Re: What's missing in ELisp that makes people want to use cl-lib?

[Adam Porter]

> Do people really want `cl-pushnew', with its keyword arguments?
> Or would a simple `pushnew' be even more pleasing?

It might be more aesthetically or ideologically pleasing, but it would 
be much less useful.  :test is often necessary for using EQUAL (as EQ is 
often the wrong function to use); without it, a hypothetical non-CL 
PUSHNEW function would often be unusable.  And :key makes it easy to use 
with, e.g. structs' accessor functions (which are very helpful for 
developers as they allow compile-time checking, completion, etc).

When CL-PUSHNEW is called without keyword arguments, it's as simple as a 
hypothetical non-CL PUSHNEW that offered no keyword arguments.  The 
keyword arguments provide optional flexibility; without them, one would 
have to write a much larger, more complex form to do the same things.

Finally, if there were an additional, non-CL PUSHNEW function added, I 
would think that would be much more confusing to users, especially new 
ones, for there to be a difference in behavior between PUSHNEW and 
CL-PUSHNEW.

So I would ask that CL-PUSHNEW become PUSHNEW as-is.

> To define `pushnew' in Emacs Lisp, and document it in the Emacs Lisp
> Reference Manual, would be much cleaner than spreading the use of
> cl-lib to more files.

I would be happy to see more cl-lib functions "moved" back into "core" 
Elisp.  Using Elisp without cl-lib feels restrictive to me.

By the way, with regard to CL-PUSHNEW, it seems surprising that no one's 
mentioned the existing counterpart in "core" Elisp, ADD-TO-LIST. 
Notably, its docstring says:

  This is handy to add some elements to configuration variables,
  but please do not abuse it in Elisp code, where you are usually
  better off using ‘push’ or ‘cl-pushnew’.

So even "core", non-cl-lib Elisp recommends the use of some cl-lib 
functions, i.e. CL-PUSHNEW.  That certainly suggests a "gap" in core 
Elisp functionality.

--Adam