Fun fact: Hal Finney (yes, that Hal) wrote a BASIC interpreter for the Intellivision back in 1978 or so in a weekend. It was 2K of code. Mattel shipped it on a cartridge.
ROM space was so tight, the only error message it produced was:
EH?
Which Hal was very proud of. He showed it to me to make me laugh. At the time I was programming the Mattel Intellivision Roulette cartridge.