It would be neat if compile-time constants from using the “constant” node were in fact constant data, i.e. stored in the program memory space of the Harvard architecture uPs like the 8 bit Arduino Uno. A quick hack that should work is since a double/Number and a pointer are the same size on the AVR/Microchip 8 bit, one should be able to cast a pointer to program memory space to a Number and pass a reference to the constant data around that way as normal. It would require custom nodes for the storage and any nodes that wished to dereference and use the data, however.
I’m trying to think if there’s a way to do this generally with perhaps just a custom “PROGMEM” node and an intermediary conversion node, via the stack, without having to rewrite every node which accepts a Number or String to be PROGMEM-aware and know how to dereference PROGMEM pointers.