Re: [Caml-list] Specify the default hash function for a type

[Ben Millwood <bmillwood@janestreet.com>]

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Polymorphic hash operates without type information, so it's not able to
tell that it's hashing your record type vs. some other type with the same
structure. So I would guess that what you want is not possible.

The Core team is working on a ppx extension analogous to ppx_sexp_conv and
ppx_compare which generates hash functions automatically, and would make
this kind of thing possible, but it's not done yet.

On 13 May 2016 at 15:52, Soegtrop, Michael <michael.soegtrop@intel.com>
wrote:

> Dear Ocaml Users,
>
>
>
> I wonder if there is a way to specify a default hash function for a type,
> which is then used by the automated hash functions e.g. created for records
> containing this type. I have e.g. a record with about 10 fields and I am
> happy with the default hash functions for most fields and for the record,
> but for just one field I would like to use a custom hash function, but I
> don’t want to write a hash function for the record.
>
>
>
> I am currently using the standard library, but if there is a solution with
> Batteries or Core, I would also be interested.
>
>
>
> Best regards,
>
>
>
> Michael
>
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