After many years of gradual improvement Vim now takes a big step with a major release. Besides many small additions the spotlight is on a new incarnation of the Vim script language: Vim9 script. Why Vim9 script:
A new script language, what is that needed for? Vim script has been growing over time, while preserving backwards compatibility. That means bad choices from the past often can’t be changed and compatibility with Vi restricts possible solutions. Execution is quite slow, each line is parsed every time it is executed.
The performance improvements can