String.join revisited (URGENT for 1.6)

[Juergen A. Erhard]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Okay, so I was using the sort method on a list of integers.  And I
wondered how the *list* knows how to sort both a list of integers and
a list of strings.

The answer (okay we all know that): it doesn't.  It just call cmp for
two elements, and voila... *they* know how to compare themselves to
each other.

So what's this got to do with string.join (or "string".join)?

Simple: many folks have said in the past days/weeks (since this
"string".join(list) came up) that they'd be a lot more comfortable
with s.th. like

    [list].join(separator)

But others have contested this saying it would put string knowledge
into lists (or rather sequences... which do not exactly exist[1])

Well, if we'd give strings a "join" method that looked like

   "some string".join("another string", "separator")

then [some list].join would simple invoke that (reduce(__join__, [some
list])).  And throw an exception if the items in the list don't know
how to join themselves join.

Bye, J

PS: I fully expect for this to be too late to be changed in 1.6... I
can still hope, though.  Either it happens now, or not at all... or we
need another name like "append" ;-)

PPS: Sorry, no patch, and it's probably slower than the current ugly
"string".join.  But I rather choose a usable, `nice' design over speed
any time.  And the speed can be improved if ".join" could take a list
of items as first argument (like "string".join(["list", "of",
"strings"], "sep")).  Yes, that's almost the same as the current
string.join() ;-)

[1] I hope the (eventual, hopefully) merging of types and classes will
remedy this.  Lists and tuples and strings have to be subclasses of a
sequence class (we can learn something from the Common Lisp hierarchy
I think).  Oh, and that merge would also make UserList/Dict/String
obsolete, yay!

- -- 
Jürgen A. Erhard      eMail: jae at ilk.de      phone: (GERMANY) 0721 27326
          My WebHome: http://members.tripod.com/Juergen_Erhard
       SPACE: Above And Beyond (http://www.planetx.com/space:aab)
          Codito, ergo sum - I code, therefore I am -- Raster
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.0.1 (GNU/Linux)
Comment: Use Mailcrypt and GnuPG <http://www.gnupg.org/>

iEYEARECAAYFAjkxOjoACgkQN0B+CS56qs3HeQCgjjEJF/7EHY41FdEv9ENoPw0e
3vcAnil3uOGlNYcKP2jRO/z3Lnz3AWjD
=OdFE
-----END PGP SIGNATURE-----