code comment on using_explicit_control_flow

src/gt4py/next/program_processors/runners/dace/gtir_scan_translator.py

@@ -312,6 +312,9 @@ def _lower_lambda_to_nested_sdfg(
     # the lambda expression, i.e. body of the scan, will be created inside a nested SDFG.
     nsdfg = dace.SDFG(sdfg_builder.unique_nsdfg_name(sdfg, "scan"))
     nsdfg.debuginfo = gtir_sdfg_utils.debug_info(lambda_node, default=sdfg.debuginfo)
+    # We set `using_explicit_control_flow=True` because the vertical scan is lowered to a `LoopRegion`.
+    # This property is used by pattern matching in SDFG transformation framework
+    # to skip those transformations that do not yet support control flow blocks.
     nsdfg.using_explicit_control_flow = True
     lambda_translator = sdfg_builder.setup_nested_context(lambda_node, nsdfg, lambda_symbols)