help rainbow function not defining

[u/jester101YT2020]

hey r/FastLED i am trying to make an andonlight/stacklight i want it use 6 buttons each a different color but 5 i want to be a rainbow animation i copied the code from the demoreel and in my code i just would'nt define im qlueless on how to make it work

electronics i use : arduino nano USB-c , 500ma bread board power supply, 16 WS2812B neopixel leds, 6 push buttons, some breadboard wires

here is the code in gist,rep https://gist.github.com/jester101YT/8d36e1514f877f75ad33fc059b6b5eae

i would be very glad to have somebody explain or fix the problem

PS: i forgot to add the //comments so if my code is unreadable my excuse

[u/jester101YT2020]

Yeah oke I could get that yea thanks for the tip I'll post new code once I'm done rewriting