Subject: ediff

From: Peter Blicher <[email-masked]>
Date: Tue, 30 Jul 1996 14:02:29 -0400

I'm still having trouble getting ediff to work.  Using nt 3.51, pentium
pro, emacs 19.31.

I read the messages from:

ediff 
            George V. Reilly Tue, 16 Jul 96 14:25:00 PDT 
            Kenneth L. Degrant II Tue, 16 Jul 1996 12:41:04 -0400 
            Jean-Paul De Feyter Thu, 11 Jul 1996 23:53:13 +0100 
            Kenneth L. Degrant II Wed, 10 Jul 1996 07:57:55 -0400 

The first problem, which I was able to solve, was that the diff program I
am using (cygnus diff) cannot parse the drive letter in things of the form
"c:/foo/bar/baz".   It is, however, perfectly happy with forward slashes.
In fact, since I don't think it likes backslashes, the 'dosify-filename'
hack might be malignant in this case.

However, although I can get diff to work ok, I can't get ediff to be happy
with what it produces.  In particular it barfs on the first line of output,
which is "35c35^M".  I do not know if ediff is barfing on the format of
this diff, or on the ctrl M that ends each line.  Unfortunately, I don't
think it's clearly documented what kind of diff output ediff expects, and I
do not have any documents that tell the exact form of output that any
particular diff is supposed to produce.  I suppose I could hack ediff's
regexps for parsing the diff, but therein lie dragons and great danger.

I've tried running this in an inferior shell using cmd.exe and cygnus bash,
and both give the same behavior.

Can anyone tell me what the specific problem is (e.g. ^M, wrong diff
format, bug in cygnus diff, etc.) so I don't spend time chasing ghosts?

(If the problem is the ^M's, then there is a larger problem of whose
responsibility it is to get rid of them.  My opinion is that no client code
(such as ediff) should ever have to look at them, and they should always be
stripped by anything (or an interposed filter) that might produce them.
However, that may require too much smarts about guessing what should be in
the output.)

Thanks.

--peter

-- 
A. Peter Blicher	NEC Research Institute
609-951-2716		4 Independence Way
609-951-2488 fax	Princeton, NJ  08540