+ /* In a series of synonyms, present the most meaning full first, so
+ that argmatch_valid be more readable. */
+ "none", "off",
+ "simple", "never",
+ "existing", "nil",
+ "numbered", "t",
+ 0
+};
+
+static const enum backup_type backup_types[] =
+{
+ none, none,
+ simple, simple,
+ numbered_existing, numbered_existing,
+ numbered, numbered
+};
+
+/* Return the type of backup specified by VERSION.
+ If VERSION is NULL or the empty string, return numbered_existing.
+ If VERSION is invalid or ambiguous, fail with a diagnostic appropriate
+ for the specified CONTEXT. Unambiguous abbreviations are accepted. */
+
+enum backup_type
+get_version (const char *context, const char *version)
+{
+ if (version == 0 || *version == 0)
+ return numbered_existing;
+ else
+ return XARGMATCH (context, version, backup_args, backup_types);
+}