(*

Module: Erlang

  Parses Erlang configuration files

Author: Raphael Pinson <raphael.pinson@camptocamp.com>

About: Reference

  This lens tries to keep as close as possible to `http://www.erlang.org/doc/man/config.html` where possible.

About: License

   This file is licenced under the LGPL v2+, like the rest of Augeas.

About: Lens Usage

   To be documented

About: Configuration files

   This lens applies to Erlang configuration files. See <filter>.

About: Examples

   The <Test_Erlang> file contains various examples and tests.

*)

module Erlang =

(* Group: Spacing Functions *)

(* View: space *)

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

(* View: lspace

     Add spaces to the left of char *)

let lspace (char:string) = del (/[ \t\n]*/ . char) char

(* View: rspace

     Add spaces to the right of char *)

let rspace (char:string) = del (char . /[ \t\n]*/ ) char

(* View: lrspace

     Add spaces to the left or right of char *)

let lrspace (char:string) = del (/[ \t\n]*/ . char . /[ \t\n]*/ ) char

(* Group: Separators *)

(* Variable: lbrace

     Left square bracket *)

let lbrace = "{"

(* Variable: rbrace

     Right square bracket *)

let rbrace = "}"

(* Variable: lbrack

     Left curly brackets *)

let lbrack = "["

(* Variable: rbrack

     Right curly brackets *)

let rbrack = "]"

(* Variable: lglob

     Left glob separator *)

let lglob = "<<\""

(* Variable: rglob

     Right glob separator *)

let rglob = "\">>"

(* Variable: comma *)

let comma = ","

(* Group: Value types *)

(* View: opt_list

     An optional list of elements, in square brackets *)

let opt_list (lns:lens) = rspace lbrack

                        . (Build.opt_list lns (lrspace comma) . space)?

                        . Util.del_str rbrack

(* View: integer

     Store a <Rx.integer> *)

let integer = store Rx.integer

(* View: decimal

     Store a decimal value *)

let decimal = store /[0-9]+(.[0-9]+)?/

(* View: quoted

     Store a quoted value *)

let quoted = Quote.do_quote (store /[^,\n}{]+/)

(* View: bare

     Store a bare <Rx.word> *)

let bare = store Rx.word

(* View: boolean

     Store a boolean value *)

let boolean = store /true|false/

(* View: path

     Store a path (<quoted>) *)

let path = quoted

(* View: glob

     Store a glob *)

let glob = Util.del_str lglob . store /[^\n"]+/ . Util.del_str rglob

(* View: make_value

     Make a "value" subnode for arrays/tuples *)

let make_value (lns:lens) = [ label "value" . lns ]

(* Group: Store types *)

(* View: value

     A single value *)

let value (kw:regexp) (sto:lens) =

  [ rspace lbrace

  . key kw

  . lrspace comma

  . sto

  . lspace rbrace ]

(* View: tuple

     A tuple of values *)

let tuple (one:lens) (two:lens) =

  [ rspace lbrace

  . label "tuple"

  . [ label "value" . one ]

  . lrspace comma

  . [ label "value" . two ]

  . lspace rbrace ]

(* View: tuple3

     A tuple of 3 values *)

let tuple3 (one:lens) (two:lens) (three:lens) =

  [ rspace lbrace

  . label "tuple"

  . [ label "value" . one ]

  . lrspace comma

  . [ label "value" . two ]

  . lrspace comma

  . [ label "value" . three ]

  . lspace rbrace ]

(* View: list

     A list of lenses *)

let list (kw:regexp) (lns:lens) =

  [ rspace lbrace

  . key kw

  . lrspace comma

  . opt_list lns

  . lspace rbrace ]

(* View: value_list

     A <list> of seq entries *)

let value_list (kw:regexp) (sto:lens) =

  list kw (make_value sto)

(* View: application *)

let application (name:regexp) (parameter:lens) =

  list name parameter

(* View: kernel_parameters

     Config parameters accepted for kernel app *)

let kernel_parameters =

    value "browser_cmd" path

  | value "dist_auto_connect" (store /never|once/)

  | value "error_logger" (store /tty|false|silent/)

  | value "net_setuptime" integer

  | value "net_ticktime" integer

  | value "shutdown_timeout" integer

  | value "sync_nodes_timeout" integer

  | value "start_dist_ac" boolean

  | value "start_boot_server" boolean

  | value "start_disk_log" boolean

  | value "start_pg2" boolean

  | value "start_timer" boolean

(* View: kernel

     Core Erlang kernel app configuration *)

let kernel = application "kernel" kernel_parameters

(* View: comment *)

let comment = Util.comment_generic /%[ \t]*/ "% "

(* View: config

     A top-level config *)

let config (app:lens) =

    (Util.empty | comment)*

  . rspace lbrack

  . Build.opt_list (kernel | app) (lrspace comma)

  . lrspace rbrack

  . Util.del_str "." . Util.eol

  . (Util.empty | comment)*