library prefixes (versus other name prefixes)

library prefixes (versus other name prefixes)

[Drew Adams]

Some of the discussion in threads "handling many
matches", "Imports / inclusion of s.el into Emacs",
and now "Add some aliases for re-related functions"
considers the use of a thing-type name as prefix
for function, var, etc. names.

For example, it's proposed to add aliases that
use prefix `re-' for regexp-related functions.

Currently, I see only these functions with that
prefix:

 re-builder  (command)
 re-search-backward  (command)
 re-search-backward-lax-whitespace 
 re-search-forward  (command)
 re-search-forward-lax-whitespace

I asked myself the question, "What if someone
wanted to add a library/package that uses
prefix `re-'? Already taken, in effect, and
not for a library.  Too bad.

How do we tell a library prefix from another
kind of prefix, including one that refers to
a type of thing returned or accepted as arg?

We can't, on the face of it.

So I wonder if it isn't time to reconsider the
convention of ending a library prefix with `-'.

I know that some libraries out there do use
a different char, in particular `/'.  Should
we change to that?  (I'm thinking maybe yes.)

If so, should we rename existing library
prefixes to respect that new convention?
(I'd say no.)
___

What about this proposal:

1. Change the library-prefix convention to use
   `/' instead of `-'.

   So instead of `mylib-foo' the name would be
   `mylib/foo'.

2. Say that the prefix should have at least 2
   chars, besides the `/'.

   So `s/foo' and `/foo' wouldn't conform.

3. "Internal" names would still use `-', after
   the prefix.

   So instead of `mylib--foo' the name would
   be `mylib/-foo'.

What would be some pros & cons in making such a change?

Re: library prefixes (versus other name prefixes)

[Adam Porter]

If I may offer a perspective from "MELPA land" (though I am not MELPA,
just a contributor):

MELPA has not always required that submitted packages strictly adhere to
the Elisp manual's conventions, so some older packages do use a slash as
a prefix separator.

New packages are frequently submitted which use a slash separator.  Now,
MELPA requires them to replace the slash with a hyphen, as the Elisp
manual recommends.  Sometimes the package authors are very reluctant to
do so.

Some built-in Emacs packages also use a slash separator, like pcomplete
(although it seems to use it only for generated completion functions,
not library functions).

Some MELPA packages also use a colon as a separator, like Hydra
(although, like pcomplete, it seems to use it only for generated Hydra
functions).

In my own non-MELPA code, I use a slash separator.  For me, it's more
visually distinctive than a hyphen and makes it easier to discern the
prefix part of the symbol.

So, I would be glad if the official Elisp conventions allowed a slash
separator, and I think many other Elisp package authors would as well.

This topic frequently comes up in discussion on reddit.com/r/emacs,
which is read by many users and package authors, so I've linked this
thread there:

https://old.reddit.com/r/emacs/comments/gcrwic/the_symbolprefixseparatormustbeahyphen_topic/