Can you change an input pin in a .COMP?

I am writing a simple component that has a GUI screen variable as an input
In a perfect world, I also wanted to change the value using an analog value in GcodeSo, I would like the screen variable updated if a value is set by a gcode M68 command to keep everything in step like this

I get a compiler lvalue required error. So I am assuming that means input pins are read only and cannot be modifed within a component.

Is this the case and is there any workaround.?

andypugh wrote:

You can use an internal value that is set by the higher (or lower) of either of the two inputs.
Or maybe have a handler in the GUI that allows the GUI value to be over-written by an M-code.

Andy, thanks, I think the GUI approach would be best. Gmocappy uses glade and I have edited the plasma.glade XML file in the sim by hand.to tidy up a couple of things but I don't really know where to start to add a new GUI handler that overwrites the target voltage. I guess that would get done in plasma.py.

Can you give me an idea on where to start?

Would the first step be to add a screen variable for the M68 value and set the target voltage in the python file to that value?

Sorry for responding years later but yes, there is a way,

each input pin you define is just a macro, so first just undefine temporarily, for example:

POS_CMD is an input from simple_tp.comp. I just added feedback to that component so when simple_tp is disabled i want pos_cmd=pos_fb, so what you must do is push the macro in the preprocessor stack, undefine the input pin macro, modify it as dereference access (like if you where in a "normal" c component) and then pop from the stack

#pragma push_macro("remove_pos_cmd")
#undef pos_cmd
*(__comp_inst->pos_cmd) = curr_pos;
#pragma pop_macro("remove_pos_cmd")

best regards
Franco