Why there is a package declaration in Go?

Question

Why do we need to put a package declaration in every file in folder to mark the specified .go files as a part of a package?

Instead the directory name itself could be a package name for all files it contains.

So what the ideological point for this decision?

As an example of what @JimB is talking about package `import "google.golang.org/api/oauth2/v2"` imports the `oauth2` package and is used as such: `oauth2.New(...)`. — RayfenWindspear, Apr 04 '17 at 20:21
I understand that it is NOT related. BUT my question was not about the current implementation. It is about the advantages of current implementation versus the old one plain directories. — Egor Shalashnikov, Apr 04 '17 at 21:12
Package main is just as simple as putting your main proc into main folder. — Egor Shalashnikov, Apr 04 '17 at 21:13
Anyway, I've seen the doc from Rob Pike or some related guys with the detailed description of their package ideology , with explanations and examples. If you remeber link to it, it'll be great — Egor Shalashnikov, Apr 04 '17 at 21:15
The use of the package declaration is that you may use a Go _identifier_ as the package name. A folder name may not be a valid Go identifier, and a Go identifier may not be a valid folder name. More on this in this answer: [What is the purpose of the package declaration?](http://stackoverflow.com/questions/38563990/what-is-the-purpose-of-the-package-declaration/38564329#38564329) — icza, Apr 05 '17 at 07:37

score 1 · Accepted Answer · answered Apr 04 '17 at 23:51

Instead the directory name itself could be a package name for all files it contains.

Egor, you probably suppose that in one directory go-files only from one package.

You are almost correct if you exclude tests.

Tests are exception from rule "one directory - one package".

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