Re: [RFC] Re: Convert 'git blame' to parse_options()

On Mon, Jun 23, 2008 at 07:16:17PM +0000, Linus Torvalds wrote:

  Let's see if I can catch it elegantly.

  Following is a series split into incremental patches to migrate the
parse_options API to an incremental one. Only the last step provides a
functional incremental API.

  With that, you write parsers this way:

{
    struct parse_opt_ctx_t ctx;

    parse_options_start(&ctx, argc, argv, 0);

    for (;;) {
        const char *arg;

        switch (parse_options_step(&ctx, options, usagestr)) {
        case PARSE_OPT_HELP:
            /* dump your help here, the one for options/usagestr is already dumped */
            exit(129);
        case PARSE_OPT_DONE:
            goto done;
        }

        arg = *ctx->argv++;
        ctx->argc--;

        if (strcmp(arg, "-")) {
            /* you're on baby ! */
        } else if ....
        } else {
            error("unknown option %s", arg);
            parse_options_usage(options, usagestr);
            /* dump your help here */
            exit(129);
        }
    }

done:
    argc = parse_options_end(&ctx);
}

It's slightly more involved than what Linus handwaved, but I believe it's usable this way.