feat: add cli_print_options with extensible arg type system

example/main.c

@@ -16,17 +16,42 @@ struct greet_config {
 	uint8_t flags;
 };
 
+/* Forward declarations */
+static int handle_help(const char *arg, void *cfg);
+static int handle_version(const char *arg, void *cfg);
+static int handle_verbose(const char *arg, void *cfg);
+static int handle_name(const char *arg, void *cfg);
+static int handle_count(const char *arg, void *cfg);
+/* ------------------- */
+
+/* Option table */
+
+#define GREET_OPTIONS_LIST \
+	X('h', "help",    no_argument,       handle_help,    OPT_ARG_NONE,   "Display this help") \
+	X('V', "version", no_argument,       handle_version, OPT_ARG_NONE,   "Display version") \
+	X('v', "verbose", no_argument,       handle_verbose, OPT_ARG_NONE,   "Verbose output") \
+	X('n', "name",    required_argument, handle_name,    OPT_ARG_STRING, "Name to greet") \
+	X('c', "count",   required_argument, handle_count,   OPT_ARG_UINT,   "Number of greetings")
+
+#define X(s, l, a, h, t, d) + 1
+enum { GREET_NB_OPTS = 0 GREET_OPTIONS_LIST };
+#undef X
+
+#define X(s, l, a, h, t, d) + (1 + (a != no_argument ? 1 : 0))
+enum { GREET_OPTSTR_LEN = 1 GREET_OPTIONS_LIST };
+#undef X
+
+#define X(s, l, a, h, t, d) { s, l, a, h, t, d },
+static const struct option_descriptor g_opts[] = { GREET_OPTIONS_LIST };
+#undef X
+
 /* Handlers */
 
 static int
 handle_help(__unused const char *arg, __unused void *cfg)
 {
-	printf("Usage: greet [OPTIONS] ...\n\n");
+	printf("Usage: greet [OPTIONS]\n\n");
-	printf("  -h, --help          Display this help\n");
+	cli_print_options(g_opts, GREET_NB_OPTS, cli_arg_type_to_str);
-	printf("  -V, --version       Display version\n");
-	printf("  -v, --verbose       Verbose output\n");
-	printf("  -n, --name NAME     Name to greet (default: world)\n");
-	printf("  -c, --count N       Number of greetings (default: 1)\n");
 	return CLI_EXIT_SUCCESS;
 }
 
@@ -62,27 +87,6 @@ handle_count(const char *arg, void *cfg)
 	return CLI_SUCCESS;
 }
 
-/* Option table */
-
-#define GREET_OPTIONS_LIST \
-	X('h', "help", no_argument, handle_help, OPT_ARG_NONE, "Display this help") \
-	X('V', "version", no_argument, handle_version, OPT_ARG_NONE, "Display version") \
-	X('v', "verbose", no_argument, handle_verbose, OPT_ARG_NONE, "Verbose output") \
-	X('n', "name", required_argument, handle_name, OPT_ARG_STRING, "Name to greet") \
-	X('c', "count", required_argument, handle_count, OPT_ARG_UINT, "Number of greetings")
-
-#define X(s, l, a, h, t, d) + 1
-enum { GREET_NB_OPTS = 0 GREET_OPTIONS_LIST };
-#undef X
-
-#define X(s, l, a, h, t, d) + (1 + (a != no_argument ? 1 : 0))
-enum { GREET_OPTSTR_LEN = 1 GREET_OPTIONS_LIST };
-#undef X
-
-#define X(s, l, a, h, t, d) { s, l, a, h, t, d },
-static const struct option_descriptor g_opts[] = { GREET_OPTIONS_LIST };
-#undef X
-
 /* Main */
 
 int

include/cli.h

@@ -11,17 +11,7 @@ enum cli_code {
 };
 
 typedef int (*t_option_handler)(const char *arg, void *config);
-
+typedef const char *(*t_arg_type_to_str)(int type);
-enum option_arg_type
-{
-	OPT_ARG_NONE = 0,
-	OPT_ARG_INT,
-	OPT_ARG_UINT,
-	OPT_ARG_SECONDS,
-	OPT_ARG_BYTES,
-	OPT_ARG_TTL,
-	OPT_ARG_STRING
-};
 
 struct option_descriptor
 {
@@ -29,11 +19,27 @@ struct option_descriptor
 	const char *long_opt;
 	int has_arg;
 	t_option_handler handler;
-	enum option_arg_type arg_type;
+	int arg_type;
 	const char *description;
 };
 
+/* Default arg types — clients may define their own */
+#define CLI_OPT_ARG_TYPES \
+	X(OPT_ARG_NONE,   ""     ) \
+	X(OPT_ARG_INT,    "<NUM>") \
+	X(OPT_ARG_UINT,   "<NUM>") \
+	X(OPT_ARG_FLOAT,  "<NUM>") \
+	X(OPT_ARG_STRING, "<STR>")
+
+#define X(name, str) name,
+enum { CLI_OPT_ARG_TYPES };
+#undef X
+
 void cli_set_prog_name(const char *name);
+void cli_print_options(const struct option_descriptor *opts, size_t nb_opts,
+	t_arg_type_to_str to_str);
+
+const char *cli_arg_type_to_str(int type);
 
 enum cli_code cli_parse(int argc, char **argv, void *config,
 	const struct option_descriptor *opts, size_t nb_opts,

src/help.c

@@ -0,0 +1,34 @@
+#include <stdio.h>
+#include <stddef.h>
+
+#include "cli.h"
+#include "compiler.h"
+
+const char *
+cli_arg_type_to_str(int type)
+{
+	static const char *strs[] = {
+		#define X(name, str) str,
+		CLI_OPT_ARG_TYPES
+		#undef X
+	};
+	if ((size_t)type < COUNT_OF(strs))
+		return strs[type];
+	return "<ARG>";
+}
+
+void
+cli_print_options(const struct option_descriptor *opts, size_t nb_opts,
+	t_arg_type_to_str to_str)
+{
+	printf("Options:\n");
+	for (size_t i = 0; i < nb_opts; i++)
+	{
+		const char *argstr = to_str(opts[i].arg_type);
+		printf("  -%c, --%-15s %-8s %s\n",
+			opts[i].short_opt,
+			opts[i].long_opt,
+			argstr,
+			opts[i].description);
+	}
+}