Add support for subcommand names.

This should simplify using grecs in programs that implement a subcommand
notion (a la git or svn, e.g. myprod doit -n *).

* build-aux/getopt.m4 (STDFUNC): Initialize the subcmd member of
struct grecs_proginfo.
(OPTIONS_COMMAND_BEGIN): New macro.
* src/grecsopt.h (grecs_proginfo) <subcmd>: New member.
* src/opthelp.c (grecs_print_help): if defined, print the subcommand
and its aliases.

1 files changed, 26 insertions, 2 deletions

diff --git a/src/opthelp.c b/src/opthelp.c
index 58deeed..75e48d2 100644
--- a/src/opthelp.c
+++ b/src/opthelp.c
@@ -118,9 +118,20 @@ grecs_print_help(struct grecs_proginfo *pinfo)
 	struct grecs_opthelp *opthelp;
 	size_t optcount;
 
-	printf("%s %s [%s]... %s\n",
-	       _("Usage:"), pinfo->progname, _("OPTION"),
+	printf("%s %s ",
+	       _("Usage:"), pinfo->progname);
+	if (pinfo->subcmd)
+		printf("%s ", pinfo->subcmd[0]);
+	printf("[%s]... %s\n",
+	       _("OPTION"),
 	       !ISEMPTY(pinfo->args_doc) ? gettext(pinfo->args_doc) : "");
+	if (pinfo->subcmd && pinfo->subcmd[1]) {
+		const char **p;
+
+		printf("%s: ", pinfo->subcmd[2] ? _("Aliases") : _("Alias"));
+		for (p = pinfo->subcmd + 1; *p; p++)
+			printf("%s%c", *p, p[1] ? ' ' : '\n');
+	}
 	if (!ISEMPTY(pinfo->docstring))
 		print_option_descr(gettext(pinfo->docstring), 0, RMARGIN);
 	putchar('\n');
@@ -255,6 +266,8 @@ grecs_print_usage(struct grecs_proginfo *pinfo)
 	buf = grecs_malloc(bufsize);
 	
 	n = snprintf(buf, bufsize, "%s %s ", _("Usage:"), pinfo->progname);
+	if (pinfo->subcmd)
+		n += snprintf(buf + n, bufsize - n, "%s ", pinfo->subcmd[0]);
 	
 	/* Print a list of short options without arguments. */
 	for (i = nidx = 0; i < optcount; i++)
@@ -368,6 +381,17 @@ grecs_print_usage(struct grecs_proginfo *pinfo)
 	}
 #endif
 	FLUSH;
+
+	if (pinfo->subcmd && pinfo->subcmd[1]) {
+		const char **p;
+		
+		printf("%s: %s", pinfo->subcmd[2] ? _("Aliases") : _("Alias"),
+			pinfo->progname);
+		for (p = pinfo->subcmd + 1; *p; p++)
+			printf(" %s", *p);
+		putchar('\n');
+	}
+	
 	free(optidx);
 	free(buf);
 }