On Fri, Aug 19 2022, SZEDER Gábor wrote:
> +static enum parse_opt_result parse_subcommand(const char *arg,
> + const struct option *options)
> +{
> + for (; options->type != OPTION_END; options++)
> + if (options->type == OPTION_SUBCOMMAND &&
> + !strcmp(options->long_name, arg)) {
> + *(parse_opt_subcommand_fn **)options->value = options->subcommand_fn;
Nit: Maybe do the cast by assigning to an intermediate variable? Would
make this less dense, and since we already have {}-braces...
> + return PARSE_OPT_SUBCOMMAND;
> + }
> +
> + return PARSE_OPT_UNKNOWN;
> +}
> +
> static void check_typos(const char *arg, const struct option *options)
> {
> if (strlen(arg) < 3)
> @@ -442,6 +457,7 @@ static void check_typos(const char *arg, const struct option *options)
> static void parse_options_check(const struct option *opts)
> {
> char short_opts[128];
> + void *subcommand_value = NULL;
>
> memset(short_opts, '\0', sizeof(short_opts));
> for (; opts->type != OPTION_END; opts++) {
> @@ -489,6 +505,14 @@ static void parse_options_check(const struct option *opts)
> "Are you using parse_options_step() directly?\n"
> "That case is not supported yet.");
> break;
> + case OPTION_SUBCOMMAND:
> + if (!opts->value || !opts->subcommand_fn)
> + optbug(opts, "OPTION_SUBCOMMAND needs a value and a subcommand function");
Better split into two IMO:
if (!opts->value)
optbug(opts, "OPTION_SUBCOMMAND needs a value");
if (!opts->subcommand_fn)
optbug(opts, "OPTION_SUBCOMMAND needs a subcommand_fn");
Then if we have extra checks we don't need to keep adding to a dense ||
and amend an existing string.
> +static int has_subcommands(const struct option *options)
> +{
> + for (; options->type != OPTION_END; options++)
> + if (options->type == OPTION_SUBCOMMAND)
> + return 1;
> + return 0;
> +}
I wondered if parse_options_check() couldn't take a "int
*has_subcommands", since we already loop through the options to check it
as part of the checks there (but we'd need to re-arrange them).
Not for optimization, just wondering if it would make the code flow
clearer, maybe not.
> + if (ctx->has_subcommands) {
> + if (flags & PARSE_OPT_STOP_AT_NON_OPTION)
> + BUG("subcommands are incompatible with PARSE_OPT_STOP_AT_NON_OPTION");
> + if (!(flags & PARSE_OPT_SUBCOMMAND_OPTIONAL)) {
> + if (flags & PARSE_OPT_KEEP_UNKNOWN_OPT)
> + BUG("subcommands are incompatible with PARSE_OPT_KEEP_UNKNOWN_OPT unless in combination with PARSE_OPT_SUBCOMMAND_OPTIONAL");
> + if (flags & PARSE_OPT_KEEP_DASHDASH)
> + BUG("subcommands are incompatible with PARSE_OPT_KEEP_DASHDASH unless in combination with PARSE_OPT_SUBCOMMAND_OPTIONAL");
MM, very long lines. Maybe something like:
BUG("%s flag cannot be combined with %s, unless %s is also provided", ...);
> + }
> + }
> if ((flags & PARSE_OPT_KEEP_UNKNOWN_OPT) &&
> (flags & PARSE_OPT_STOP_AT_NON_OPTION) &&
> !(flags & PARSE_OPT_ONE_SHOT))
> @@ -589,6 +634,7 @@ static int show_gitcomp(const struct option *opts, int show_all)
> int nr_noopts = 0;
>
> for (; opts->type != OPTION_END; opts++) {
> + const char *prefix = "--";
Ah, here we have a prefix variable, but it's more of an "infix"... :)
> + return PARSE_OPT_DONE;
> + error(_("unknown subcommand: `%s'"), arg);
> + usage_with_options(usagestr, options);
ditto earlier patch comment about usage_msg_opt() (also applies below)
> + case PARSE_OPT_NON_OPTION:
> + /* Impossible. */
We could just skip this comment as...
> + BUG("parse_subcommand() cannot return these");
...this makes it clear.
> case PARSE_OPT_DONE:
> + if (ctx.has_subcommands &&
> + !(flags & PARSE_OPT_SUBCOMMAND_OPTIONAL)) {
> + error(_("need a subcommand"));
> + usage_with_options(usagestr, options);
ditto.
> +typedef int parse_opt_subcommand_fn(int argc, const char **argv,
> + const char *prefix);
We usually define function typedefs like:
typedef int (*parse_opt_subcommand_fn)(...);
But I see that...
> enum parse_opt_type type;
> @@ -145,6 +155,7 @@ struct option {
> intptr_t defval;
> parse_opt_ll_cb *ll_callback;
> intptr_t extra;
> + parse_opt_subcommand_fn *subcommand_fn;
You're doing this consistently with parse_opt_ll_cb etc., fair enough.
> +#define OPT_SUBCOMMAND_F(l, v, fn, f) { \
> + .type = OPTION_SUBCOMMAND, \
> + .long_name = (l), \
> + .value = (v), \
> + .flags = (f), \
Nice to see this form
> + .subcommand_fn = (fn) }
Almost all other such decls end with:
.foo = bar, \
}
I.e. we put the closing "}" at the start of the line.
> +#define OPT_SUBCOMMAND(l, v, fn) OPT_SUBCOMMAND_F((l), (v), (fn), 0)
I think this would be more readable as:
#define OPT_SUBCOMMAND(l, v, fn) \
OPT_SUBCOMMAND_F((l), (v), (fn), 0)
Which both aligns nicely, and isn't using a \t in the middle of the line
(which in any case we'll end up aligning with nothing else, as the names
are all different lengths, if other things continue using this pattern.
> enum parse_opt_flags flags;
> + unsigned has_subcommands;
Maybe make it: "unsigned has_subcommands:1"?
> + printf("fn: subcmd_one\n");
s/printf/puts/g here
> + print_args(argc, argv);
> + return 0;
> +}
> +
> +static int subcmd_two(int argc, const char **argv, const char *prefix)
> +{
> + printf("fn: subcmd_two\n");
ditto.
