One thing I just can't understand is proactively using the :: syntax. It's sooo ugly with so much unnecessary line noise. Just use a single period! I think one of the best decisions D made was to get of -> and :: and just use . for everything.
One thing I just can't understand is proactively using the :: syntax. It's sooo ugly with so much unnecessary line noise. Just use a single period! I think one of the best decisions D made was to get of -> and :: and just use . for everything.
I like to quickly at a glance be able to distinguish between "this is a member access on an object" and "this is referencing something in a module".
I like that the compiler can distinguish those two things too, so that I can refer to things within modules even if I happen to also have a local variable with the same name. Go sometimes annoys me because I need to rename a module or a variable just because the syntax doesn't distinguish between the two things.
> distinguish between "this is a member access on an object" and "this is referencing something in a module".
zig: what's the difference?
There is an overlap between module and class namespacing through static members and functions. Zig sees this and says "let's only have the latter" (on structs), which means among other things that in Zig a file is a structure. Most other languages says "let's have both".
In C3 it goes the other way despite having methods, and says "let's not allow static variables or methods".
This also goes hand in hand in the language approaches between open/close. Zig is very strongly "closed" and C3 is very much "open" (adding methods to types anywhere, appending to modules anywhere etc)
It's an interesting contrast that leads to very different code layouts.
Surely Zig differentiates between, say, a function in a module, and a member on an object? Or are "modules" literally just instances of classes or something?
all structs are namespaces (there no classes). namespaces may contain declarations (consts and functions) or fields ("fields" are slightly different for unions or certain builtins like arrays and slices)
unions and enums also create namespaces. any @import creates a namespace that is a struct.
If a function's first argument is the type of the function's namespace or a pointer to the type of the namespace, you may (and by convention are encouraged to) use dot dereferencing (like python firso parameter self) as a lexical sugar to call the function with the "implicitly rearranged" first parameter ("oop style caling, but not really oop")
modules are somewhat different, in zig these are collections of code you can map to a non-filepath import string using the command line or build tool (in particular you may map something out of code root path), but these too ultimately become a namespace struct
No, they are the same.
`::` simplifies the module vs identifier resolution.
In C3 there is something called "path shortening", allowing you to use `foo::bar()` in place of something like `std::baz::foo::bar()`. To do something similar with `.` is problematic, because you don't know where the path ends. Is `foo.baz.bar()` referring to `foo::baz::bar()` or `foo::baz.bar()` or `foo.baz.bar()`?
I would just explicit require pulling `foo` into scope, like Rust does. Though in fairness Rust also uses :: for scope anyway and I don't think it's as bad as sfpotter says.
Sure, but in practice I believe most developers would find it intuitive to just type . everywhere.
It feels more lightweight and consistent, and collisions aren’t super common once you adopt some conventions.
It’s a tradeoff for sure, but this preference comes from having lived in both worlds.
> Sure, but in practice I believe most developers would find it intuitive to just type . everywhere.
Yeah, but in practice I try not to produce write-only code.
Code is for reading more than for writing, hence make it easier to read. If it becomes easier to write as a side-effect, then so be it.
I’ve lived in both and I prefer ::.
I prefer a world where there is no distinction between modules (or namespaces) and object, so '.' it is. (and I'm almost exclusively a C++ programmer).
N=1; I find :: a lot more obvious.
This is the kind of thing I don't want to have to think about as a programmer. The compiler should just make it work.
But you have to. Ambiguities hint at lack of redundancies that also affects code reading. When you quickly scan something like `file.open` vs `file::open` the former is also more unclear to a reader without more context.
> `::` simplifies the module vs identifier resolution
The identifier on the right is looked up in the scope of the identifier on the left. If it resolves to a module, then it's a module. If it resolves to a function, then it's a function. If the left side is a pointer (not a symbol with a scope) then the right side resolves to a member.
It also makes refactoring much easier - changing a pointer to a reference does not require a global search/replace of -> with .
C3 has "path shortening", so for example given `open(...)` in std::io::file is usually used as `file::open(...)`. If we would to write this as `file.open(...)`. Consider now the case of mistyping `open`: `file.openn(...)`. Is this (A) mistyping the function open in module `std::io::file` or is it (B) the global/local `file` is missing from the current scope?
Also, "io", "file", "random" etc are commonly used variables, so the issue with shadowing is real.
`File file = file::open(...)` is completely unambiguous and fine. `File file = file.open(...)` on the other hand would be bad.
If the language had flat modules, or no path shortening, then it would be possible.
> Is this (A) mistyping the function open in module `std::io::file` or is it (B) the global/local `file` is missing from the current scope?
D uses a spell checker for undefined identifiers, and the dictionary is all the identifiers in scope. It has about a 50% success rate in guessing which identifier was meant, which is quite good.
> Also, "io", "file", "random" etc are commonly used variables, so the issue with shadowing is real.
If the same identifier is accessible through multiple lookup paths, an error is issued. If a local variable shadows a variable in an outer scope, and error is issued.
We've developed this over several years, and it works quite well.
Path shortening can be done with:
or:If I would have liked, I could have done something like `import std::io::file as file;` but I noticed that we keep getting this issue that we’re renaming things all of the time, and usually in the same way. This is why path shortening is there. To directly get something like the informal `file_open` namespacing in C programs.
Standardisation of code and examples across codebases is a nice result of this too. This makes the code easier to learn and share
I feel like path shortening is the issue, and IMO it's an unnecessary feature. I don't think most programmers are bothered by the need to explicitly import what they use. I'd personally prefer to explicitly import what I use, and refer to it in whatever way the import statement would imply.
In Rust where modules share a namespace with other identifiers, I just pick different variable names, or write my imports so they don't conflict. It's not that big a deal.
If anything, my default way of working in Rust is not to type out imports by hand; I just type what I want, then let rust-analyzer prompt me with what options there are to import it from and select the one I mean, and the import gets added to the to of the file. Occasionally I'll need to edit the imports myself for some reason (like if I have a dependency that's enabled only on platforms other than the one I'm developing on), but for the most part I just don't really think about it at all. I totally agree with you that I'd be way less happy with using wildcard imports, and I often to out of my way to avoid aliasing imports by using the full path in the case of ambiguity because I personally find it easier to read something like `std::io:: Result` than `IoResult` (with a corresponding `use std::io::Result as IoResult;` when I want to have a different `Result` in scope. I don't think it's a problem that being able to alias imports like that is an option, but I just happen not to find it particularly appealing even compared to using full paths.
What works for Rust works for Rust. My intent is to make code feel similar to C namespacing. What works and what doesn’t is fairly contextual, depending other language semantics as well.
I can understand it, I just hate it. I would prefer confusing dots, a module builtin namespace, rebol backslashes, confusing slashes, anything else.
I can live with "this::that", but what drives me bonkers is "this :: that", which is what Odin does. Other than that, Odin is an incredible language.
that's a constant assignment, completely different. And you're not going to see it 100s of times in a project.
I concur RE: «::». For deep levels of nesting, the level of noise that «::» causes becomes excessive.
When Rust was in its infancy, I maintained a local fork for a while where I modified the parser to use the Ada syntax («'», a single apostrophe) for the same purpose. So
became But I am not convinced that using «.» for two distinct purposes – 1) as a name qualifier, and 2) as a method/data element accessor – is a good idea, for maintaining the semantic clarity is important, i.e. is «e» in «a.b.c.d.e» It is not easy to say whilst just glancing upon the code.I like it. It disambiguates when you're referring to a member of an object -- myobj.member vs referring to a global object by its full name -- module::function. I guess you could say the IDE can colour the two differently, but after spending a lot of time working with various code review tools of varying quality, I have come to really appreciate having the program text be as explicit as possible. If you find it so disagreeable, can't you configure your IDE to visually replace that syntax with a single dot and also automatically convert a single dot to two colons when typing a namespace?