Re: [Caml-list] format strings

[Jiten Pathy <jpathy@fssrv.net>]

Ok, If i am not supposed to use make_printf, then what is the
recommended way of writing the following?

This adds a new line to given format string. In particular how do i
manipulate the format strings passed to me?


open CamlinternalFormat;;
let f (Format (fmt, _)) =
  make_printf (fun o acc -> output_acc o (Acc_char_literal (acc,
'\n')); ignore o) stdout End_of_acc fmt
;;
val f : ('a, out_channel, unit, unit, unit, unit) format6 -> 'a = <fun>

utop # f "%s %d" "# " 3;;
#  3
- : unit = ()

I now have a slightly better understanding of CamlinternalFormat.



On Mon, Feb 9, 2015 at 11:44 PM, David Allsopp <dra-news@metastack.com> wrote:
> Jiten Pathy wrote:
>> nvm. make_printf is what I am after.
>
> No it isn't - using internal functions is, to 1 significant figure, never what you're after. Apart from anything, you're instantly forcing your code to be 4.02+
>
>> Some complicated stuff is going on in CamlInternalFormat.
>
> Indeed - 4.02 has a very clever reimplementation of the printf engine.
>
>> On Mon, Feb 9, 2015 at 5:05 PM wrote:
>> > Is there a way I can define a function which has the same signature of
>> > printf family but is a no-op?
>> >
>> > f : ('a, 'b, unit) format -> 'a
>
> Printf.ifprintf (you can do similar with Printf.ksprintf and Printf.ikfprintf).
>
> I don't know what lead you to read CamlInternalFormat.mli, but the reference manual (http://caml.inria.fr/pub/docs/manual-ocaml-4.02/libref/Printf.html) is a much better place to start for information on these modules than their source code.
>
>
> David