[augeas-devel] Wildcarded key/value pairs and nested blocks (dovecot lens development)

[Raphaël Pinson]

Great! We'd surely welcome a Pull Request. In that case, could you adjust
the license to use LGPLv2+ as the rest of Augeas, and use NaturalDocs
documentation in comments (see keepalived.aug for example)?



On Thu, Mar 7, 2013 at 7:06 PM, Serge Smetana <serge.smetana at gmail.com>wrote:

> Hi Raphaël,
>
> Thank you very much. I finally understood Build.block* and recursive
> lenses.
> Please find the final lens here
>
> https://github.com/smetana/augeas/blob/00f125a39e2fc9512df8deb779650673a4da4609/lenses/dovecot.aug
>
> If you like it I can make pull request to augeas repository.
>
> Thank you,
> Serge
>
> On Thu, Mar 7, 2013 at 6:00 PM, Raphaël Pinson
> <raphael.pinson at camptocamp.com> wrote:
> >
> >
> > On Thu, Mar 7, 2013 at 4:33 PM, Serge Smetana <serge.smetana at gmail.com>
> > wrote:
> >>
> >> Hi Raphaël,
> >>
> >> Trying to use Build.block_newlines construct
> >>
> >>    let any = Rx.no_spaces
> >>    let value = any . (Rx.space . any)*
> >>    let commands  = /include|include_try/
> >>    let block_names =
> >> /dict|userdb|passdb|protocol|service|plugin|namespace|map/
> >>    let nested_block_names =
> >> /fields|unix_listener|fifo_listener|inet_listener/
> >>    let keys = Rx.word - commands - block_names - nested_block_names
> >
> >
> > This kind of constructs makes augparse (and run) verrrrrrrrrrrrry
> slooooow.
> > It is best to rewrite them as:
> >
> >    let keys = Rx.word - (commands | block_names | nested_block_names)
> >
> > which is strictly equivalent, but much faster.
> >
> >
> >>
> >>
> >>    let entry = [ indent . key keys. eq . (Sep.opt_space . store value)?
> .
> >> eol ]
> >>    let command = [ command_start . key commands . Sep.space . store
> >> Rx.fspath . eol ]
> >>
> >>    let block_args   = Sep.space . store any
> >>
> >>    let nested_block = [ indent . key block_names . block_args? .
> >> Build.block_newlines entry comment . eol ]
> >>    let block = [ indent . key block_names . block_args? .
> >> Build.block_newlines (entry|nested_block)* comment . eol]
> >>
> >>    let lns = (comment|empty|entry|command|block)*
> >>
> >> If I try to compile this I get an exception: ambiguous concatenation
> >>
> >>       First regexp: /([
> >> \t]*)(dict|userdb|passdb|protocol|service|plugin|namespace|map)((([
> >> \t]+)([^ \t\n]+))?)/
> >>       Second regexp: /([ \t\n]+\\{([ \t\n]*\n)?)((((([
> >> \t]*)((dict[.0-9A-Z_a-z-][.0-9A-Z_a-z-]| ...... <long regexp
> >> here>.....
> >>
> >>       'userdb {# {\n}' can be split into
> >>       'userdb|=| {# {\n}'
> >>
> >>      and
> >>       'userdb {#|=| {\n}'
> >>
> >>
> >> I guess this is because of optional block_args? in lens definition.
> >
> >
> >
> > Yes, precisely. Spaces must belong only to one side of two concatenated
> > expressions.
> >
> >
> >>
> >> But my old variant without Build.block* construct works:
> >>
> >>   let block_open        = del /[ \t]*\{/ "{"
> >>   let block_close       = del /\}/ "}"
> >>
> >>   .... same as above
> >>
> >>   let nested_block =
> >>        [ indent . key nested_block_names . block_args? . block_open .
> eol
> >>        . (entry | empty | comment)*
> >>        . indent . block_close . eol ]
> >>
> >>    let block =
> >>        [ indent . key block_names . block_args? . block_open . eol
> >>        . (entry | empty | comment | nested_block )*
> >>       . indent . block_close . eol ]
> >
> >
> >
> > Build.block_newlines allows things like
> >
> >     unix_listener {# {\n}
> >
> > where "# {\n" should be a comment.
> >
> > However, block_args? allows *any* character (including "#" and "{") to be
> > present between the key and the opening bracket. I think block_args
> should
> > be refined to only allow the characters you need.
> >
> >
> > Regards,
> >
> > --
> > Raphaël Pinson
> > Administrateur Systèmes & Réseaux
> > Camptocamp France
> > Savoie Technolac
> > BP 352
> > 48, avenue du Lac du Bourget
> > 73372 Le Bourget du Lac, Cedex
> > www.camptocamp.com
>



-- 
Raphaël Pinson
Administrateur Systèmes & Réseaux
Camptocamp France
Savoie Technolac
BP 352
48, avenue du Lac du Bourget
73372 Le Bourget du Lac, Cedex
www.camptocamp.com
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