Daniel Serpell (dmsc) is the creator of FastBasic, a modern
implementation of the BASIC programming language for the Atari
8-bit computers. He released the first version to the public in
2017. Today, the GPL-licensed language is up to version 4.6, and is
a favorite of 10-line BASIC game contest entrants and anyone who
wants a speedy, modern take on Atari programming.
I'm going to crib from AtariWiki's description of FastBasic:
"It is a complete re-implementation of the BASIC system, using a
built-in bytecode compiler rather than a tokenizing interpreter.
Typical BASICs use an interpreter that examines every line of code
as the program runs. ... FastBasic works on an entirely different
principle. When a line is parsed in FastBasic, it (essentially)
compiles the entire line into tokens and then leaves them in
memory. This way the line does not have to be repeatedly parsed,
even from the simplified token format, which makes it much faster
to run."
FastBasic has other enhancements, including new commands for
player-missiles and communicating with FujiNet, an option to only
use faster integer math instead of floating point, and structured
programming instead of line numbers.