doc/langref: document the terms package and module

[perillo]

The language reference uses the terms package and module, but they are not documented.

The module term is used two times and the package term is used five times.

I also think that the use of package and module in https://ziglang.org/documentation/master/#Top-Level-Doc-Comments is confusing.

Thanks.

[batiati]

I think that officially it is called container by Zig.

[perillo]

@batiati: from the compiler source code I found the terms:

1. compilation:

   Should be result of a compilation, like an executable or library.

2. module:

   Compilation of all Zig source code is represented by one Module.
   Each Compilation has exactly one or zero Module, depending on whether
   there is or is not any zig source code, respectively.

3. package:

   Should a collection of source code that has a name that can be used by @import.

4. namespace:

   The container that structs, enums, unions, and opaques have.

5. container:

   XXX

6. file:

   XXX

[perillo]

Some of these terms are used when describing the scope.

As an example in https://ziglang.org/documentation/master/#setFloatMode:

The floating point mode is inherited by child scopes, and can be overridden in any scope. You can set the floating point mode in a struct or module scope by using a comptime block.

By the way, IMHO struct should be replaced by container.

[batiati]

Yeah, my bad.

For example, this build.zig file:

const lib = b.addStaticLibrary("mylib", "src/lib.zig");

• mylib is a package, and can be imported with @import("mylib")
• all source code referenced by "src/lib.zig" is a module
• the binary resultant is a compilation (executable or library)

In the specific case of Top-Level Doc Comments §, I think it's correct to say that //! are applied for the package.

[perillo]

Reading the std code I noted that the term module is used incorrectly in some files:

• debug.zig:

  /// Inside a test block, it is best to use the `std.testing` module rather

• enums.zig:

  ///! This module contains utilities and data structures for working with enums.

• x.zig:

  inline for (.{ os, net }) |module| {