Resolve "Operation Replacement in a SFG"

Added method with tests for replacing multiple operations in a sfg with another operation with the same amount of input / output ports. Closes #17

b_asic/signal_flow_graph.py

@@ -405,6 +405,37 @@ class SFG(AbstractOperation):
         # The old SFG will be deleted by Python GC
         return self()
 
+    def replace_operations(self, operation_ids: Sequence[GraphID], operation: Operation):
+        """Replace multiple operations in the sfg with a operation with the same amount of inputs and outputs.
+        Then return a new deepcopy of the sfg with the replaced operations.
+
+        Arguments:
+        operation_ids: The id's of the operations we are replacing
+        operation: The operation used for replacement.
+        """
+
+        _sfg = self()
+
+        input_signals = []
+        output_signals = []
+
+        for _operation in [_sfg.find_by_id(_id) for _id in operation_ids]:
+            input_signals.extend(filter(lambda s: s.source.operation.graph_id not in operation_ids, _operation.input_signals))
+            output_signals.extend(filter(lambda s: s.destination.operation.graph_id not in operation_ids, _operation.output_signals))
+
+        assert len(input_signals) == operation.input_count, "The input count must match"
+        assert len(output_signals) == operation.output_count, "The output count must match"
+
+        for index_in, _signal in enumerate(input_signals):
+                _signal.remove_destination()
+                _signal.set_destination(operation.input(index_in))
+
+        for index_out, _signal in enumerate(output_signals):
+                _signal.remove_source()
+                _signal.set_source(operation.output(index_out))
+      
+        return _sfg()
+
     def _evaluate_source(self, src: OutputPort, results: MutableResultMap, registers: MutableRegisterMap, prefix: str) -> Number:
         src_prefix = prefix
         if src_prefix:

[Angus Lothian]

What this method does is replace a set of operations with an entered operation, which is good and probably what Oscar wants to do most of the time. However in the Requirements Specification the requirement is that a set of operations should be able to be replace with another set of operations.

Not sure if this is completely necessary though, but otherwise we have to change the requirements specification. What do you think @ivaha717 ?