Re: coreutils sort

[Paul Eggert]

Christian writes:

> sort -nt. +0 -1 +1 -2 +2 -3 +3 -4
> ...
> I've been using that command syntax to sort IP's for several years...

Come to think of it, GNU sort could support that syntax even when
asked to have POSIX 1003.1-2001 semantics, so long as argument
reordering is in effect, since as far as POSIX is concerned "-1" is an
option that lets 'sort' do what it wants.  I installed the following
patch, so that the above example will still work for you.  Most of the
code change is just for reindenting.

2006-06-28  Paul Eggert  <address@hidden>

        * NEWS: Support obsolete usages like "sort +1 -2" even when
        conforming to POSIX 1003.1-2001, since this is a pure extension to
        POSIX.  Problem reported by Christian in:
        http://lists.gnu.org/archive/html/bug-coreutils/2006-06/msg00220.html
        * doc/coreutils.texi (sort invocation): Document this.
        * src/sort.c (main): Implement this.

Index: NEWS
===================================================================
RCS file: /fetish/cu/NEWS,v
retrieving revision 1.387
diff -p -u -r1.387 NEWS
--- NEWS        26 Jun 2006 13:02:01 -0000      1.387
+++ NEWS        28 Jun 2006 23:47:03 -0000
@@ -77,6 +77,10 @@ GNU coreutils NEWS                      
   sort now reports incompatible options (e.g., -i and -n) rather than
   silently ignoring one of them.
 
+  sort now supports obsolete usages like "sort +1 -2" when conforming
+  to POSIX 1003.1-2001, since this is a pure extension to POSIX.
+  However, "sort +1" still sorts the file named "+1".
+
   stat's --format=FMT option now works the way it did before 5.3.0:
   FMT is automatically newline terminated.  The first stable release
   containing this change was 5.92.
Index: doc/coreutils.texi
===================================================================
RCS file: /fetish/cu/doc/coreutils.texi,v
retrieving revision 1.333
diff -p -u -r1.333 coreutils.texi
--- doc/coreutils.texi  27 Jun 2006 20:26:12 -0000      1.333
+++ doc/coreutils.texi  28 Jun 2006 23:47:06 -0000
@@ -3681,11 +3681,13 @@ numbers of leading blanks in fields can 
 Keys can span multiple fields.
 
 @vindex _POSIX2_VERSION
address@hidden POSIXLY_CORRECT
 On older systems, @command{sort} supports an obsolete origin-zero
 syntax @address@hidden address@hidden for specifying sort keys.
 This obsolete behavior can be enabled or disabled with the
 @env{_POSIX2_VERSION} environment variable (@pxref{Standards
-conformance}).
+conformance}); it can also be enabled when @env{POSIXLY_CORRECT} is
+not set by using the obsolete syntax with @address@hidden present.
 
 Scripts intended for use on standard hosts should avoid obsolete
 syntax and should use @option{-k} instead.  For example, avoid
Index: src/sort.c
===================================================================
RCS file: /fetish/cu/src/sort.c,v
retrieving revision 1.336
diff -p -u -r1.336 sort.c
--- src/sort.c  25 May 2006 16:47:43 -0000      1.336
+++ src/sort.c  28 Jun 2006 23:47:06 -0000
@@ -2320,37 +2320,42 @@ main (int argc, char **argv)
        {
        case 1:
          key = NULL;
-         if (obsolete_usage && optarg[0] == '+')
+         if (optarg[0] == '+')
            {
-             /* Treat +POS1 [-POS2] as a key if possible; but silently
-                treat an operand as a file if it is not a valid +POS1.  */
-             key = new_key ();
-             s = parse_field_count (optarg + 1, &key->sword, NULL);
-             if (s && *s == '.')
-               s = parse_field_count (s + 1, &key->schar, NULL);
-             if (! (key->sword | key->schar))
-               key->sword = SIZE_MAX;
-             if (! s || *set_ordering (s, key, bl_start))
+             bool minus_pos_usage = (optind != argc && argv[optind][0] == '-'
+                                     && ISDIGIT (argv[optind][1]));
+             obsolete_usage |= minus_pos_usage & ~posixly_correct;
+             if (obsolete_usage)
                {
-                 free (key);
-                 key = NULL;
-               }
-             else
-               {
-                 if (optind != argc && argv[optind][0] == '-'
-                     && ISDIGIT (argv[optind][1]))
+                 /* Treat +POS1 [-POS2] as a key if possible; but silently
+                    treat an operand as a file if it is not a valid +POS1.  */
+                 key = new_key ();
+                 s = parse_field_count (optarg + 1, &key->sword, NULL);
+                 if (s && *s == '.')
+                   s = parse_field_count (s + 1, &key->schar, NULL);
+                 if (! (key->sword | key->schar))
+                   key->sword = SIZE_MAX;
+                 if (! s || *set_ordering (s, key, bl_start))
+                   {
+                     free (key);
+                     key = NULL;
+                   }
+                 else
                    {
-                     char const *optarg1 = argv[optind++];
-                     s = parse_field_count (optarg1 + 1, &key->eword,
+                     if (minus_pos_usage)
+                       {
+                         char const *optarg1 = argv[optind++];
+                         s = parse_field_count (optarg1 + 1, &key->eword,
                                             N_("invalid number after `-'"));
-                     if (*s == '.')
-                       s = parse_field_count (s + 1, &key->echar,
+                         if (*s == '.')
+                           s = parse_field_count (s + 1, &key->echar,
                                               N_("invalid number after `.'"));
-                     if (*set_ordering (s, key, bl_end))
-                       badfieldspec (optarg1,
+                         if (*set_ordering (s, key, bl_end))
+                           badfieldspec (optarg1,
                                      N_("stray character in field spec"));
+                       }
+                     insertkey (key);
                    }
-                 insertkey (key);
                }
            }
          if (! key)