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, 8 insertions, 8 deletions

diff --git a/notmuch-count.c b/notmuch-count.c
index 97281374..b8b03cdb 100644
--- a/notmuch-count.c
+++ b/notmuch-count.c
@@ -166,24 +166,24 @@ notmuch_count_command (notmuch_config_t *config, int argc, char *argv[])
     notmuch_bool_t batch = FALSE;
     notmuch_bool_t print_lastmod = FALSE;
     FILE *input = stdin;
-    char *input_file_name = NULL;
+    const char *input_file_name = NULL;
     int ret;
 
     notmuch_opt_desc_t options[] = {
-	{ NOTMUCH_OPT_KEYWORD, &output, "output", 'o',
+	{ .opt_keyword = &output, .name = "output", .keywords =
 	  (notmuch_keyword_t []){ { "threads", OUTPUT_THREADS },
 				  { "messages", OUTPUT_MESSAGES },
 				  { "files", OUTPUT_FILES },
 				  { 0, 0 } } },
-	{ NOTMUCH_OPT_KEYWORD, &exclude, "exclude", 'x',
+	{ .opt_keyword = &exclude, .name = "exclude", .keywords =
 	  (notmuch_keyword_t []){ { "true", EXCLUDE_TRUE },
 				  { "false", EXCLUDE_FALSE },
 				  { 0, 0 } } },
-	{ NOTMUCH_OPT_BOOLEAN, &print_lastmod, "lastmod", 'l', 0 },
-	{ NOTMUCH_OPT_BOOLEAN, &batch, "batch", 0, 0 },
-	{ NOTMUCH_OPT_STRING, &input_file_name, "input", 'i', 0 },
-	{ NOTMUCH_OPT_INHERIT, (void *) &notmuch_shared_options, NULL, 0, 0 },
-	{ 0, 0, 0, 0, 0 }
+	{ .opt_bool = &print_lastmod, .name = "lastmod" },
+	{ .opt_bool = &batch, .name = "batch" },
+	{ .opt_string = &input_file_name, .name = "input" },
+	{ .opt_inherit = notmuch_shared_options },
+	{ }
     };
 
     opt_index = parse_arguments (argc, argv, options, 1);