Add Support of Chained Method/Function Calls

blark/iec.lark

@@ -722,6 +722,7 @@ _statement: ";"
           | reset_statement
           | reference_assignment_statement
           | return_statement
+          | chained_function_call_statement
           | function_call_statement
           | if_statement
           | case_statement
@@ -752,6 +753,8 @@ return_statement.1: "RETURN"i ";"*
 
 function_call_statement: function_call ";"+
 
+chained_function_call_statement: function_call ("." function_call)+ ";"+
+
 param_assignment: [ LOGICAL_NOT ] variable_name "=>" [ expression ] -> output_parameter_assignment
                 | variable_name ":=" [ expression ]
                 | expression

blark/tests/source/object_oriented_dotaccess.st

@@ -0,0 +1,19 @@
+(* This program uses some object-oriented function-block with multiline access. *)
+PROGRAM oop_test
+VAR
+        uut : SomeFunctionBlock;
+END_VAR
+
+// Use an object that has a different method called on each line
+uut.DoSomething(input_1:='foo', input_2:='bar')
+   .DoSomethingElse(input_1:=5)
+   .Finish();
+
+// Or perhaps something that's a little more tame
+uut.DoSomething(input_1:='foo', input_2:='bar')
+   .DoSomethingElse(input_1:=5).Finish();
+
+// Or something tamer, still
+uut.DoSomething(input_1:='foo', input_2:='bar').DoSomethingElse(input_1:=5).Finish();
+
+END_PROGRAM

blark/tests/test_transformer.py

@@ -1073,6 +1073,11 @@ def test_action_roundtrip(rule_name, value):
             END_FOR
             """
         )),
+        param("chained_function_call_statement", tf.multiline_code_block(
+            """
+            uut.call1().call2().call3.call4().done();
+            """
+        )),
     ],
 )
 def test_statement_roundtrip(rule_name, value):

blark/transform.py

@@ -2604,6 +2604,23 @@ def __str__(self):
         return f"{invoc};"
 
 
+@dataclass
+@_rule_handler("chained_function_call_statement", comments=True)
+class ChainedFunctionCallStatement(Statement):
+    invocations: List[FunctionCall]
+    meta: Optional[Meta] = meta_field()
+
+    @staticmethod
+    def from_lark(*invocations: FunctionCall) -> ChainedFunctionCallStatement:
+        return ChainedFunctionCallStatement(
+            invocations=list(invocations)
+        )
+
+    def __str__(self) -> str:
+        invoc = ".".join(str(invocation) for invocation in self.invocations)
+        return f"{invoc};"
+
+
 @dataclass
 @_rule_handler("else_if_clause", comments=True)
 class ElseIfClause: