <angle>
   depolarize loss <q> <p>     depolarize2 <a> <b> <p>
+  leakage <q> <p0> <p1>
   pauli_error <q> <px> <py> <pz>     correlated_loss <a> <b> <p0> <p1> <p2>
 
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crates/ppvm-tui/src/command.rs

@@ -50,6 +50,9 @@ pub fn gate_spec(name: &str) -> Option<GateSpec> {
         "loss" => (Loss, 1, 1),
         "pauli_error" => (PauliError, 1, 3),
         "correlated_loss" => (CorrelatedLoss, 2, 3),
+        // Same shape as `r`: one qubit, two floats. Push order is q, p0, p1
+        // (probabilities of leaking into pinned |0⟩ / |1⟩).
+        "leakage" => (Leakage, 1, 2),
         _ => return None,
     };
     Some(GateSpec {
@@ -208,6 +211,20 @@ mod tests {
         );
     }
 
+    #[test]
+    fn leakage_parses_qubit_and_two_probs() {
+        assert_eq!(
+            parse_command("leakage 0 0.0 1.0").unwrap(),
+            Command::Gate {
+                inst: CircuitInstruction::Leakage,
+                qubits: vec![0],
+                params: vec![0.0, 1.0],
+            }
+        );
+        assert!(parse_command("leakage 0 1.0").is_err());
+        assert!(parse_command("leakage 0").is_err());
+    }
+
     #[test]
     fn meta_commands() {
         assert_eq!(parse_command(":q").unwrap(), Command::Quit);