Re: [Caml-list] global record

[Richard Jones <rich@annexia.org>]

On Wed, Jul 19, 2006 at 01:11:22PM +0200, Andreas Biegert wrote:
> I am developing a bioinformatics sequence analysis application which
> contains about 20 modules. One of those modules, the 'Par' module,
> encapsulates a record of about 30 configuration parameters needed
> throughout the whole application. The parameter record is mostly
> static but some values can be overwritten by command-line options. Is
> there a way to make the (possibly modified) parameters record globally
> accessable throughout all modules? This would be much more convenient
> than having to pass the parameters record to virtually all functions
> in my application. THX for helping.

This is a bit ugly, but we use it in our Adwords API toolkit:

-------------------------------------------------- stdargs.mli
val username : string
val password : string
val client : string option
val token : string
val update : bool
val verbose : bool
val args : string list

-------------------------------------------------- stdargs.ml
let username = ref ""
let password = ref ""
let client = ref ""
let token = ref ""
let update = ref false
let verbose = ref false
let args = ref []

(* followed by some code which tries to read default values
 * from $HOME/.adwordsapidata -- code omitted
 *)

(* parse the command line parameters *)
let argspec = [
  "--username", Arg.Set_string username, "Adwords account username.";
  "--password", Arg.Set_string password, "Adwords account password.";
  "--client", Arg.Set_string client, "Adwords account client (optional).";
  "--token", Arg.Set_string token, "Adwords account token.";
  "--update", Arg.Set update, "Perform updates.";
  "--verbose", Arg.Set verbose, "Be verbose.";
]

let anon_fn str = args := str :: !args
let usage =
  Sys.executable_name ^ " [--options]"

let () = Arg.parse argspec anon_fn usage

let username = !username
let password = !password
let client = if !client = "" then None else Some !client
let token = !token
let update = !update
let verbose = !verbose
let args = List.rev !args

---

Then the code just stuff like:

  open Stdargs

  if verbose then printf "this is verbose mode\n"

Rich.

-- 
Richard Jones, CTO Merjis Ltd.
Merjis - web marketing and technology - http://merjis.com
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