--- sdiff.c_orig	Tue Aug 31 19:38:21 2004
+++ sdiff.c	Tue Aug 31 19:41:09 2004
@@ -40,6 +40,11 @@
 #define DEFAULT_EDITOR_PROGRAM "ed"
 #endif
 
+/* Default sdiff keys for merging, in addition to historical 'l'/'r'. */
+#ifndef DEFAULT_MERGE_KEYS
+#define DEFAULT_MERGE_KEYS "12"
+#endif
+
 extern char version_string[];
 static char const *program_name;
 static char const *diffbin = DIFF_PROGRAM;
@@ -48,6 +53,8 @@
 
 static char *tmpname;
 static int volatile tmpmade;
+static char leftkey;
+static char rightkey;
 
 #if HAVE_FORK
 static pid_t volatile diffpid;
@@ -60,6 +67,7 @@
 static VOID *xmalloc PARAMS((size_t));
 static char const *expand_name PARAMS((char *, int, char const *));
 static int edit PARAMS((struct line_filter *, int, struct line_filter *, int, FILE*));
+static int calleditor PARAMS((int, struct line_filter *, int, struct line_filter *, int, FILE*));
 static int interact PARAMS((struct line_filter *, struct line_filter *, struct line_filter *, FILE*));
 static int lf_snarf PARAMS((struct line_filter *, char *, size_t));
 static int skip_white PARAMS((void));
@@ -401,7 +409,8 @@
   int opt;
   char *editor;
   char *differ;
-
+  char *keys;
+  
   initialize_main (&argc, &argv);
   program_name = argv[0];
 
@@ -414,6 +423,15 @@
 
   diffarg ("diff");
 
+  keys = getenv("SDIFF_MERGE_KEYS");
+  if (keys && strlen(keys) == 2) {
+    leftkey = keys[0];         
+    rightkey = keys[1];
+  } else {
+    leftkey = DEFAULT_MERGE_KEYS[0];
+    rightkey = DEFAULT_MERGE_KEYS[1];
+  }
+
   /* parse command line args */
   while ((opt = getopt_long (argc, argv, "abBdHiI:lo:stvw:W", longopts, 0))
 	 != EOF)
@@ -794,10 +813,10 @@
 static void
 give_help ()
 {
-  fprintf (stderr,"l:\tuse the left version\n");
-  fprintf (stderr,"r:\tuse the right version\n");
-  fprintf (stderr,"e l:\tedit then use the left version\n");
-  fprintf (stderr,"e r:\tedit then use the right version\n");
+  fprintf (stderr,"l or %c:\tuse the left version\n", leftkey);
+  fprintf (stderr,"r or %c:\tuse the right version\n", rightkey);
+  fprintf (stderr,"e %c:\tedit then use the left version\n", leftkey);
+  fprintf (stderr,"e %c:\tedit then use the right version\n", rightkey);
   fprintf (stderr,"e b:\tedit then use the left and right versions concatenated\n");
   fprintf (stderr,"e:\tedit a new version\n");
   fprintf (stderr,"s:\tsilently include common lines\n");
@@ -841,197 +860,152 @@
      int lenr;
      FILE *outfile;
 {
-  for (;;)
-    {
-      int cmd0, cmd1;
-      int gotcmd = 0;
-
-      cmd1 = 0; /* Pacify `gcc -W'.  */
-
-      while (!gotcmd)
-	{
-	  if (putchar ('%') != '%')
-	    perror_fatal ("output error");
-	  ck_fflush (stdout);
-
-	  cmd0 = skip_white ();
-	  switch (cmd0)
-	    {
-	    case 'l': case 'r': case 's': case 'v': case 'q':
-	      if (skip_white () != '\n')
-		{
-		  give_help ();
-		  flush_line ();
-		  continue;
-		}
-	      gotcmd = 1;
-	      break;
-
-	    case 'e':
-	      cmd1 = skip_white ();
-	      switch (cmd1)
-		{
-		case 'l': case 'r': case 'b':
-		  if (skip_white () != '\n')
-		    {
-		      give_help ();
-		      flush_line ();
-		      continue;
-		    }
-		  gotcmd = 1;
-		  break;
-		case '\n':
-		  gotcmd = 1;
-		  break;
-		default:
-		  give_help ();
-		  flush_line ();
-		  continue;
-		}
-	      break;
-	    case EOF:
-	      if (feof (stdin))
-		{
-		  gotcmd = 1;
-		  cmd0 = 'q';
-		  break;
-		}
-	      /* falls through */
-	    default:
-	      flush_line ();
-	      /* falls through */
-	    case '\n':
-	      give_help ();
-	      continue;
-	    }
-	}
-
-      switch (cmd0)
-	{
-	case 'l':
-	  lf_copy (left, lenl, outfile);
-	  lf_skip (right, lenr);
-	  return 1;
-	case 'r':
-	  lf_copy (right, lenr, outfile);
-	  lf_skip (left, lenl);
-	  return 1;
-	case 's':
-	  suppress_common_flag = 1;
-	  break;
-	case 'v':
-	  suppress_common_flag = 0;
-	  break;
-	case 'q':
-	  return 0;
-	case 'e':
-	  {
-	    int tfd;
-	    FILE *tmp;
-
-	    if (tmpmade)
-	      {
-	        unlink (tmpname);
-	        tmpmade = 0;
-		free (tmpname);
-	      }
-
-	    asprintf (&tmpname, "%s/sdiff.XXXXXX",
-	      getenv("TMPDIR") ?: P_tmpdir);
-	    if (tmpname == NULL)
-	      perror_fatal ("temporary file name");
-	    tfd = mkstemp(tmpname);
-	    if (tfd == -1)
-	      perror_fatal ("temporary file name");
-	    tmp = fdopen (tfd, "w+");
-	    if (tmp == NULL)
-	      perror_fatal ("temporary file name");
- 
-	    tmpmade = 1;
-
-	    if (cmd1 == 'l' || cmd1 == 'b')
-	      lf_copy (left, lenl, tmp);
-	    else
-	      lf_skip (left, lenl);
-
-	    if (cmd1 == 'r' || cmd1 == 'b')
-	      lf_copy (right, lenr, tmp);
-	    else
-	      lf_skip (right, lenr);
-
-	    ck_fflush (tmp);
+  int cmd0, cmd1 = 0;
+  
+  for (;;) {
+    if (putchar ('%') != '%')
+      perror_fatal ("output error");
+    ck_fflush (stdout);
+    
+    cmd0 = skip_white();
+    if ((cmd0 == EOF) || (feof (stdin))) return 0;
+    
+    if ((cmd0 == 'l') || (cmd0 == leftkey)) {
+      lf_copy (left, lenl, outfile);
+      lf_skip (right, lenr);
+      flush_line();
+      return 1;
+    } else if ((cmd0 == 'r') || (cmd0 == rightkey)) {
+      lf_copy (right, lenr, outfile);
+      lf_skip (left, lenl);
+      flush_line();
+      return 1;
+    } else if (cmd0 == 's') {
+      suppress_common_flag = 1;
+    } else if (cmd0 == 'v') {
+      suppress_common_flag = 0;
+    } else if (cmd0 == 'q') {
+      return 0;
+    } else if (cmd0 == 'e') {
+      cmd1 = skip_white();
+      if ((cmd1 == leftkey) || (cmd1 == rightkey) ||
+          (cmd1 == 'l') || (cmd1 == 'r') || (cmd1 == 'b') || (cmd1 == '\n')) {
+        flush_line();        
+        return calleditor(cmd1, left, lenl, right, lenr, outfile);
+      } else {
+        give_help();
+      }
+    } else if (cmd0 == '\n') {
+      continue;
+    } else {
+      give_help();
+    }
+    flush_line();        
+  }
+}
 
-	    {
-	      int wstatus;
+/* Invoke the user's preferred editor on the data to be merged. */
+int calleditor(cmd1, left, lenl, right, lenr, outfile)
+     int cmd1;
+     struct line_filter *left;
+     int lenl;
+     struct line_filter *right;
+     int lenr;
+     FILE *outfile;
+{
+  int tfd;
+  FILE *tmp;
+  
+  if (tmpmade) {
+    unlink (tmpname);
+    tmpmade = 0;
+    free (tmpname);
+  }
+  
+  asprintf(&tmpname, "%s/sdiff.XXXXXX", getenv("TMPDIR") ?: P_tmpdir);
+  if (tmpname == NULL)
+    perror_fatal ("temporary file name");
+  tfd = mkstemp(tmpname);
+  if (tfd == -1)
+    perror_fatal ("temporary file name");
+  tmp = fdopen (tfd, "w+");
+  if (tmp == NULL)
+    perror_fatal ("temporary file name");    
+  tmpmade = 1;
+  
+  if ((cmd1 == leftkey) || (cmd1 == 'l') || (cmd1 == 'b'))
+    lf_copy (left, lenl, tmp);
+  else
+    lf_skip (left, lenl);
+  
+  if ((cmd1 == rightkey) || (cmd1 == 'r') || (cmd1 == 'b'))
+    lf_copy (right, lenr, tmp);
+  else
+    lf_skip (right, lenr);
+  
+  ck_fflush (tmp);
+  
+  {
+    int wstatus;
 #if ! HAVE_FORK
-	      char *command = xmalloc (strlen (edbin) + strlen (tmpname) + 2);
-	      sprintf (command, "%s %s", edbin, tmpname);
-	      wstatus = system (command);
-	      free (command);
+    char *command = xmalloc (strlen (edbin) + strlen (tmpname) + 2);
+    sprintf (command, "%s %s", edbin, tmpname);
+    wstatus = system (command);
+    free (command);
 #else /* HAVE_FORK */
-	      pid_t pid;
-
-	      ignore_SIGINT = 1;
-	      checksigs ();
-
-	      pid = vfork ();
-	      if (pid == 0)
-		{
-		  char const *argv[3];
-		  int i = 0;
-
-		  argv[i++] = edbin;
-		  argv[i++] = tmpname;
-		  argv[i++] = 0;
-
-		  execvp (edbin, (char **) argv);
-		  write (STDERR_FILENO, edbin, strlen (edbin));
-		  write (STDERR_FILENO, ": not found\n", 12);
-		  _exit (1);
-		}
-
-	      if (pid < 0)
-		perror_fatal ("fork failed");
-
-	      while (waitpid (pid, &wstatus, 0) < 0)
-		if (errno == EINTR)
-		  checksigs ();
-		else
-		  perror_fatal ("wait failed");
-
-	      ignore_SIGINT = 0;
+    pid_t pid;
+    
+    ignore_SIGINT = 1;
+    checksigs ();
+    
+    pid = vfork ();
+    if (pid == 0) {
+      char const *argv[3];
+      int i = 0;
+      
+      argv[i++] = edbin;
+      argv[i++] = tmpname;
+      argv[i++] = 0;
+      
+      execvp (edbin, (char **) argv);
+      write (STDERR_FILENO, edbin, strlen (edbin));
+      write (STDERR_FILENO, ": not found\n", 12);
+      _exit (1);
+    }
+    
+    if (pid < 0)
+      perror_fatal ("fork failed");
+    
+    while (waitpid (pid, &wstatus, 0) < 0)
+      if (errno == EINTR)
+        checksigs ();
+      else
+        perror_fatal ("wait failed");
+    
+    ignore_SIGINT = 0;
 #endif /* HAVE_FORK */
-
-	      if (wstatus != 0)
-		fatal ("Subsidiary editor failed");
-	    }
-
-	    if (fseek (tmp, 0L, SEEK_SET) != 0)
-	      perror_fatal ("fseek");
-	    {
-	      /* SDIFF_BUFSIZE is too big for a local var
-		 in some compilers, so we allocate it dynamically.  */
-	      char *buf = xmalloc (SDIFF_BUFSIZE);
-	      size_t size;
-
-	      while ((size = ck_fread (buf, SDIFF_BUFSIZE, tmp)) != 0)
-		{
-		  checksigs ();
-		  ck_fwrite (buf, size, outfile);
-		}
-	      ck_fclose (tmp);
-
-	      free (buf);
-	    }
-	    return 1;
-	  }
-	default:
-	  give_help ();
-	  break;
-	}
+    
+    if (wstatus != 0)
+      fatal ("Subsidiary editor failed");
+  }
+  
+  if (fseek (tmp, 0L, SEEK_SET) != 0)
+      perror_fatal ("fseek");
+  {
+    /* SDIFF_BUFSIZE is too big for a local var
+       in some compilers, so we allocate it dynamically.  */
+    char *buf = xmalloc (SDIFF_BUFSIZE);
+    size_t size;
+    
+    while ((size = ck_fread (buf, SDIFF_BUFSIZE, tmp)) != 0) {
+      checksigs ();
+      ck_fwrite (buf, size, outfile);
     }
+    ck_fclose(tmp);
+    free (buf);
+  }
+  return 1;
 }
-
 
 
 /* Alternately reveal bursts of diff output and handle user commands.  */