Re: [Caml-list] Generic printer patch

[Martin Jambon <martin.jambon@ens-lyon.org>]

On 12/08/2011 04:00 AM, Romain Bardou wrote:
>>> 2) Could you imagine to generalize it to Format.formatter or to
>>> out_channel (without creating a string and concatenating)? Romain Bardou
>>> add in the mantis tracker (I can't give you the bugtracking number since
>>> mantis "is currently offline for maintenance") a feature wish for a new
>>> conversion specification that can print anything. Do you think you can
>>> fulfill is dream?
> 
> Here is the feature request I proposed:
> 
> http://caml.inria.fr/mantis/view.php?id=4956
> 
> Here is the response by Pierre Weis:
> 
> "This is a major feature wish that requires careful thinking and a lot
> of work!
> 
> Furthermore, we would not have a completely satisfactory solution in the
> end (due to this <poly> catch all case that tend to propagate, as far as
> you use polymorphic functions). The correct solution to get this feature
> in its full glory is a major modification of the type system along the
> lines of G'Caml.

The feature we want is exactly Jeremie's "hack" (his words). We need
this feature for debugging and displaying data in log files. This kind
of data is almost never polymorphic, so there is no practical issue
here. Also we don't need a standardized output format. However we would
often like to truncate the data to a reasonable size.

I understand that this feature could be replaced in the future by a more
complete solution, but we would be happy if it were provided as an
"experimental extension" of OCaml.


Martin

> In short, a natural feature wish in a strongly typed polymorphic
> language; we had it in mind for decades; unfortunately, we are not yet
> ready to offer it, even in the rather limited extent you proposed."
> 
> In other words: what you did is awesome but I'm not sure that it will be
> added in the trunk :(
> 
> Cheers,
>