fix: Support angle declarations (#199)

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

@@ -1,3 +1,16 @@
+# Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"). You
+# may not use this file except in compliance with the License. A copy of
+# the License is located at
+#
+#     http://aws.amazon.com/apache2.0/
+#
+# or in the "license" file accompanying this file. This file is
+# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
+# ANY KIND, either express or implied. See the License for the specific
+# language governing permissions and limitations under the License.
+
 from functools import singledispatch
 from typing import List, Optional, Type, Union
 

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

@@ -1,3 +1,16 @@
+# Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"). You
+# may not use this file except in compliance with the License. A copy of
+# the License is located at
+#
+#     http://aws.amazon.com/apache2.0/
+#
+# or in the "license" file accompanying this file. This file is
+# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
+# ANY KIND, either express or implied. See the License for the specific
+# language governing permissions and limitations under the License.
+
 import warnings
 from copy import deepcopy
 from functools import singledispatch
@@ -7,6 +20,7 @@
 from sympy import Symbol
 
 from ..parser.openqasm_ast import (
+    AngleType,
     ArrayLiteral,
     ArrayType,
     BitstringLiteral,
@@ -103,14 +117,21 @@ def _(into: UintType, variable: LiteralType) -> IntegerLiteral:
 def _(into: FloatType, variable: LiteralType) -> FloatLiteral:
     """Cast to float"""
     if into.size is None:
-        value = float(variable.value)
-    else:
-        if into.size.value not in (16, 32, 64):
-            raise ValueError("Float size must be one of {16, 32, 64}.")
-        value = float(np.array(variable.value, dtype=np.dtype(f"float{into.size.value}")))
+        return FloatLiteral(float(variable.value))
+    if into.size.value not in (16, 32, 64):
+        raise ValueError("Float size must be one of {16, 32, 64}.")
+    value = float(np.array(variable.value, dtype=np.dtype(f"float{into.size.value}")))
     return FloatLiteral(value)
 
 
+@cast_to.register
+def _(into: AngleType, variable: LiteralType) -> FloatLiteral:
+    """Cast angle to float"""
+    if into.size is None:
+        return FloatLiteral(float(variable.value) % (2 * np.pi))
+    raise ValueError("Fixed-bit angles are not supported.")
+
+
 @cast_to.register
 def _(into: ArrayType, variable: Union[ArrayLiteral, DiscreteSet]) -> ArrayLiteral:
     """Cast to Array and enforce dimensions"""

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

@@ -1,3 +1,16 @@
+# Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"). You
+# may not use this file except in compliance with the License. A copy of
+# the License is located at
+#
+#     http://aws.amazon.com/apache2.0/
+#
+# or in the "license" file accompanying this file. This file is
+# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
+# ANY KIND, either express or implied. See the License for the specific
+# language governing permissions and limitations under the License.
+
 """
 Evaluating expressions
 """

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

@@ -1,3 +1,16 @@
+# Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License"). You
+# may not use this file except in compliance with the License. A copy of
+# the License is located at
+#
+#     http://aws.amazon.com/apache2.0/
+#
+# or in the "license" file accompanying this file. This file is
+# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
+# ANY KIND, either express or implied. See the License for the specific
+# language governing permissions and limitations under the License.
+
 from typing import List, Union
 
 from ..parser.openqasm_ast import (

src/braket/default_simulator/openqasm/interpreter.py

@@ -100,7 +100,7 @@
     WhileLoop,
 )
 from .parser.openqasm_parser import parse
-from .program_context import ProgramContext
+from .program_context import AbstractProgramContext, ProgramContext
 
 
 class Interpreter:
@@ -114,7 +114,9 @@ class Interpreter:
     the ProgramContext object, which can be used for debugging or other customizability.
     """
 
-    def __init__(self, context: Optional[ProgramContext] = None, logger: Optional[Logger] = None):
+    def __init__(
+        self, context: Optional[AbstractProgramContext] = None, logger: Optional[Logger] = None
+    ):
         # context keeps track of all state
         self.context = context or ProgramContext()
         self.logger = logger or getLogger(__name__)

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

@@ -44,6 +44,7 @@
 from braket.default_simulator.openqasm.circuit import Circuit
 from braket.default_simulator.openqasm.interpreter import Interpreter
 from braket.default_simulator.openqasm.parser.openqasm_ast import (
+    AngleType,
     ArrayLiteral,
     ArrayType,
     BitstringLiteral,
@@ -193,6 +194,31 @@ def test_float_declaration():
     assert context.get_value("unsized") == FloatLiteral(np.pi)
 
 
+def test_angle_declaration():
+    qasm = """
+    angle uninitialized;
+    angle pos = 3.5 * π;
+    angle neg = -4.5 * π;
+    """
+    context = Interpreter().run(qasm)
+
+    assert context.get_type("uninitialized") == AngleType(None)
+    assert context.get_type("pos") == AngleType(None)
+    assert context.get_type("neg") == AngleType(None)
+
+    assert context.get_value("uninitialized") is None
+    assert context.get_value("pos") == FloatLiteral(1.5 * np.pi)
+    assert context.get_value("neg") == FloatLiteral(1.5 * np.pi)
+
+
+def test_fixed_bit_angle_declaration():
+    qasm = """
+    angle[16] pos = 10;
+    """
+    with pytest.raises(ValueError):
+        Interpreter().run(qasm)
+
+
 def test_constant_declaration():
     qasm = """
     const float[16] const_tau = 2 * π;