Re: [gentoo-dev] [PATCH] eapi7-ver.eclass: 'Early adopter' version of EAPI 7 version manip

[Michał Górny]

W dniu nie, 10.09.2017 o godzinie 03∶05 +1200, użytkownik Kent Fredric
napisał:
> On Fri,  8 Sep 2017 13:19:23 +0200
> Michał Górny <mgorny@g.o> wrote:
>
> > a. getting wider review and some real-life testing before
> > the specification is set in stone, and
>
> Any thoughts on a function that would represent a dotted-decimal style version
> as a floating point string?
>
> eg:
>
>   ver_float 0.1.0    -> 0.001
>   ver_float 0.10.0   -> 0.010
>   ver_float 0.100.0  -> 0.100
>
> That's of course *the most* generic example I can offer, but seeing
> this sort of transformation is commonly needed in the world of perl, I
> thought maybe now is a good time to mention something.
>
> Sadly, its just the sort of idea that if done wrong, would be no use.
>
> For instance, sometimes you want:
>
>    ver_float 0.1.0  -> 0.0010
>
> Or
>
>    ver_float 0.1.1  -> 0.001001
>
> The two key things here is to know:
>
> 1. How many digits each position represents
> 2. The maximum number of digits to represent
>
> So, some ideas in that regard are:
>
>    ver_float ${INPUT} ${PRECISION}
>
> Where the values per position are fixed, so:
>
>     ver_float 0.1 3   -> 0.001
>     ver_float 0.1 2   -> INVALD  # fidelity loss by truncation
>     ver_float 0.10 2  -> 0.01    # permitted because there's no fidelity loss by truncation
>     ver_float 0.100 1 -> 0.1     # permitted because there's no fidelity loss by truncation
>     ver_float 0.100 2 -> 0.10
>     ver_float 0.100 3 -> 0.100
>     ver_float 0.101 1 -> INVALID # fidelity loss by truncation
>
>     ver_float 0.1 5   -> 0.00100
>     ver_float 0.1.1 5 -> INVALID, need 6 digits to represent 0.1.1
>
>     ver_float 0.1.1 6 -> 0.001001
>
>
> Or say,
>
>     ver_float ${INPUT} ${PATTERN}
>
> Where "pattern" is a string like 3-3-3 indicating how to map digits to numbers
>
>      ver_float 0.1      3    -> 0.001
>      ver_float 0.1      2    -> 0.01
>      ver_float 0.1      1    -> 0.1
>      ver_float 0.1.1    3    -> # INVALID, no map for '.1'
>      ver_float 0.1.1    3-3  -> 0.001001
>      ver_float 0.1.10   3-3  -> 0.001010
>      ver_float 0.1.10   2-2  -> 0.0110
>      ver_float 0.10.10  2-2  -> 0.1010
>      ver_float 0.100.10 2-2  -> # INVALID, can't map "100" into 2 characters
>
> Though I suspect you'd want both features ...
>
>      ver_float ${INPUT} ${PATTERN} ${TRUNCATION_LENGTH}
>
> Because we do need packages where
>
>      0.123.10 means 0.1231
>
> Either way, much of this is probably a time wasting bad idea.
>
> But I thought I'd just
>
> ( •_•)
>
> ( •_•)>⌐■-■
>
> (⌐■_■)
>
> Float it by you.
>

I'm not sure if there's a serious proposal behind all this but I suppose
it's all just perl-specific insanity that is of no value to everyone
else.

-- 
Best regards,
Michał Górny