bug#73431: Add `setf` support for `stream.el` in ELPA

[Michael Heerdegen via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Okamsn via "Bug reports for GNU Emacs, the Swiss army knife of text
editors" <bug-gnu-emacs@gnu.org> writes:

> Please see the attached file. It changes streams to be structs, warns
> that streams are not mutable, adds a creation method for arrays that
> doesn't create intermediate sub-arrays, and adds some methods for
> streams for more of the seq.el functions.

Thank you for working on this.

> * stream.el (stream): Define the structure using 'cl-defstruct'.

Does changing the internal representation of streams have an effect
on the speed of the run code?

> * stream.el (seq-sort, seq-reverse, seq-concatenate, seq-remove-at-position):
> Add methods that did not work as expected with the generic implementation.

I don't like these, apart from seq-concatenate.

That we have a unified interface for different types of seqs doesn't
mean we must implement every functionality for every type - we can limit
to those where it makes sense.  If you have to translate the complete
stream into an intermediate seq type to implement a feature (like
sorting) hints at that it might not make sense.  And I think indeed: if
you need to sort any data than you probably should not use streams to
represent them at all.  In the rare cases where this really makes sense
conceptually it is even better to do the translation into a different
seq type explicitly.  Converting the result back into a delayed list
makes hardly sense.  This is inefficient and leads to bad style.


Michael.