Re: [gentoo-user] emerge sets syntax (@world vs. world)

[Francesco Turco <fturco@fastmail.fm>]

On Wed, Dec 12, 2012, at 14:18, Alan McKinnon wrote:
> You are wrong, the docs and the man pages are correct.
> 
> The problem is that the word "set" is used in two different ways, one
> loosely and the other with reference to an exact construct.
> 
> portage-2.2 introduced the concept of "a defined set" under user
> control. It's a list of packages that portage treats as a whole chunk
> of things together and the user can define what he wants in a set and
> give it a name. When used with emerge, sets like this must have an "@"
> prefix so portage can tell them apart from regular packages. Portage
> also dynamically creates sets internally that work the same way, things
> like @world and @system and @preserved-rebuild. You can use these too,
> you just can't define them or modify them directly.
> 
> The portage man page has unfortunately also used the word "set" for a
> different reason. Portage has always had a concept of "world" (not
> @world) and "system" (not @system) which were really "just a bunch of
> stuff that happens to pop out of portage because it's hard-coded that
> way". And the docs say things like 
> 
> emerge world
> 
> and call the "world" part "the world set".
> 
> "Set" here is a homonym - two completely different words with different
> meanings that just happen to be spelled and sound the same.

I'm still not convinced. emerge(1) man page for portage-2.1.11.37
already contains the following command example:
> emerge --update --newuse --deep @world

And:
> emerge  --update  @world

But not a single example without the at sign.

I also found this (old) blog post from Portage developer Zac Medico:
http://blogs.gentoo.org/zmedico/2010/09/07/portage_2-1-9_release/. It
says:
> Package set names in emerge arguments have to be prefixed with @ (exceptions: ‘world’ and ‘system’ can be used without the prefix).

So it seems that since version 2.1.9 @world and world (and @system and
system) are just treated in the same way, but prefixing them with the at
symbol is more future-proof.