Error when using `import`.

[Steven Schveighoffer]

On Monday, 26 February 2024 at 22:40:49 UTC, Liam McGillivray 
wrote:
> On Sunday, 25 February 2024 at 03:23:03 UTC, Paul Backus wrote:
>> You can't give a class the same name as the file it's in. If 
>> you do, then when you try to use it from another file, the 
>> compiler will get confused and think you're referring to the 
>> file instead of the class (that's what "import is used as a 
>> type" means).
>
> Thank you. In PHP, I was told to put every class definition in 
> a file of the same name (whether I like it or not).
>
> However, I actually now have it working *without* having done 
> that. Both the file name and the class name are capitalized, 
> and it's working. However, maybe that's because they each start 
> with a `module` line that makes the module name lowercase. I 
> will keep this in mind, and maybe rename the files.

So D is weird about this. I always recommend you use a *package* 
(i.e. module foo.bar) instead of just a module (i.e. module bar).

When you omit the module declaration, the compiler assumes the 
module name is the same as the file name *without the path taken 
into account*.

What happens is if you have `Map` as a module, and then `Map` as 
the class name, using the name `Map` is going to be confusing 
(did you mean the module or the class?)

However, if you have everything under a package, for example 
`foo`, i.e. a file `foo/Map.d` which contains the `Map` class, 
then when referring to `Map`, it can't be referring to the 
module, since you would have to refer to `foo.Map` for that. This 
means the class name `Map` by itself is unambiguous.

A whole host of problems occurs with name lookup when you don't 
use packages.

-Steve