AxlArgs -- Argument Parser
==========================

Declarative command-line argument parser. Supports short flags (``-v``),
long flags (``--verbose``), value options (``-o file``, ``--port=8080``),
repeated options (``-H hdr1 -H hdr2``), and positional arguments.
``--`` stops option parsing.

Header: ``<axl/axl-args.h>``

Overview
--------

Define an option table, call ``axl_args_parse``, then query results:

.. code-block:: c

   #include <axl.h>

   static const AxlOpt opts[] = {
       { 'v', "--verbose", AXL_OPT_FLAG,  NULL,   "Verbose output" },
       { 'o', "--output",  AXL_OPT_VALUE, "FILE", "Output file" },
       { 'H', NULL,        AXL_OPT_MULTI, "HDR",  "HTTP header (repeatable)" },
       { 'h', "--help",    AXL_OPT_FLAG,  NULL,   "Show help" },
       { 0 }  // terminator
   };

   int main(int argc, char **argv) {
       AXL_AUTOPTR(AxlArgs) args = axl_args_parse(argc, argv, opts);
       if (args == NULL) {
           axl_args_usage("myapp", "[options] <file>", opts);
           return 1;
       }

       if (axl_args_flag(args, 'h')) {
           axl_args_usage("myapp", "[options] <file>", opts);
           return 0;
       }

       bool verbose = axl_args_flag(args, 'v');
       const char *output = axl_args_value(args, 'o');  // NULL if not given
       const char *file = axl_args_pos(args, 0);        // first positional

       // Repeated options
       size_t hdr_count = axl_args_multi_count(args, 'H');
       for (size_t i = 0; i < hdr_count; i++) {
           axl_printf("Header: %s\n", axl_args_multi(args, 'H', i));
       }

       return 0;
   }

Option Types
~~~~~~~~~~~~

============== =============================================
Type           Description
============== =============================================
AXL_OPT_FLAG   Boolean flag (``-v``, ``--verbose``)
AXL_OPT_VALUE  Takes a value (``-o file``, ``--port=8080``)
AXL_OPT_MULTI  Repeatable value (``-H hdr1 -H hdr2``)
============== =============================================

API Reference
-------------

.. doxygenfile:: axl-args.h