Add package completion proof of concept (very bad)

pmb/helpers/other.py

@@ -24,6 +24,14 @@ import pmb.config
 import pmb.helpers.run
 
 
+def getpackagelist(aportsdir):
+    packages=set()
+    for dir in os.listdir(aportsdir):
+        for package in os.listdir('aports/'+dir):
+            packages.add(package)
+    return packages
+
+
 def folder_size(args, path):
     """
     Run `du` to calculate the size of a folder (this is less code and

pmb/parse/arguments.py

@@ -430,7 +430,7 @@ def arguments():
                        " is incompatible with how Alpine's abuild handles it.",
                        dest="ignore_depends")
     for action in [checksum, build, aportgen]:
-        action.add_argument("packages", nargs="+")
+        action.add_argument("packages", nargs="+", metavar="PACKAGES", choices=pmb.helpers.other.getpackagelist("aports"))
 
     # Action: kconfig_check / apkbuild_parse
     kconfig_check = sub.add_parser("kconfig_check", help="check, whether all"