It's the walrus operator. Pascal and Python use it as well. You get used to it pretty quickly.
Pascal: https://www.freepascal.org/docs-html/ref/refse104.html#x224-... Python: https://docs.python.org/3/whatsnew/3.8.html#assignment-expre...
It was something introduced like a 1 april joke. Clean implementation of any programming language won't have that.
I actually think it’s more readable because it makes the distinction between assignment and equivalence very clear.
bugs originating from the similarity of == vs = has probably cost the industry millions over the last 3 decades.
That ship has long sailed. ALGOL 1958 used := and Pascal popularized it.
https://en.m.wikipedia.org/wiki/Assignment_(computer_science...
I think they scan the code by two characters because one is not enough for <= and => so what is why assignment is := or =:. Probably + is ++ too.