Don't fall into the trap of thinking the entire world is like what you can see from where you're standing. It's not really "not-invented-here", it's "not-invented-there", where "there" is wherever you're used to being. There aren't many unprecedented ideas in Rust.
Not really, a lot of things are taken from sensible theory (e.g. traits and typeclasses).
Beyond that I can't help but feeling that you're following this (IMO) counterproductive cargo cult that holds that sigils are teh 3v1l and everything should be alphanumeric only. Python was at the forefront of this movement but it's now very popular. IMO it's completely counterproductive, even in Python case. It's form over function. You end up with a language where you have to be careful when you refactor because indentation becomes significant and no way to scope your variables properly. Or a language like JS where somebody genuinely thought that having arcane rules to automatically insert semicolons was a reasonable idea because "ewwww semicolons look ugly". It sure looks good if you want to get them tatooed, but in practice at best it's pointless and at worst it gets in the way.
I'm all for descriptive variable and function names but the core syntax of the language is repeated all over the place all the time and benefits from concision. Having Rust spell out "function" instead of "fn" wouldn't disambiguate anything since you're exposed to it within 5 minutes in the language and you'll be super familiar with it very quickly. Having a shorthand means that it doesn't pollute the code listing and leaves more room for the actually important stuff.
A lot of people like to point out Perl as an example of "sigil soup gone wrong" but I'd argue that it's not even the real problem here, Perl can become an unreadable mess because of all the "magic" it allows, meaning you can write code that seems to do absolutely nothing but actually does a whole lot (with things like the implied variable $_ for instance). If you look at an exhaustive list of Perl operators there are only a handful I'd personally consider questionable (like `x` and maybe `<=>`. Also some of the quoting q{} qq{} and qx{} are really obtuse).
I'll respond to that because there is a concrete benefit. For what it's worth, typescript, go, SML, haskell, and many other languages follow this pattern too.
In C, there's the "clockwise spiral rule"[0] to read a complex c declaration. Let's take an example from that:
void (*signal(int, void (*fp)(int)))(int);
In rust, that would be: fn signal(i: isize, fp: Fn(isize) -> ()) -> Fn(isize) -> ()
In rust, the clockwise spiral rule is more simply the "read left to right" rule, which follows more naturally for most people.For what it's worth, C++ also includes alternate function syntax [1], which matches rust's ordering of return values.
The reason it was added to C++ is because there were actual expressions the old syntax could not unambiguously express. Even to a machine the C-style declaration is more confusing.
With no offence meant, you're sounding a little blub[2]-ish in that complaint.
[0]: http://c-faq.com/decl/spiral.anderson.html
[1]: https://en.wikipedia.org/wiki/C++11#Alternative_function_syn...
What he did was essentially he discovered precedence rules for normal C expressions. That's all. https://news.ycombinator.com/item?id=22451431
And that point is pretty much a straw man, intentionally cherry-picked and obfuscated. The type signature in my signal(3) manpage is given as
typedef void (*sighandler_t)(int);
sighandler_t signal(int signum, sighandler_t handler);
And functions taking and returning function pointers are exceedingly rare. In practice I still find C type syntax the easiest to read (it's so concise, and in fact there is almost no type synax because it's just expressions). The valid argument for me why we should move away from that syntax is tooling - the syntax is hard to parse for machines (but not for humans) because it requires serial reading and complete preprocessing from the start of the file.Actually, the C, C++, Java, C# dynasty being the USA of programming languages seems quite fitting in terms of economics.
It's a joy to write rust code for the most part.