Re: moving more cl seq/mapping support into core

[Richard Stallman]

    Those functions are not there overnight they probably came from people's
    years of experience using and designing lisp. So they will be reinvented
    from time to time for writing any non-trivial elisp packages except now
    we have slightly different versions here and there.

    My wish is all of them should be incorporated into elisp.

Since they would occupy parts of the address space that users expect
is theirs, we would need to document them all in the Lisp manual.

Aside from that, the keyword-based interfaces of these functions
does not fit the style of Emacs Lisp very well.