Re: Proposal of a better hash table implementation based on SRFI 125

["Jéssica Milaré" <jessymilare@gmail.com>]

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Finally finished the libraries.

SRFI-125 is implemented. I took the liberty to create a procedure
scm_hash_n_items in 'libguile/hashtab.c' that works with both normal and
weak hash tables, so the GENERIC-HASH-TABLES module don't need to keep
track of the hash table size anymore.

`make check` runs everything ok. I believe it's ready for testing. Any
feedback is welcome.

Regards,
Jéssica

Em sáb, 12 de jan de 2019 às 18:34, Jéssica Milaré <jessymilare@gmail.com>
escreveu:

> (It seems I mistakenly responded only to a personal e-mail, sorry,
> responded now to everyone in the list with updates).
>
> So here are the news:
>
> I've created a module called (ice-9 generic-hash-tables), which is similar
> to SRFI-125, and used it to implement SRFI-69, (RNRS HASHTABLES), SRFI-126
> and SRFI-125. Since SRFI-125 depends on SRFI-128, I've implemented it as
> well. My public repository already has SRFI-128, I'm just finishing some
> tests with SRFI-125 and, once they are done, I'll push it as well.
>
> The module (ice-9 generic-hash-tables), is quite usable and all exported
> procedures are documented. I've created tests for it and also ported
> standard tests from SRFI-126.
>
> Now, I see that 'libguile/hashtab.h' code keeps track of the number of
> elements in hash tables, but the field is not visible from Scheme. Can that
> be changed? Then generic hash tables wouldn't need to also keep track of
> the number of elements (like SRFI-69 currently does) and that would
> simplify its code.
>
> Besides, what about creating new versions HASHX-* procedures that accept
> an equivalence procedure instead of an assoc procedure? Perhaps prefixed by
> 'NEW-' or post-fixed by a '*'.
>
> I've also found inconsistencies between SRFI-125 and it's reference
> implementation and standard tests. I've implemented according to the
> specification - so, for instance, HASH-TABLE=? checks if the equivalence
> function of both hash tables are the same and HASH-TABLE returns an
> immutable hash table.
>
> Code is public and suggestions are always welcome :)
> https://github.com/jessymilare/guile
>
> Regargs,
> Jéssica
>
> Em dom, 30 de dez de 2018 às 15:50, Amirouche Boubekki <
> amirouche@hypermove.net> escreveu:
>
>> Le 2018-12-28 17:11, Jéssica Milaré a écrit :
>> > Hello,
>> >
>> > As I said in a previous e-mail, currently SRFI-69 is broken for weak
>> > hash tables - and I've sent a patch to fix it. However, I think there
>> > are many other problems with current implementation of hash tables.
>> > There are guile standard hash tables, SRFI-69 hash tables (which is
>> > implemented on top of standard hash tables) and also R6RS hash tables
>> > (which is implemented on top or SRFI-69 and completely lacks support
>> > for weak keys and/or values).
>> >
>> > I think that should be fixed and guile should have only two kinds of
>> > hash tables: the standard guile hash table and another extended hash
>> > table type that will be used directly by R6RS, SRFI-125 and SRFI-69.
>> > In my opinion, it should be based on SRFI-125, which is part of R7RS
>> > Red Edition, but also supports some other procedures to make it
>> > compatible with R6RS and SRFI-69, supporting weakness and immutable
>> > hash tables.
>> >
>> > I'm already implementing the SRFI-125 based hash tables library for
>> > myself, so, if that is accepted, I can also make a patch for guile.
>> >
>>
>> Yes please make a patch and attach it to the bug report.
>>
>> Don't forget to send an announcement when you SRFI-125 implementation
>> is ready for testing. Is it already available anywhere?
>>
>> TIA
>>
>

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