kiss-new: Argument handling

kiss-new

@@ -10,6 +10,9 @@
 # Keep in mind that this involves extra code in the case where
 # an error is optional or required.
 #
+# Where possible the package manager should "error first".
+# Check things first, die is necessary and continue if all is well.
+#
 # The code below conforms to shellcheck's rules. However, some
 # lint errors *are* disabled as they relate to unexpected
 # behavior (which we do expect).
@@ -56,10 +59,74 @@ pkg_search() {
     printf '%s\n' "$2"
 }
 
+pkg_list() {
+    # List installed packages. As the format is files and
+    # diectories, this just involves a simple for loop and
+    # file read.
+
+    # Changing directories is similar to storing the full
+    # full path in a variable, only there is no variable as
+    # you can access children relatively.
+    cd "$KISS_ROOT/var/db/kiss" || \
+        die "KISS database doesn't exist or is inaccessible."
+
+    # Optional arguments can be passed to check for specific
+    # packages. If no arguments are passed, list all. As we
+    # loop over '$@', if there aren't any arguments we can
+    # just set the directory contents to the argument list.
+    [ "$1" ] || set -- *
+
+    # Loop over each version file and warn if one doesn't exist.
+    # Supress errors from 'read' as we print our own message.
+    for pkg; do
+        [ -d "$pkg" ] || {
+            log "Package '$pkg' is not installed."
+            return 1
+        }
+
+        [ -f "$pkg/version" ] || {
+            log "Warning: Package '$pkg' has no version file."
+            return
+        }
+
+        read -r version release < "$pkg/version" &&
+            printf '%s\n' "${pkg%/*} $version-$release"
+    done
+}
+
 args() {
     # Parse script arguments manually. POSIX 'sh' has no 'getopts'
-    # or equivalent built in.
-    [ "$1" ] || {
+    # or equivalent built in. This is rather easy to do in our case
+    # since the first argument is always an "action" and the arguments
+    # that follow are all package names.
+
+    # Actions can be abbreviated to their first letter. This saves
+    # keystrokes once you memorize themand it also has the side-effect
+    # of "correcting" spelling mistakes assuming the first letter is
+    # right.
+    while [ "$1" ]; do
+        case $1 in
+            # Build the list of packages.
+            b*)
+
+            ;;
+
+            # List installed packages.
+            l*)
+                shift
+                pkg_list "$@"
+                exit
+            ;;
+
+            # Print version and exit.
+            v*)
+                log "$kiss 0.1.10"
+                exit
+            ;;
+
+            # Catch all invalid arguments as well as
+            # any help related flags (-h, --help, help).
+            *)
                 log "$kiss [b|c|i|l|r|u] [pkg]" \
                     "build:     Build a package." \
                     "checksum:  Generate checksums." \
@@ -68,16 +135,6 @@ args() {
                     "remove:    Remove a package." \
                     "update:    Check for updates."
                 exit
-    }
-
-    action=$1
-    shift
-
-    while [ "$1" ]; do
-        case $action in
-            b*)
-                pkg_search "$1"
-                shift
             ;;
         esac
     done