[gentoo-user] Portage 2.2

[gentoo-user] Portage 2.2

[Pavel Volkov]

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What is the status or portage 2.2?
It takes so long to get out of alpha. Has anyone here had any serious
problems with it? I've been using it for a a few years without any
accidents. Just wondering if I should be prepared for the worst.
I also remember reading in Changelog that 2.2 remains masked until 2.1 gets
enough testing, that was ages ago.

It initially suported set arithmetic (you could writes expressions like
"@set1+@set2/@set3"), I wonder why it was dropped :)

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Re: [gentoo-user] Portage 2.2

[Alan McKinnon]

On 24/07/2013 12:00, Pavel Volkov wrote:
> What is the status or portage 2.2?
> It takes so long to get out of alpha. Has anyone here had any serious
> problems with it? I've been using it for a a few years without any
> accidents. Just wondering if I should be prepared for the worst.
> I also remember reading in Changelog that 2.2 remains masked until 2.1
> gets enough testing, that was ages ago.
> 
> It initially suported set arithmetic (you could writes expressions like
> "@set1+@set2/@set3"), I wonder why it was dropped :)

you've been using it for years, it has gone through 186 alpha versions
and before that just over 100 pre versions. You never had a problem with
it. Neither has anyone else really.

So what are you worried about again?

Just pretend that "alpha" isn't in the name and it isn't masked -
effectively that is actual status - last I heard from Zac there is one
or two odd edge cases that still aren't 100% right, but few people ever
run into them. You are highly unlikely to be one of those few people.


-- 
Alan McKinnon
alan.mckinnon@gmail.com

Re: [gentoo-user] Portage 2.2

[Yohan Pereira]

On 24/07/13 at 02:00pm, Pavel Volkov wrote:
> It initially suported set arithmetic (you could writes expressions like
> "@set1+@set2/@set3"), I wonder why it was dropped :)

Wow thats intresting. What could the / operator possibly do in the case
of sets?

-- 

- Yohan Pereira

The difference between a Miracle and a Fact is exactly the difference
between a mermaid and a seal.
                -- Mark Twain

Re: [gentoo-user] Portage 2.2

[Neil Bothwick]

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On Wed, 24 Jul 2013 14:00:54 +0400, Pavel Volkov wrote:

> It initially suported set arithmetic (you could writes expressions like
> "@set1+@set2/@set3"), I wonder why it was dropped :)

What does that mean? set1 and one of set2 or set 3? Or both set1 and set2
or set3 only? I'm not sure how this would be useful but I can certainly
see how it would cause confusion and problems, but I hadn't heard if it
before.


-- 
Neil Bothwick

Of course it's not your day,
With 7 billion people on earth chances are slim it will ever be *your* day.

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Re: [gentoo-user] Portage 2.2

[Alan McKinnon]

On 24/07/2013 12:17, Neil Bothwick wrote:
> On Wed, 24 Jul 2013 14:00:54 +0400, Pavel Volkov wrote:
> 
>> It initially suported set arithmetic (you could writes expressions like
>> "@set1+@set2/@set3"), I wonder why it was dropped :)
> 
> What does that mean? set1 and one of set2 or set 3? Or both set1 and set2
> or set3 only? I'm not sure how this would be useful but I can certainly
> see how it would cause confusion and problems, but I hadn't heard if it
> before.
> 
> 

It's standard mathematical set operators. In maths, a set is defined as
"a collection of well-defined objects". Sets have no dupes.

http://en.wikipedia.org/wiki/Set_%28mathematics%29
http://en.wikipedia.org/wiki/Set_theory

Sets have several well-defined operations that can be done on them:
union, intersection, difference plus a few others.

@set1+@set2/@set3 reduces to:

all the elements of set1 and set2 without the elements that are in set3
(/ is difference).

As an example, assume portage ships two sets @kde and @kdedev:

@kde
  kdeadmin-meta
  kdebase-meta
  kdemultimedia-meta
  kdepim-meta
  ...

@kdedev
  kdewebdev-meta
  kdebindings-meta
  kdesdk-meta


However, kmail sucks and akonadi sucks moar, so define for yourself

@suckykde
  kdepim-meta

And add to your world sets:

@kde+@kdedev/@suckykde

effectively giving you kde without kde-pim.
Without operators, you have to copy-paste an existing set and maually
remove the entriess you don't want.

Useful, not so?
Well, it all gets extremely murky very very quickly. Portage applies
more than just mathematical sets, there's this concept of deps that are
not part of set theory.

What if something in set1 has a dep, and that dep is listed in set3 and
must be removed. To resolve this, you must have precedence rules and
must ignore something. You either ignore set3 and install anyway, or
throw a blocker and say the item is required in set1.

Either way there's no clean way to do it and lots of users are going to
get annoyed. Not to mention the extra bug reports





-- 
Alan McKinnon
alan.mckinnon@gmail.com

Re: [gentoo-user] Portage 2.2

[Pavel Volkov]

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On Wed, Jul 24, 2013 at 2:13 PM, Yohan Pereira <yohan.pereira@gmail.com>wrote:

> On 24/07/13 at 02:00pm, Pavel Volkov wrote:
> > It initially suported set arithmetic (you could writes expressions like
> > "@set1+@set2/@set3"), I wonder why it was dropped :)
>
> Wow thats intresting. What could the / operator possibly do in the case
> of sets?
>

I'm not sure about the correct notation but I think it was intersection.

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Re: [gentoo-user] Portage 2.2

[Alan McKinnon]

On 24/07/2013 12:52, Pavel Volkov wrote:
> 
> 
> 
> On Wed, Jul 24, 2013 at 2:13 PM, Yohan Pereira <yohan.pereira@gmail.com
> <mailto:yohan.pereira@gmail.com>> wrote:
> 
>     On 24/07/13 at 02:00pm, Pavel Volkov wrote:
>     > It initially suported set arithmetic (you could writes expressions
>     like
>     > "@set1+@set2/@set3"), I wonder why it was dropped :)
> 
>     Wow thats intresting. What could the / operator possibly do in the case
>     of sets?
> 
> 
> I'm not sure about the correct notation but I think it was intersection.


Difference actually :-)

I can't think how intersection could be generally useful in portage
sets. Maybe it was in the first draft just for completeness?



-- 
Alan McKinnon
alan.mckinnon@gmail.com

[gentoo-user] Re: Portage 2.2

[Nikos Chantziaras]

On 24/07/13 13:00, Pavel Volkov wrote:
> What is the status or portage 2.2?
> It takes so long to get out of alpha. Has anyone here had any serious
> problems with it? I've been using it for a a few years without any
> accidents. Just wondering if I should be prepared for the worst.
> I also remember reading in Changelog that 2.2 remains masked until 2.1
> gets enough testing, that was ages ago.

To me, it looks more like 2.2 is some sort of "eternal testing" version, 
and features from it are added to 2.1 over time.

Now this might not be the intention, but it sure looks that way.

Re: [gentoo-user] Portage 2.2

[Neil Bothwick]

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On Wed, 24 Jul 2013 12:46:59 +0200, Alan McKinnon wrote:

> > What does that mean? set1 and one of set2 or set 3? Or both set1 and
> > set2 or set3 only? I'm not sure how this would be useful but I can
> > certainly see how it would cause confusion and problems, but I hadn't
> > heard if it before.
> > 
> >   
> 
> It's standard mathematical set operators. In maths, a set is defined as
> "a collection of well-defined objects". Sets have no dupes.
> 
> http://en.wikipedia.org/wiki/Set_%28mathematics%29
> http://en.wikipedia.org/wiki/Set_theory
> 
> Sets have several well-defined operations that can be done on them:
> union, intersection, difference plus a few others.
> 
> @set1+@set2/@set3 reduces to:
> 
> all the elements of set1 and set2 without the elements that are in set3
> (/ is difference).
> 
> As an example, assume portage ships two sets @kde and @kdedev:
> 
> @kde
>   kdeadmin-meta
>   kdebase-meta
>   kdemultimedia-meta
>   kdepim-meta
>   ...
> 
> @kdedev
>   kdewebdev-meta
>   kdebindings-meta
>   kdesdk-meta
> 
> 
> However, kmail sucks and akonadi sucks moar, so define for yourself
> 
> @suckykde
>   kdepim-meta
> 
> And add to your world sets:
> 
> @kde+@kdedev/@suckykde
> 

I see, what about operator precedence, is that equivalent to

(@kde+@kdedev)/@kdesuckykde or @kde+(@kdedev/@kdesuckykde)

It's been a long time since I studied set operators at Uni :(


-- 
Neil Bothwick

I cna ytpe 300 wrods pre mniuet!!!

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Re: [gentoo-user] Portage 2.2

[Alan McKinnon]

On 24/07/2013 15:20, Neil Bothwick wrote:
>> However, kmail sucks and akonadi sucks moar, so define for yourself
>> > 
>> > @suckykde
>> >   kdepim-meta
>> > 
>> > And add to your world sets:
>> > 
>> > @kde+@kdedev/@suckykde
>> > 
> I see, what about operator precedence, is that equivalent to
> 
> (@kde+@kdedev)/@kdesuckykde or @kde+(@kdedev/@kdesuckykde)
> 
> It's been a long time since I studied set operators at Uni :(


I think it's the former. But I've been known to be wrong on things
(lately, more often than not...)

Just looked on The Google, and there's no consensus I can find. Best
advice seems to be that union and difference are equal precedence so the
expression is evaluated left to right.

Hence it's the former :-)



-- 
Alan McKinnon
alan.mckinnon@gmail.com

Re: [gentoo-user] Portage 2.2

[Michael Orlitzky]

On 07/24/2013 09:27 AM, Alan McKinnon wrote:
> 
> I think it's the former. But I've been known to be wrong on things
> (lately, more often than not...)
> 
> Just looked on The Google, and there's no consensus I can find. Best
> advice seems to be that union and difference are equal precedence so the
> expression is evaluated left to right.
> 
> Hence it's the former :-)

You can rewrite (A \\ B) as (A && !B), giving you one less case to worry
about.

But, some people (most notably, programming languages) assign a higher
priority to intersection (&&) than they do to union (||). Of course,
mathematically, they should probably have the same priority, so many
people do the left-to-right thing.

So in practice, you'd better use parentheses if you want anyone to know
WTF you're talking about.

Re: [gentoo-user] Portage 2.2

[Willie WY Wong]

On Wed, Jul 24, 2013 at 12:46:59PM +0200, Penguin Lover Alan McKinnon squawked:
> @set1+@set2/@set3 reduces to:
> 
> all the elements of set1 and set2 without the elements that are in set3
> (/ is difference).
> 

Speaking as a mathematician (and A. Gottlieb will agree with me), I
would be rather annoyed that they chose (if this is not a misquote 
from the original proposed documentation) to use '/' for set 
difference instead of '\' as it is supposed to be. 

Humph.

W


-- 
Data aequatione quotcunque fluentes quantitae involvente fluxiones invenire 
         et vice versa   ~~~  I. Newton

Re: [gentoo-user] Portage 2.2

[gottlieb]

On Wed, Jul 24 2013, Willie WY Wong wrote:

> Speaking as a mathematician (and A. Gottlieb will agree with me), I
> would be rather annoyed that they chose (if this is not a misquote 
> from the original proposed documentation) to use '/' for set 
> difference instead of '\' as it is supposed to be. 

I was also surprised to see `/'.  A part of me was going to send about
quotient groups (the normal usage of '/') but I managed to refrain
myself.  However, now that willie has opened the door ...

/ is normally used for quotients.  For example, if we take the group Z
of integers under addition and the subgroup 2Z of the even integers,
then Z / 2Z is the quotient that results from taking Z and identifying
all the elements of 2Z.  So in Z / 2Z, all the even integers are zero
and hence all odd integers are equivalent (since they differ by even
integers, which are zero).  Thus the quotient has only 2 elements and is
the familiar group Z2, the integers mod 2.

The above can be generalized.

allan

Re: [gentoo-user] Portage 2.2

[Alan McKinnon]

On 24/07/2013 22:15, gottlieb@nyu.edu wrote:
> On Wed, Jul 24 2013, Willie WY Wong wrote:
> 
>> Speaking as a mathematician (and A. Gottlieb will agree with me), I
>> would be rather annoyed that they chose (if this is not a misquote 
>> from the original proposed documentation) to use '/' for set 
>> difference instead of '\' as it is supposed to be. 
> 
> I was also surprised to see `/'.  A part of me was going to send about
> quotient groups (the normal usage of '/') but I managed to refrain
> myself.  However, now that willie has opened the door ...
> 
> / is normally used for quotients.  For example, if we take the group Z
> of integers under addition and the subgroup 2Z of the even integers,
> then Z / 2Z is the quotient that results from taking Z and identifying
> all the elements of 2Z.  So in Z / 2Z, all the even integers are zero
> and hence all odd integers are equivalent (since they differ by even
> integers, which are zero).  Thus the quotient has only 2 elements and is
> the familiar group Z2, the integers mod 2.
> 
> The above can be generalized.
> 
> allan
> 

In portage's defense, the symbol used is not really mathematical
notation, it's an operator used in code, and only in code.

We do this lots:

* is multiplication
^ is exponentiation
% is modulus (sometimes just mod)

and several more, all driven by the lack of appropriate symbols on early
ASCII keyboards (and the majority of current keyboards...)

I would probably have selected "/" as well if I were the implementer,
but that's because I heavily resist using backslash for anything other
than escapes. My brain usually will not let me go against this one...

You mathematician chaps could probably resolve this one nicely for
yourselves by treating it as just another mangle by Applied
Mathematicians      <====== joke   :-)


-- 
Alan McKinnon
alan.mckinnon@gmail.com

Re: [gentoo-user] Portage 2.2

[gottlieb]

On Wed, Jul 24 2013, Alan McKinnon wrote:

> You mathematician chaps could probably resolve this one nicely for
> yourselves by treating it as just another mangle by Applied
> Mathematicians      <====== joke   :-)

Careful what you joke about.  The New York University comp sci dept (my
home) is part the Courant Institute that also contains the very highly
regarded NYU math department, one that *emphasizes* applied math. :-)

allan

Re: [gentoo-user] Portage 2.2

[Alan McKinnon]

On 24/07/2013 23:21, gottlieb@nyu.edu wrote:
> On Wed, Jul 24 2013, Alan McKinnon wrote:
> 
>> You mathematician chaps could probably resolve this one nicely for
>> yourselves by treating it as just another mangle by Applied
>> Mathematicians      <====== joke   :-)
> 
> Careful what you joke about.  The New York University comp sci dept (my
> home) is part the Courant Institute that also contains the very highly
> regarded NYU math department, one that *emphasizes* applied math. :-)
> 
> allan
> 


Oops :-)

If I told you my closest colleague at work (who designs the algorithms
for most of the code I maintain) has a masters in pure Mathematics -
would we then at least be even?



-- 
Alan McKinnon
alan.mckinnon@gmail.com