[augeas-devel] [PATCH] php lens

[Bryan Kearney]

David Lutterkort wrote:
> On Tue, 2008-04-22 at 17:01 -0400, Bryan Kearney wrote:
>> Attached is a patch to add a php lens. Couple of notes:
>>
>> 1) This is pretty much a copy of yum except for the line
>>
>> let value = /[^\n]*(\n[ \t]+[^ \t\n]+)*/
>>
>> In yum it is
>>
>> let value = /[^ \t][^\n]*(\n[ \t]+[^ \t\n]+)*/
>>
>> This was becuase the default php.ini has many blank items
>> foo=
>>
>> where the yum pattern added a newline.
> 
> The yum pattern is fairly complicated because yum allows 'continuation
> lines', as in
> 
>         baseurl=http://server1/path
>           http://server2/path
>         
> i.e., you can split one logical value across multiple lines (I want to
> fix that so that you get multiple baseurl entries in the tree instead of
> one with a string you need to split yourself).
> 
> It seems that php.ini is a little simpler and that values simply extend
> to the end of the line, so that
>    let value = /[^\n]*/
> should work 

It can have trailing comments, so I will play with it a bit.
> 
>> 2) I can not get the test to work. If I run augtest, it fails. If I run 
>> augtest ini-php.change.rb I get the following
>>
>> [bkearney at localhost tests]$ augtest ini-php-change.rb
>> ./../lenses/php.aug:13.2-.50:Failed to compile kv
>> syntax.c:1846 Fixme: Cleanup loaded modules
>> Failed to initialize Augeas
>> Test ini-php-change ... FAIL
>> Expected file ./../build/augtest/etc/php.ini.augnew
>>
>>
>> If I run it manually, it works. Any help on how to solve the testing, I 
>> will go change it.
> 
> Are you sure ? For me, augparse refuses to load the file:
> 
>         galia:[10138] augeas>augparse -I lenses/ lenses/php.aug 
>         lenses/php.aug:13.2-.50:Failed to compile kv
>         lenses/php.aug:13.13-.42:exception: ambiguous concatenation
>               'A: ' can be split into
>               'A:|=| '
>         
>              and
>               'A: |=|'
>         
>             First lens: lenses/php.aug:13.13-.28
>             Second lens: lenses/php.aug:13.31-.42
>         
>         lenses/php.aug: error: Loading failed
>         
> When developing new lenses/schema, it is best to write a lenses/foo.aug
> side by side with unit tests in lenses/tests/test_foo.aug (using Augeas'
> builtin testing, not augtest) and running
> 
>         augparse -I lenses lenses/tests/test_foo.aug
>         
> augparse will give you much better error messages than augtool (and does
> more checking, by default, since some checks are pretty expensive).
> Writing those tests[1] makes it easier to 'bootstrap' lenses, since you
> can start with tests on very simple data (or test lenses other than the
> 'main' lens) and see exactly the tree that Augeas generates.

ok.. good to know. I did augtool and it worked fine.
> 
> The error above complains that the concatenation of 'key key_re .
> eq' (the first lens, the "13.13-.28" means "line 13 from columns 13 to
> 28') and 'store value' (the second lens) is ambiguous and gives you an
> example: a line like "A: " can either be parsed in two ways:
>      1. as "A:" matching the first lens and " " matching the second lens
>         (the '|=|' is a separator Augeas uses to indicate positions in
>         strings)
>      2. as "A: " matching the first lens and "" matching the second lens
> IOW, it doesn't know whether to take a space after a colon and treat is
> as part of the 'eq', in which case it is omitted from the tree, or match
> it as part of the 'store value', in which case the space shows up in the
> tree.
> 
> Augeas is a bit of a stickler for such details, but as this example
> shows, that is necessary to make sure the right action is taken on
> matches.
> 
> If I change value to /(()|[^ \t\n][^\n]*)/, augparse at least is happy.
> I couldn't run your test since I don't have your php.ini to run it
> against ;) That regexp says 'a value is either the empty word[2], or a
> nonspace character followed by any number of non-newline characters[3]'
> 
> David
> 
> [1] http://augeas.net/docs/writing-schemas.html
> [2] You need to use '()' in a regexp for the empty string, because of a 
>     bug in my regexp parser (in fa.c) - POSIX allows stuff like '(|a)' 
>     to match the empty string or an 'a', but my regexp parser gets 
>     confused and sees that as "a literal '|' followed by an 'a'" - something
>     I need to fix; in the meantime, you have to write '(()|a)' in such
>     constructs.
> [3] In yet another deviation from POSIX, you can write /[^\n]/ as /./, i.e.,
>     the dot does not match newlines; that one is intentional and I actually
>     think of it as a feature ;) You can therefore write the new regexp for 
>     value above as /(()|[^ \t\n].*)/
> 
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