Re: Is there utility in making hash-table-{keys, values} built-in functions?

[Shankar Rao <shankar.rao@gmail.com>]

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This isn't about syntax, as changing hash-table-{keys,values} to be
built-in functions wouldn't change their syntax.

I was curious about this because there doesn't seem to be a way to iterate
over a hash-table without either explicitly or implicitly using a lambda.
For example, if we macro expand the following cl-loop

(cl-loop for key being hash-keys of tables using (hash-values v)
         collect (func k v))

we obtain:

(cl-block nil
  (cl-block --cl-finish--
    (maphash
     (lambda
       (key v)
       (func k v))
     tables))
  nil)

Most languages that provide a hash-table data structure provide methods for
directly accessing the hash keys and values. I'm trying to understand if it
would be beneficial for elisp to provide these as well. Would it provide a
significant enough speed boost for code that frequently iterates over hash
keys/values? Is there some complication implementing these functions in C
directly?

Shankar Rao

On Thu, Nov 28, 2024 at 7:40 PM Gerd Möllmann <gerd.moellmann@gmail.com>
wrote:

> Shankar Rao <shankar.rao@gmail.com> writes:
>
> > Hello all,
> >
> > I noticed that the functions hash-table-keys and hash-table-values are
> > just wrappers around maphash. This means that there is no way to
> > iterate over a hash-table without using a lambda.
>
> If this is about syntax, cl-loop has support for hash tables. For
> example
>
>   for x being the hash-keys of something using (hash-value y)
>
>
>

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