cli: use designated initializers for opt desc

Several changes at once, just to not have to change the same lines
several times over:

- Use designated initializers to initialize opt desc arrays.

- Only initialize the needed fields.

- Remove arg_id (short options) as unused.

- Replace opt_type and output_var with several type safe output
  variables, where the output variable being non-NULL determines the
  type. Introduce checks to ensure only one is set. The downside is
  some waste of const space per argument; this could be saved by
  retaining opt_type and using a union, but that's still pretty
  verbose.

- Fix some variables due to the type safety. Mostly a good thing, but
  leads to some enums being changed to ints. This is pedantically
  correct, but somewhat annoying. We could also cast, but that defeats
  the purpose a bit.

- Terminate the opt desc arrays using {}.

The output variable type safety and the ability to add new fields for
just some output types or arguments are the big wins. For example, if
we wanted to add a variable to set when the argument is present, we
could do so for just the arguments that need it.

Beauty is in the eye of the beholder, but I think this looks nice when
defining the arguments, and reduces some of the verbosity we have
there.

1 files changed, 11 insertions, 11 deletions

diff --git a/notmuch.c b/notmuch.c
index 201c7454..cc9c34ae 100644
--- a/notmuch.c
+++ b/notmuch.c
@@ -47,13 +47,13 @@ static int
 _help_for (const char *topic);
 
 static notmuch_bool_t print_version = FALSE, print_help = FALSE;
-char *notmuch_requested_db_uuid = NULL;
+const char *notmuch_requested_db_uuid = NULL;
 
 const notmuch_opt_desc_t notmuch_shared_options [] = {
-    { NOTMUCH_OPT_BOOLEAN, &print_version, "version", 'v', 0 },
-    { NOTMUCH_OPT_BOOLEAN, &print_help, "help", 'h', 0 },
-    { NOTMUCH_OPT_STRING, &notmuch_requested_db_uuid, "uuid", 'u', 0 },
-    {0, 0, 0, 0, 0}
+    { .opt_bool = &print_version, .name = "version" },
+    { .opt_bool = &print_help, .name = "help" },
+    { .opt_string = &notmuch_requested_db_uuid, .name = "uuid" },
+    { }
 };
 
 /* any subcommand wanting to support these options should call
@@ -82,8 +82,8 @@ int notmuch_minimal_options (const char *subcommand_name,
     int opt_index;
 
     notmuch_opt_desc_t options[] = {
-	{ NOTMUCH_OPT_INHERIT, (void *) &notmuch_shared_options, NULL, 0, 0 },
-	{ 0, 0, 0, 0, 0 }
+	{ .opt_inherit = notmuch_shared_options },
+	{ }
     };
 
     opt_index = parse_arguments (argc, argv, options, 1);
@@ -405,15 +405,15 @@ main (int argc, char *argv[])
     char *talloc_report;
     const char *command_name = NULL;
     command_t *command;
-    char *config_file_name = NULL;
+    const char *config_file_name = NULL;
     notmuch_config_t *config = NULL;
     int opt_index;
     int ret;
 
     notmuch_opt_desc_t options[] = {
-	{ NOTMUCH_OPT_STRING, &config_file_name, "config", 'c', 0 },
-	{ NOTMUCH_OPT_INHERIT, (void *) &notmuch_shared_options, NULL, 0, 0 },
-	{ 0, 0, 0, 0, 0 }
+	{ .opt_string = &config_file_name, .name = "config" },
+	{ .opt_inherit = notmuch_shared_options },
+	{ }
     };
 
     talloc_enable_null_tracking ();