fix: cast node.size to IntegerLiteral for qubit register size (#258)

Fixes bug [#240] by casting node.size into IntegerLiteral

Author: EuGig

src/braket/default_simulator/openqasm/_helpers/functions.py

@@ -98,10 +98,16 @@
             [BooleanLiteral(xv.value ^ yv.value) for xv, yv in zip(x.values, y.values)]
         ),
         getattr(BinaryOperator, "<<"): lambda x, y: ArrayLiteral(
-            x.values[y.value :] + [BooleanLiteral(False) for _ in range(y.value)]
+            x.values[len(y.values) :] + [BooleanLiteral(False) for _ in range(len(y.values))]
+            if isinstance(y, ArrayLiteral)
+            else x.values[y.value :] + [BooleanLiteral(False) for _ in range(y.value)]
         ),
         getattr(BinaryOperator, ">>"): lambda x, y: ArrayLiteral(
-            [BooleanLiteral(False) for _ in range(y.value)] + x.values[: len(x.values) - y.value]
+            [BooleanLiteral(False) for _ in range(len(y.values))]
+            + x.values[: len(x.values) - len(y.values)]
+            if isinstance(y, ArrayLiteral)
+            else [BooleanLiteral(False) for _ in range(y.value)]
+            + x.values[: len(x.values) - y.value]
         ),
         getattr(UnaryOperator, "~"): lambda x: ArrayLiteral(
             [BooleanLiteral(not v.value) for v in x.values]

src/braket/default_simulator/openqasm/interpreter.py

@@ -247,8 +247,13 @@ def _(self, node: Identifier) -> LiteralType:
 
     @visit.register
     def _(self, node: QubitDeclaration) -> None:
-        size = self.visit(node.size).value if node.size else 1
-        self.context.add_qubits(node.qubit.name, size)
+        size_arg = self.visit(node.size)
+        if isinstance(size_arg, ArrayLiteral) and size_arg:
+            size = "".join(str(cast_to(IntegerLiteral, qubit).value) for qubit in size_arg.values)
+            self.context.add_qubits(node.qubit.name, int(size, 2))
+        else:
+            size = size_arg.value if size_arg else 1
+            self.context.add_qubits(node.qubit.name, size)
 
     @visit.register
     def _(self, node: QuantumReset) -> None:

test/unit_tests/braket/default_simulator/openqasm/test_interpreter.py

@@ -2207,3 +2207,77 @@ def test_measure_invalid_qubit():
 def test_measure_qubit_out_of_range(qasm, expected):
     with pytest.raises(IndexError, match=expected):
         Interpreter().build_circuit(qasm)
+
+
+@pytest.mark.parametrize(
+    "qasm, expected",
+    [
+        (
+            """
+                bit[2] b;
+                qubit["10"] r1;
+                b = measure r1;
+            """,
+            [0, 1],
+        ),
+        (
+            """
+                bit[3] b;
+                qubit["11"] r1;
+                b = measure r1;
+            """,
+            [0, 1, 2],
+        ),
+        (
+            """
+                bit[1] b;
+                qubit[!"1"] r1;
+                b = measure r1;
+            """,
+            [],
+        ),
+        (
+            """
+                qubit["1" ^ "0"] r1;
+            """,
+            [],
+        ),
+        (
+            """
+                bit[1] b;
+                qubit["1" != "0"] r1;
+                b = measure r1;
+            """,
+            [0],
+        ),
+        (
+            """
+                bit[1] b;
+                qubit["1" == "0"] r1;
+                b = measure r1;
+            """,
+            [],
+        ),
+        (
+            """
+                bit[1] b;
+                qubit[1] r1;
+                h r1["0" << "1"];
+                b = measure r1;
+            """,
+            [0],
+        ),
+        (
+            """
+                bit[2] b;
+                qubit[1] r1;
+                h r1["0" >> "1"];
+                b = measure r1;
+            """,
+            [0],
+        ),
+    ],
+)
+def test_circuit_from_string_literal(qasm, expected):
+    circ = Interpreter().build_circuit(source=qasm)
+    assert expected == circ.measured_qubits