Date: Tue, 03 Mar 2015 04:32:05 +0300 From: Andrey Chernov <ache@freebsd.org> To: Allan Jude <allanjude@freebsd.org>, freebsd-current@freebsd.org Subject: Re: Massive libxo-zation that breaks everything Message-ID: <54F50F15.4050300@freebsd.org> In-Reply-To: <54F504EF.3030303@freebsd.org> References: <54F31510.7050607@hot.ee> <54F34B6E.2040809@astrodoggroup.com> <CAG=rPVfcB1Fy_8mHq-t5Ay07yrzuSGthQ0ZcGzvp0XG9gSSzkg@mail.gmail.com> <54F35F29.4000603@astrodoggroup.com> <54F429EF.5050400@freebsd.org> <54F46536.8040607@mu.org> <54F4C03F.7030704@freebsd.org> <54F4FECB.90501@freebsd.org> <54F504EF.3030303@freebsd.org>
next in thread | previous in thread | raw e-mail | index | archive | help
This is an OpenPGP/MIME signed message (RFC 4880 and 3156)
--x7vPIp1MaM7fxIJd0xniGlIruAErHh1qO
Content-Type: text/plain; charset=koi8-r
Content-Transfer-Encoding: quoted-printable
On 03.03.2015 3:48, Allan Jude wrote:
> On 2015-03-02 19:22, Andrey Chernov wrote:
>> On 02.03.2015 22:55, Julian Elischer wrote:
>>> On 3/2/15 5:27 AM, Alfred Perlstein wrote:
>>>>
>>>>
>>>> On 3/2/15 4:14 AM, Julian Elischer wrote:
>>>>> On 3/1/15 10:49 AM, Harrison Grundy wrote:
>>>>>> Thanks!
>>>>>>
>>>>>> That does seem useful, but I'm not sure I see the reasoning behind=
>>>>>> putting into base, over a port or package, since processing XML in=
base
>>>>>> is a pain, and it can't serve up JSON or HTML without additional
>>>>>> utilities anyway.
>>>>>>
>>>>>> (If I'm reviving a long-settled thing, let me know and I'll drop i=
t.
>>>>>> I'm
>>>>>> trying to understand the use case for this.)
>>>>>
>>>>> To me it would almost seem more useful to have a programmable filte=
r
>>>>> for which you could produce
>>>>> parse grammars to parse the output of various programs..
>>>>> thus
>>>>>
>>>>> ifconfig -a | xmlize -g ifconfig | your-favourite-xml-parser
>>>>> with a set of grammars in /usr/share/xmlize/
>>>>> then we could use it for out-of-tree programs as well if we wrote
>>>>> grammars for them..
>>>>>
>>>>> The sentiment of machine-readable output is nice, but I think it's
>>>>> slightly off target.
>>>>> we shouldn't have to change all out utilities, and it isn't going t=
o
>>>>> help at all with 3rd party apps,
>>>>> e.g. samba stuff. A generally easy to program output grammar parser=
>>>>> would be truely useful.
>>>>> and not just for FreeBSD.
>>>>>
>>>>> I've been watching with an uncomfortable feeling, but it's taken me=
a
>>>>> while to put my
>>>>> finger on what it was..
>>>>>
>>>>>
>>>> Are you sure it's not the hairs on the back of your neck standing up=
>>>> due to NIH?
>>>>
>>>> Juniper has been doing this for years and it's very useful for them.=
>>> I'm not saying the ability to generate machine readable output is wro=
ng,
>>> but that the 'unix way' would be to make a filter for it. It seems th=
at
>>> the noisy people don't
>>> agree with me so I will not stand in the way of progress..
>>
>> I agree. Even if someone starts with json and xml only, it will need
>> some 3rd format soon, and adding any new format have real possibility =
to
>> break all already existent (like adding json+xml breaks plain text in
>> pipes). Moreover, it violates Unix principle 'one tool =3D=3D one gene=
ral
>> function' and lots of other rules like Eric Raymond ones, making each
>> program looks like systemd. It makes harder to merge changes from othe=
r
>> BSDs too.
>> Proper way to do this thing is to back out all changes and write
>> completely separate templates-based parser - xml/json writer.
>>
>=20
> Have you actually looked at libxo? It isn't really specific to xmj/json=
,
> and could handle adding another format without the need to modify wc
>=20
> xo_open_container("wc");
> xo_open_list("file");
> xo_open_instance("file");
> if (cnt(*argv) !=3D 0)
> ++errors;
> xo_close_instance("file");
> xo_close_list("file");
> xo_close_container("wc");
> xo_finish();
>=20
>=20
> with cnt() being the existing functions in wc, but with the printf
> replaced with an xo wrapper. There is nothing specific to json or xml,
> that is all handled in libxo.
So, why you ever need to modify wc? Just load wc inside your
json/xml/etc writer, replacing its printf at the ld-elf.so level.
If you can't get json/xml/whatever from wc directly, it is not wc
problem, so don't touch it. The problem is on your side, feel free to
implement anything you need without affecting source code of others.
> Obviously, more care needs to be taken when converting the utilities to=
> ensure that the existing output is not changed, but it is not quite as
> invasive as some people seem to think.
I think yes, it is very invasive and leads to dead end as architectural
design.
--=20
http://ache.vniz.net/
--x7vPIp1MaM7fxIJd0xniGlIruAErHh1qO
Content-Type: application/pgp-signature; name="signature.asc"
Content-Description: OpenPGP digital signature
Content-Disposition: attachment; filename="signature.asc"
-----BEGIN PGP SIGNATURE-----
iQEcBAEBCAAGBQJU9Q8fAAoJEKUckv0MjfbK5ioH/0Ds1EvyHevGoLq6KIhZHhcS
CwicLW445TzI5IkvPXtSmxzVv0vjT6ArDluDfB2mDTFTY7ktqfS73Tk1IhpGDSht
4g4Q6QZwXg3s6DudyH98UCJdZLg2u/vfpniwdYXqhJqbDdRvoktGqixx9uzJUk/k
GxE6QwJu4sJFesm1y5PrEYo2hkCPUw2RDpElefwh4pgavlu0xgRDdcZA3sNafgsn
NwJYC9YDTwhp5/Q9FDiDYL/I6W7GiHG/LMLOkVQ0EuhvInRrNXxeSwHCkhZCy1c0
GMRRCCGr//y+XAQN1fgkjoxoCXeRdcXFF9eAZbB3wLQIfP5Dof/RbxeY4GDT7Fo=
=1MiE
-----END PGP SIGNATURE-----
--x7vPIp1MaM7fxIJd0xniGlIruAErHh1qO--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?54F50F15.4050300>