[Libguestfs] [Bug 1046905] New: RFE: add argument to virt-sysprep to disable individual default operations

[Richard W.M. Jones]

On Thu, Jan 09, 2014 at 04:21:10PM +0100, Pino Toscano wrote:
> +  and set_operations op_string =
> +    let currentopset =
> +      match (!operations) with

No need for parentheses around !operations.

> +        let n = ref op_name in
> +        let remove = string_prefix op_name "-" in
> +        if remove then
> +          n := String.sub op_name 1 (String.length op_name - 1);
> +        match !n with

This can be written a bit more naturally as ...

  let n, remove =
    if string_prefix op_name "-" then
      String.sub op_name 1 (String.length op_name-1), true
    else
      op_name, false in
  match n with
  ...

> +          let f = if remove then Sysprep_operation.remove_defaults_from_set else Sysprep_operation.add_defaults_to_set in
> +          f opset

You can actually write:

  (if remove then Sysprep_operation.remove_defaults_from_set
   else Sysprep_operation.add_defaults_to_set) opset

I don't know which way you think is clearer, but I would avoid the >80
character lines.

> +    "--operations", Arg.String set_operations, " " ^ s_"Enable/disable specific operations";

I'd also add an alias "--operation" (it would just do the same thing).

> +let add_list_to_opset l s =
> +  List.fold_left (
> +    fun acc elem ->
> +      OperationSet.add elem acc
> +  ) s l
> +
> +let remove_list_from_opset l set =
> +  OperationSet.fold (
> +    fun elem opset ->
> +      if List.exists (
> +        fun li ->
> +          li.name = elem.name
> +      ) l then
> +        opset
> +      else
> +        OperationSet.add elem opset
> +  ) set empty_set

OCaml Set has subset, intersection, difference operations if you need
them.  See /usr/lib64/ocaml/set.mli

Rich.

-- 
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