4. If autodim is enabled, then goto dimmer
GOTO?

For the one-liners, they're great way to save yourself from a lot of scrolling, I'm writing code in that way for last 40 years, so I don't think that now is the time to change.
OK but I thought we've showed by now that PBP is not "the same" as interpreted BASIC on you ZX Spectrum from '82.If you're sure that your one-liners work then fine but you wanted suggestion on how to debug the code and I was trying to give you ideas on what to try but never mind.