bug#15171: 24.3.50; (cl) `Common Lisp Compatibility' is incomplete

bug#15171: 24.3.50; (cl) `Common Lisp Compatibility' is incomplete

[Drew Adams]

This appendix is only a brief summary, it seems, and can be quite
misleading.  I'm skeptical that it specifies "a list of all known
incompatibilities" between the Emacs cl* libraries and Common Lisp.

But it is correct that it _should_ specify them all.

For one thing, the handling of formal parameters that correspond to
special variables is an unmentioned incompatibility.  State that
you must use an explicit `let' inside the function to get the same
effect.

Likewise, the difference in syntax for characters, various other data
type differences, and the absence of read macros.  Not to mention CLOS.

The main message for this appendix should not be that the few things
that it mentions are the only incompatibilities, but rather that even
with cl* Emacs Lisp is quite different from Common Lisp.  IOW, it
gives exactly the wrong message, suggesting that the two are almost
the same.

This appendix should at least mention:

1. All important or large Common Lisp features that are lacking.

2. All important differences in behavior for features that might
seem at first sight to be the same or similar.

An additional detail - this text is backwards:

"The multiple-value return facility treats lists as multiple values,
                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
since Emacs Lisp cannot support multiple return values directly."

It should say that because Elisp cannot support... it treats multiple
values as lists.

And "treats" is even too generous.  It should just say that Emacs
Lisp does not support binding or returning multiple values; instead,
it uses lists of values.


In GNU Emacs 24.3.50.1 (i686-pc-mingw32)
 of 2013-08-17 on ODIEONE
Bzr revision: 113938 eliz@gnu.org-20130817171807-fxigtkbc6yy8m9iw
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --prefix=/c/Devel/emacs/binary --enable-checking=yes,glyphs
 CFLAGS=-O0 -g3 LDFLAGS=-Lc:/Devel/emacs/lib
 CPPFLAGS=-Ic:/Devel/emacs/include'

bug#15171: 24.3.50; (cl) `Common Lisp Compatibility' is incomplete

[Lars Ingebrigtsen]

Drew Adams <drew.adams@oracle.com> writes:

> This appendix is only a brief summary, it seems, and can be quite
> misleading.  I'm skeptical that it specifies "a list of all known
> incompatibilities" between the Emacs cl* libraries and Common Lisp.
>
> But it is correct that it _should_ specify them all.

Or we could just change the line "The following is a list of all known
incompatibilities between this package and Common Lisp as documented in
Steele" to "a list of some of the more glaring incompatibilities"...

-- 
(domestic pets only, the antidote for overdose, milk.)
  bloggy blog http://lars.ingebrigtsen.no/

bug#15171: 24.3.50; (cl) `Common Lisp Compatibility' is incomplete

[Drew Adams]

> > This appendix is only a brief summary, it seems, and can be quite
> > misleading.  I'm skeptical that it specifies "a list of all known
> > incompatibilities" between the Emacs cl* libraries and Common
> > Lisp.
> >
> > But it is correct that it _should_ specify them all.
> 
> Or we could just change the line "The following is a list of all
> known incompatibilities between this package and Common Lisp as
> documented in Steele" to "a list of some of the more glaring
> incompatibilities"...

Some of the most _important_, OK.  But don't necessarily think
you've found an easy way to fix this bug.  The list would then
need to be fixed to specify the most important differences.

That might be easier that a comprehensive list of all differences,
but it is not trivial.  And it is not enough to suppose that the
list as it stands now is adequate in that regard either.

And no, not "most glaring", i.e., most obvious.  Users need
doc especially for what is not so obvious.  Most important, OK.
Most glaring, no.

bug#15021: bug#15171: 24.3.50; (cl) `Common Lisp Compatibility' is incomplete

[Lars Ingebrigtsen]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> Drew Adams <drew.adams@oracle.com> writes:
>
>> This appendix is only a brief summary, it seems, and can be quite
>> misleading.  I'm skeptical that it specifies "a list of all known
>> incompatibilities" between the Emacs cl* libraries and Common Lisp.
>>
>> But it is correct that it _should_ specify them all.
>
> Or we could just change the line "The following is a list of all known
> incompatibilities between this package and Common Lisp as documented in
> Steele" to "a list of some of the more glaring incompatibilities"...

I've now committed a similar wording.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no