[fix] two-qubit gates with qubit ranges

src/tequila-impl.typ

@@ -26,11 +26,12 @@
   if type(control) == int { control = (control,) }
   if type(target) == int { target = (target,) }
 
-  for c in control {
-    for t in target {
-      assert.ne(t, c, message: "Target and control qubit cannot be the same")
-      gates.push(bgate(c, start, nq: t - c + 1, end: end, t - c) )
-    }
+  for i in range(calc.max(control.len(), target.len())) {
+    let c = control.at(i, default: control.last())
+    let t = target.at(i, default: target.last())
+    assert.ne(t, c, message: "Target and control qubit cannot be the same")
+    gates.push(bgate(c, start, nq: t - c + 1, end: end, t - c) )
+
   }
   gates
 }

tests/tequila/basic/test.typ

@@ -1,5 +1,6 @@
 #set page(width: auto, height: auto, margin: 0pt)
-#import "/src/quill.typ" as quill: tequila as tq
+#import "/src/quill.typ"
+#import quill: tequila as tq
 
 #quill.quantum-circuit(
   ..tq.build(

tests/tequila/ranges-with-two-qubit-gates/test.typ

@@ -0,0 +1,11 @@
+#set page(width: auto, height: auto, margin: 0pt)
+#import "/src/quill.typ"
+#import quill: tequila as tq
+
+#quill.quantum-circuit(
+  ..tq.build(
+    tq.cx((0, 1), (1, 2)),
+    tq.cx(0, (1,2)),
+    tq.cx((1, 2), 0),
+  )
+)