libremessages:flag: Fix several things (also librexgettext)

 - Fix a bug where it panicked if given an odd number of sub-headings.
 - Document the the ability to include sub-headings.
 - Fix librexgettext's handling of it.  It only worked correctly for times
   when it was only called once in a program, or when it was only ever
   called with exactly one flag/description pair (and no headings).

1 files changed, 8 insertions, 4 deletions

diff --git a/src/lib/messages.sh b/src/lib/messages.sh
index 4b4897e..0125003 100644
--- a/src/lib/messages.sh
+++ b/src/lib/messages.sh
@@ -92,14 +92,15 @@ bullet() {
 	printf -- "$mesg" "$@" | fmt -u -w 71 | sed -e '1s/^/  - /' -e '2,$s/^/    /'
 }
 
-# Usage: flag FLAG DESCRIPTION [FLAG2 DESCRIPTION2...]
+# Usage: flag [FLAG DESCRIPTION|HEADING:]...
 #
 # Print a flag and description formatted for --help text.
 #
 #   ex: flag '-C <FILE>' 'Use this file instead of pacman.conf'
 #
-# The description is fed through gettext, the flag is not, so if part
-# of the flag needs to be translated, you must do that yourself:
+# The descriptions and headings are fed through gettext, the flags ar
+# not, so if part of a flag needs to be translated, you must do that
+# yourself:
 #
 #   ex: flag "-C <$(_ FILE)>" 'Use this file instead of pacman.conf'
 #
@@ -107,8 +108,10 @@ bullet() {
 # crazy-long, feel free, it is reflowed/wrapped the same way as prose
 # and bullet.  If you pass in multiple flag/description pairs at once,
 # the descriptions are all alligned together.
+#
+# A heading MUST end with a colon (':'), this is how it knows that it
+# is a heading.  Similarly, a flag MUST NOT end with a colon.
 flag() {
-	[[ $# == $(($#/2*2)) ]] || panic
 	local args=("$@")
 
 	declare -i flaglen=0
@@ -147,6 +150,7 @@ flag() {
 			printf -- ' %s\n' "$(_ "$1")"
 			shift
 		else
+			[[ $# -gt 1 ]] || panic
 			local flag=$1
 			local desc="$(_ "$(whitespace_collapse <<<"$2")")"
 			shift 2