b4_args is more general than only C++.

[bison.git] / src / getargs.c

diff --git a/src/getargs.c b/src/getargs.c
index 2a0611bc315ac9a245c539b0556e78c6637d33ea..cff6ff3fecdb553d679d7e8ec3999eaedd4ac4a5 100644 (file)
--- a/src/getargs.c
+++ b/src/getargs.c
@@ -87,10 +87,12 @@ char *program_name;
  *  \param keys     array of valid subarguments.
  *  \param values   array of corresponding (int) values.
  *  \param flags    the flags to update
- *  \param args     colon separated list of effective subarguments to decode.
+ *  \param args     comma separated list of effective subarguments to decode.
  *                  If 0, then activate all the flags.
  *
- *  The special value 0 resets the flags to 0.
+ *  If VALUE != 0 then KEY sets flags and no-KEY clears them.
+ *  If VALUE == 0 then KEY clears all flags and no-KEY sets all flags.
+ *  Thus no-none = all and no-all = none.
  */
 static void
 flags_argmatch (const char *option,
@@ -102,11 +104,18 @@ flags_argmatch (const char *option,
       args = strtok (args, ",");
       while (args)
        {
-         int value = XARGMATCH (option, args, keys, values);
+         int no = strncmp (args, "no-", 3) == 0 ? 3 : 0;
+         int value = XARGMATCH (option, args + no, keys, values);
          if (value == 0)
-           *flags = 0;
+           if (no)
+             *flags = ~0;
+           else
+             *flags = 0;
          else
-           *flags |= value;
+           if (no)
+             *flags &= ~value;
+           else
+             *flags |= value;
          args = strtok (NULL, ",");
        }
     }
@@ -248,6 +257,11 @@ usage (int status)
             program_name);
   else
     {
+      /* For ../build-aux/cross-options.pl to work, use the format:
+               ^  -S, --long[=ARGS] (whitespace)
+        A --long option is required.
+        Otherwise, add exceptions to ../build-aux/cross-options.pl.  */
+
       printf (_("Usage: %s [OPTION]... FILE\n"), program_name);
       fputs (_("\
 Generate LALR(1) and GLR parsers.\n\