Allowing piping for numeric entity states

[Mulando]

State values of entities can now be merged together by piping the entity names. Only works with numbers. If the state is not a number, the first will be used. If another property than "state" is used, only the values of the first entity will be used.

E.g. my inverter does not provide a single sensor for the current grid consumption. Instead each phase has its own value. So I made a small modification to your project by allowing piping sensor entities.

Example:
grid:
entity: >-
sensor.foxessrs485_grid_ct_r | sensor.foxessrs485_grid_ct_s |
sensor.foxessrs485_grid_ct_t

[flixlix]

Thank you for your PR!
I do recognize this is a hack and would like to implement this with the UI editor preferably, but for now I'll merge this :)

[doopa75]

E.g. my inverter does not provide a single sensor for the current grid consumption. Instead each phase has its own value. So I made a small modification to your project by allowing piping sensor entities.
Example: grid: entity: >- sensor.foxessrs485_grid_ct_r | sensor.foxessrs485_grid_ct_s | sensor.foxessrs485_grid_ct_t

I have a sdm630 meter that monitors power on each phase. How do I configure the grid to correctly show power flow?
I have sensors:
solar:
entity: sensor.stp4_0_3av_40_936_grid_power = 300
grid:
entity: sensor.sdm630_sdm630_powerL1 = -100
sensor.sdm630_sdm630_powerL2 = 0
sensor.sdm630_sdm630_powerL3 = 100

example
solar production 300W / 3 = 100W per phase.

House load 300 W (0 W first phase, 100 W second phase, 200 W third phase)

The flow should look like this:
house load 300 W, from the grid 100 W (100 on phase 3), from the sun 200 W (100 W on phase 2 and 100 W on phase 3)

To sum up the network: phase 1 is (minus) -100 W returns to the grid, phase 2 is 0 W (powered by the sun), phase 3 is 100 W (the second 100 W from the sun)

Is it good to configure the energy flow at the current stage of development?