Add convenience method Circuit.add_clexpr_from_logicexp() (#1681)

pytket/binders/circuit/Circuit/add_op.cpp

@@ -513,6 +513,35 @@ void init_circuit_add_op(py::class_<Circuit, std::shared_ptr<Circuit>> &c) {
           ":param args: The bits to apply the expression to\n"
           ":return: the new :py:class:`Circuit`",
           py::arg("expr"), py::arg("args"))
+      .def(
+          "add_clexpr_from_logicexp",
+          [](Circuit *circ, const py::tket_custom::LogicExpression &exp,
+             const py::tket_custom::SequenceVec<Bit> &output_bits,
+             const py::kwargs &kwargs) {
+            py::list outputs;
+            for (const auto &bit : output_bits) {
+              outputs.append(bit);
+            }
+            py::module clexpr = py::module::import("pytket.circuit.clexpr");
+            py::object add_op =
+                clexpr.attr("_add_clexpr_to_circuit_from_logicexp");
+            add_op(circ, exp, outputs, **kwargs);
+            return circ;
+          },
+          "Append a :py:class:`ClExprOp` defined in terms of a logical "
+          "expression.\n\n"
+          "Example:\n"
+          ">>> c = Circuit()\n"
+          ">>> x_reg = c.add_c_register('x', 3)\n"
+          ">>> y_reg = c.add_c_register('y', 3)\n"
+          ">>> z_reg = c.add_c_register('z', 3)\n"
+          ">>> c.add_clexpr_from_logicexp(x_reg | y_reg, z_reg.to_list())\n"
+          ">>> [ClExpr x[0], x[1], x[2], y[0], y[1], y[2], z[0], z[1], z[2]; "
+          "]\n\n"
+          ":param exp: logical expression\n"
+          ":param output_bits: list of bits in output\n"
+          ":return: the updated circuit",
+          py::arg("exp"), py::arg("output_bits"))
       .def(
           "add_custom_gate",
           [](Circuit *circ, const composite_def_ptr_t &definition,

pytket/docs/changelog.rst

@@ -20,6 +20,7 @@ Features:
 * Use `ClExprOp` by default when converting from QASM.
 * Extend `DecomposeClassicalExp` to handle `ClExprOp` as well as
   `ClassicalExpBox`.
+* Add convenience method `Circuit.add_clecpr_from_logicexp()`.
 
 Deprecations:
 

pytket/pytket/_tket/circuit.pyi

@@ -1461,6 +1461,22 @@ class Circuit:
         :param args: The bits to apply the expression to
         :return: the new :py:class:`Circuit`
         """
+    def add_clexpr_from_logicexp(self, exp: pytket.circuit.logic_exp.LogicExp, output_bits: typing.Sequence[pytket._tket.unit_id.Bit], **kwargs: Any) -> Circuit:
+        """
+        Append a :py:class:`ClExprOp` defined in terms of a logical expression.
+        
+        Example:
+        >>> c = Circuit()
+        >>> x_reg = c.add_c_register('x', 3)
+        >>> y_reg = c.add_c_register('y', 3)
+        >>> z_reg = c.add_c_register('z', 3)
+        >>> c.add_clexpr_from_logicexp(x_reg | y_reg, z_reg.to_list())
+        >>> [ClExpr x[0], x[1], x[2], y[0], y[1], y[2], z[0], z[1], z[2]; ]
+        
+        :param exp: logical expression
+        :param output_bits: list of bits in output
+        :return: the updated circuit
+        """
     @typing.overload
     def add_conditional_barrier(self, barrier_qubits: typing.Sequence[int], barrier_bits: typing.Sequence[int], condition_bits: typing.Sequence[int], value: int, data: str = '') -> Circuit:
         """

pytket/pytket/circuit/clexpr.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 
 from dataclasses import dataclass
+from typing import Any
 
 from pytket.circuit import (
     Bit,
@@ -194,3 +195,10 @@ def check_register_alignments(circ: Circuit) -> bool:
             ):
                 return False
     return True
+
+
+def _add_clexpr_to_circuit_from_logicexp(
+    circ: Circuit, exp: LogicExp, output_bits: list[Bit], **kwargs: Any
+) -> None:
+    wexpr, args = wired_clexpr_from_logic_exp(exp, output_bits)
+    circ.add_clexpr(wexpr, args, **kwargs)

pytket/tests/clexpr_test.py

@@ -235,3 +235,23 @@ def test_circbox() -> None:
     c2 = c1.copy()
     c2.flatten_registers()
     assert c1 == c2
+
+
+def test_add_logicexp_as_clexpr() -> None:
+    c = Circuit()
+    a_reg = c.add_c_register("a", 3)
+    b_reg = c.add_c_register("b", 3)
+    c_reg = c.add_c_register("c", 3)
+    c.add_clexpr_from_logicexp(a_reg | b_reg, c_reg.to_list())
+    qasm = circuit_to_qasm_str(c, header="hqslib1")
+    assert (
+        qasm
+        == """OPENQASM 2.0;
+include "hqslib1.inc";
+
+creg a[3];
+creg b[3];
+creg c[3];
+c = (a | b);
+"""
+    )