Function Arguments Are Not Function Colors

Under this framework, Rust's async fns would not be colored, since any function in the callstack could be blocking on an executor. if you consider "spawn point" a part of the callstack, many other languages are similar.

This doesn't feel like a useful distinction, but i don't think "function coloring" in general is a useful framework.

I think this is a fine distinction to make, though it's worth noting that function arguments _can be_ colors as the author describes if the arguments have to come from a specific place, e.g. in languages where only `main` receives certain arguments relating to system functionality, or a capability framework where only the top-level function receives the capability token.

Generally when talking about colored functions, I think of an example like "async function" in javascript, those are definitely different colored.

I don't know about what would constitute as colored function in go as I generally don't consider arguments to be function colors.

Maybe methods in go would be different colored functions when they are defined on different struct types.

A subset of function arguments are function colors because async/await is isomorphic to requiring and passing a `callback` arg around. It was named 'callback hell` because there wasn't an escape hatch and it affected every function in the callstack.

I'd venture to guess that there's a more abstract way of formalizing this in the sense that monad instances are required to be threaded through the callstack in particular cases(would love to see this spelled out formally) where IO and Cont(?) have this requirement but State like the author points out, does not.

"Function colors" are just effect systems, which are not a new concept while also being extremely useful and super nifty. I hope someday we can stop wringing our hands in a panic over "colored functions" just because some ancient version of Javascript had a frustrating implementation of one specific effect. It reminds me of how ages ago certain people acquired an instinctual aversion to static typing attributable entirely to ancient versions of Java and its attendant verbosity and relative anemia.