4 ms·

But the Julia syntax can not represent arguments that can be passed either positional or named, right?

• ddragon 7y ago
  Yes it can't, unless of course you just make two variables (one positional and one named) and inside the function you choose one. Because of Julia's multiple dispatch paradigm, positional arguments are special compared to named arguments because they decide what method to dispatch to (in Julia f(x) is equivalent to x.f() in object oriented language, and it's extended to all positional arguments). That means that if you called f(a, b=nothing, c=nothing), f(1, c=1) it would dispatch to f(Int64, Nothing, Int64), while if you called f(a; b=nothing, c=nothing) with the same args it would dispatch to f(Int64). In Julia named arguments are effectively a way to pass more arguments without complicating the dispatch rules, and since there is only one way to call a function (outside of optional arguments, which appears to the end user as another implementation of a function) there is no ambiguity to where it dispatches to. So basically, every language has it's own quirks, which the syntax decisions usually reflects, and Julia's scenario is fundamentally different from Python's.
• chubot 7y ago
  Yeah that's true, but I consider it a feature and not a bug. There was a rule in Google's style guide that said to only pass optional arguments with names, and required args without names. It basically enforced this separation while being slightly less flexible, because you can't have optional positional args or required named args. Tens of millions of lines of code was written by thousands of programmers in that style, and it caused no problems at all. On the contrary it made code more consistent and readable.