Passing macro argument to custom mcode

[azs123]

Hi. Im trying to implement filament run-out handler using python dsf. I want to send custom mcode with parameter as shown on the screenshot:
When error occurs on one of the sensors, i want to forward 'D' parameter to dsf. "echo {param.D}" works fine and prints extruder number as expected. However, when trying to catch this mcode in dsf, parameter 'S' is equal to string "{param.D}" instead of actual extruder number:

I wonder if this is a bug, limitation or i'm doing something wrong. Currently using RRF 3.4

[chrishamm]

@azs123 You need to call EvaluateExpression in your custom code handler to get the actual value of that parameter if it is an expression. Afair there is another code parameter property to flag this.