libredbdiff: Add a helper for vercmp

I have a hard time reasoning about vercmp use in scripts, so add a
{{ A -lt B }} helper that works like [ A -lt B ], but for pacman versions.

1 files changed, 15 insertions, 5 deletions

diff --git a/src/abslibre-tools/libredbdiff b/src/abslibre-tools/libredbdiff
index 65ba4d6..bb6e068 100755
--- a/src/abslibre-tools/libredbdiff
+++ b/src/abslibre-tools/libredbdiff
@@ -60,16 +60,27 @@ createdir() {
 	fi
 }
 
+# {{ A -lt B }} is like [ A -lt B ], but for pacman version numbers
+{{() {
+	  [[ $# = 4 ]] || panic
+	  [[ $4 = '}}' ]] || panic
+	  local a=$1
+	  local op=$2
+	  local b=$3
+
+	  local cmp
+	  cmp="$(vercmp "$a" "$b")" || die "vercmp failed"
+	  [ "$cmp" "$op" 0 ]
+}
+
 # Globals:
 #  - pkgname  : the Parabola pkgname
 #  - ver_prbl : a map of pkgname->arch_pkgver
 #  - ver_arch : a map of pkgname->prbl_pkgver
 #  - provides : a map of pkgname->provides
 compare_pkgs() {
-	local cmp
 	if [[ -n "${ver_arch[$pkgname]}" ]] ; then
-		cmp=$(vercmp "${ver_prbl[$pkgname]}" "${ver_arch[$pkgname]}")
-		if [[ "$cmp" -lt 0 ]]; then
+		if {{ "${ver_prbl[$pkgname]}" -lt "${ver_arch[$pkgname]}" }}; then
 			printf "$printf_format" \
 				'=' \
 				"$pkgname" \
@@ -82,8 +93,7 @@ compare_pkgs() {
 		read -r -a _provides <<<"${provides[$pkgname]}"
 		for provide in "${_provides[@]}"; do
 			if [[ -n "${ver_arch[$provide]}" ]]; then
-				cmp=$(vercmp "${ver_prbl[$pkgname]}" "${ver_arch[$provide]}")
-				if [[ "$cmp" -lt 0 ]]; then
+				if {{ "${ver_prbl[$pkgname]}" -lt "${ver_arch[$provide]}" }}; then
 					printf "$printf_format" \
 						'p' \
 						"$pkgname" \