Massive libxo-zation that breaks everything

Andrey Chernov ache at
Tue Mar 3 01:37:56 UTC 2015

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 it.
>>>>>> I'm
>>>>>> trying to understand the use case for this.)
>>>>> To me it would almost seem more useful to have a programmable filter
>>>>> 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 to
>>>>> 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 wrong,
>>> but that the 'unix way' would be to make a filter for it. It seems that
>>> 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 == one general
>> function' and lots of other rules like Eric Raymond ones, making each
>> program looks like systemd. It makes harder to merge changes from other
>> BSDs too.
>> Proper way to do this thing is to back out all changes and write
>> completely separate templates-based parser - xml/json writer.
> 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
> xo_open_container("wc");
> xo_open_list("file");
>   xo_open_instance("file");
>     if (cnt(*argv) != 0)
>       ++errors;
>   xo_close_instance("file");
> xo_close_list("file");
> xo_close_container("wc");
> xo_finish();
> 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 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


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