Add visitor for ExternPortStatement to parser.

Author: hodgestar

source/openpulse/openpulse/ast.py

@@ -131,6 +131,15 @@ class CalibrationBlock(QASMNode):
     body: List[Statement]
 
 
+@dataclass
+class ExternPortStatement(QASMNode):
+    """
+    Node representing an extern port statement.
+    """
+
+    name: Identifier
+
+
 # Override the class from openqasm3
 @dataclass
 class CalibrationStatement(Statement):

source/openpulse/openpulse/parser.py

@@ -43,6 +43,7 @@
     span,
     QASMNodeVisitor,
     _raise_from_context,
+    _visit_identifier,
     parse as parse_qasm3,
 )
 from openqasm3.visitor import QASMVisitor
@@ -194,6 +195,9 @@ def visitCalibrationBlock(self, ctx: openpulseParser.CalibrationBlockContext):
                 body=[self.visit(statement) for statement in ctx.openpulseStatement()]
             )
 
+    def visitExternPortStatement(self, ctx: openpulseParser.OpenpulseStatementContext):
+        return openpulse_ast.ExternPortStatement(name=_visit_identifier(ctx.Identifier()))
+
     def visitScalarType(self, ctx: openpulseParser.ScalarTypeContext):
         if ctx.WAVEFORM() or ctx.PORT() or ctx.FRAME():
             return self._visitPulseType(ctx)