From e1e1730e8ab41cd6bcfc655b1a78993442797d7b Mon Sep 17 00:00:00 2001
From: Roland Siegbert <roland.siegbert@phys.ethz.ch>
Date: Sat, 14 Sep 2024 15:04:56 +0200
Subject: [PATCH 1/2] Add `reset` to QasmParser

Add a test which can serve as example including the modifications to
support the `reset` keyword in the import of QASM files in the PLY based
lexer/parser.
---
 cirq-core/cirq/contrib/qasm_import/_lexer.py  |  5 ++++
 cirq-core/cirq/contrib/qasm_import/_parser.py | 11 +++++++
 .../cirq/contrib/qasm_import/_parser_test.py  | 30 +++++++++++++++++++
 3 files changed, 46 insertions(+)

diff --git a/cirq-core/cirq/contrib/qasm_import/_lexer.py b/cirq-core/cirq/contrib/qasm_import/_lexer.py
index 206d9e88d74..d13ebf349f7 100644
--- a/cirq-core/cirq/contrib/qasm_import/_lexer.py
+++ b/cirq-core/cirq/contrib/qasm_import/_lexer.py
@@ -29,6 +29,7 @@ def __init__(self):
     reserved = {
         'qreg': 'QREG',
         'creg': 'CREG',
+        'reset': 'RESET',
         'measure': 'MEASURE',
         'if': 'IF',
         '->': 'ARROW',
@@ -95,6 +96,10 @@ def t_MEASURE(self, t):
         r"""measure"""
         return t
 
+    def t_RESET(self, t):
+        r"""reset"""
+        return t
+
     def t_IF(self, t):
         r"""if"""
         return t
diff --git a/cirq-core/cirq/contrib/qasm_import/_parser.py b/cirq-core/cirq/contrib/qasm_import/_parser.py
index e7bcdae06db..1d9e8606047 100644
--- a/cirq-core/cirq/contrib/qasm_import/_parser.py
+++ b/cirq-core/cirq/contrib/qasm_import/_parser.py
@@ -293,6 +293,7 @@ def p_format(self, p):
     # circuit : new_reg circuit
     #         | gate_op circuit
     #         | measurement circuit
+    #         | reset
     #         | if circuit
     #         | empty
 
@@ -303,6 +304,7 @@ def p_circuit_reg(self, p):
     def p_circuit_gate_or_measurement_or_if(self, p):
         """circuit :  circuit gate_op
         |  circuit measurement
+        |  circuit reset
         |  circuit if"""
         self.circuit.append(p[2])
         p[0] = self.circuit
@@ -499,6 +501,15 @@ def p_measurement(self, p):
             ops.MeasurementGate(num_qubits=1, key=creg[i]).on(qreg[i]) for i in range(len(qreg))
         ]
 
+    # reset operations
+    # reset : RESET qarg
+
+    def p_reset(self, p):
+        """reset : RESET qarg ';'"""
+        qreg = p[2]
+
+        p[0] = [ops.ResetChannel().on(qreg[i]) for i in range(len(qreg))]
+
     # if operations
     # if : IF '(' carg EQ NATURAL_NUMBER ')' ID qargs
 
diff --git a/cirq-core/cirq/contrib/qasm_import/_parser_test.py b/cirq-core/cirq/contrib/qasm_import/_parser_test.py
index 4b0ca8e50f1..23c31bdf928 100644
--- a/cirq-core/cirq/contrib/qasm_import/_parser_test.py
+++ b/cirq-core/cirq/contrib/qasm_import/_parser_test.py
@@ -706,6 +706,36 @@ def test_measurement_bounds():
         parser.parse(qasm)
 
 
+def test_reset():
+    qasm ="""
+     OPENQASM 2.0;
+     include "qelib1.inc";
+     qreg q[1];
+     creg c[1];
+     x q[0];
+     reset q[0];
+     measure q[0] -> c[0];
+     """
+
+    parser = QasmParser()
+
+    q_0 = cirq.NamedQubit('q_0')
+
+    expected_circuit = Circuit()
+    expected_circuit.append(cirq.X(q_0))
+    expected_circuit.append(cirq.ResetChannel().on(q_0))
+    expected_circuit.append(cirq.MeasurementGate(num_qubits=1, key='c_0').on(q_0))
+
+    parsed_qasm = parser.parse(qasm)
+
+    assert parsed_qasm.supportedFormat
+    assert parsed_qasm.qelib1Include
+
+    ct.assert_same_circuits(parsed_qasm.circuit, expected_circuit)
+    assert parsed_qasm.qregs == {'q': 1}
+    assert parsed_qasm.cregs == {'c': 1}
+
+
 def test_u1_gate():
     qasm = """
      OPENQASM 2.0;

From 9d2be2daf0dcd9ebfd6674dcf66a03fa554f290c Mon Sep 17 00:00:00 2001
From: Roland Siegbert <roland.siegbert@phys.ethz.ch>
Date: Sat, 14 Sep 2024 15:09:22 +0200
Subject: [PATCH 2/2] Fix comments & typos

---
 cirq-core/cirq/contrib/qasm_import/_parser.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/cirq-core/cirq/contrib/qasm_import/_parser.py b/cirq-core/cirq/contrib/qasm_import/_parser.py
index 1d9e8606047..f2b30423c2d 100644
--- a/cirq-core/cirq/contrib/qasm_import/_parser.py
+++ b/cirq-core/cirq/contrib/qasm_import/_parser.py
@@ -293,7 +293,7 @@ def p_format(self, p):
     # circuit : new_reg circuit
     #         | gate_op circuit
     #         | measurement circuit
-    #         | reset
+    #         | reset circuit
     #         | if circuit
     #         | empty
 
@@ -505,7 +505,7 @@ def p_measurement(self, p):
     # reset : RESET qarg
 
     def p_reset(self, p):
-        """reset : RESET qarg ';'"""
+        """reset : RESET qreg ';'"""
         qreg = p[2]
 
         p[0] = [ops.ResetChannel().on(qreg[i]) for i in range(len(qreg))]