(*

Module: Dpkg

    Parses /etc/dpkg/dpkg.cfg

Author: Robin Lee Powell <rlpowell@digitalkingdom.org>

About: License

    This file, and the attendant test_dpgk.aug, are explicitly

    placed in the public domain.

About: Description

    dpkg.cfg is a simple list of options, the same ones as the

    command line options, with or without a value.

    The tree is a list of either comments or option/value pairs by

    name. Use "set" to set an option with a value, and "clear" for a

    bare option.

About: Usage Example

(start code)

    $ augtool -n

    augtool> ls /files/etc/dpkg/dpkg.cfg

    #comment[1] = dpkg configuration file

    #comment[2] = This file can contain default options for dpkg.  All command-line

    #comment[3] = options are allowed.  Values can be specified by putting them after

    #comment[4] = the option, separated by whitespace and/or an `=' sign.

    #comment[5] = Do not enable debsig-verify by default; since the distribution is not using

    #comment[6] = embedded signatures, debsig-verify would reject all packages.

    no-debsig = (none)

    #comment[7] = Log status changes and actions to a file.

    log = /var/log/dpkg.log

    augtool> get /files/etc/dpkg/dpkg.cfg/no-debsig

    /files/etc/dpkg/dpkg.cfg/no-debsig (none)

    augtool> get /files/etc/dpkg/dpkg.cfg/log

    /files/etc/dpkg/dpkg.cfg/log = /var/log/dpkg.log

    augtool> clear /files/etc/dpkg/dpkg.cfg/testopt

    augtool> set /files/etc/dpkg/dpkg.cfg/testopt2 test

    augtool> save

    Saved 1 file(s)

    augtool>

    $ cat /etc/dpkg/dpkg.cfg.augnew

    # dpkg configuration file

    #

    # This file can contain default options for dpkg.  All command-line

    # options are allowed.  Values can be specified by putting them after

    # the option, separated by whitespace and/or an `=' sign.

    #

    # Do not enable debsig-verify by default; since the distribution is not using

    # embedded signatures, debsig-verify would reject all packages.

    no-debsig

    # Log status changes and actions to a file.

    log /var/log/dpkg.log

    testopt

    testopt2 test

(end code)

*)

module Dpkg =

  autoload xfm

  let sep_tab = Util.del_ws_tab

  let sep_spc = Util.del_ws_spc

  let eol = del /[ \t]*\n/ "\n"

  let comment = Util.comment

  let empty   = Util.empty

  let word = /[^,# \n\t]+/

  let keyword = /[^,# \n\t\/]+/

  (* View: record

      Keyword, followed by optional whitespace and value, followed

      by EOL.

      The actual file specification doesn't require EOL, but the

      likelihood of the file not having one is pretty slim, and

      this way things we add have EOL.

  *)

  let record = [ key keyword . (sep_spc . store word)? . eol ]

  (* View: lns

      Any number of empty lines, comments, and records.

  *)

  let lns = ( empty | comment | record ) *

  let xfm = transform lns (incl "/etc/dpkg/dpkg.cfg")