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

[Tomas Hlavaty <tom@logand.com>]

On Fri 29 Nov 2024 at 15:25, Shankar Rao <shankar.rao@gmail.com> wrote:
> while the latter require a lambda, which are generally slower and
> harder to debug.

If that is the case then it would be better to improve the debuger.

>> This means that there is no way to iterate over a hash-table without
>> using a lambda.

Iterating over a hash-table using a callback is not such a problem.

More interesting is that it is not possible to suspend and resume the
iteration.  And even more interesting is that it is generally undefined
to change the hash-table inside map-hash callback.  hash-tables are
complex objects compared to lists or arrays and map-hash hides a lot of
complexity trying to provide reasonable interface.

Even worse is the lisp interface to list directory,
e.g. directory-files, directory-files-and-attributes,
directory-files-recursively.  Here one gets the whole thing as a list
all at once.  And the filter is quite limited and not programable.  So
if I want something uncommon or faster, an external program is likely a
better choice.  Compare that to C/POSIX interface which provides a way
to iterate over the directory.  Or maybe instead of worrying about
closing files, a map-hash like interface, e.g. map-directory, would be
better?