main: Improve readability of collect_predicates

Instead of adding another indentation level, exit early if a value or a
key can be ignored.

1 files changed, 19 insertions, 10 deletions

diff --git a/quarg/main.py b/quarg/main.py
index eeaf943..2973a2a 100644
--- a/quarg/main.py
+++ b/quarg/main.py
@@ -141,16 +141,25 @@ def collect_predicates(args):
     }
 
     for key, value in vars(args).items():
-        # FIXME sadly the 'joined' namespace will contain a falsy value, so
-        # check against None or []
-        if key in funs and value not in [None, []]:
-            fun = funs[key]
-            if args.debug:
-                print(f'{key}: {value}', file=sys.stderr)
-            if isinstance(value, list):
-                yield filters.any_filter(fun, value)
-            else:
-                yield fun(value)
+        # ignore unset or empty arguments
+        # Note: 'if not value' does not work here because 'joined' can be falsy
+        # but still needs to be passed to filters.joined
+        if value is None or value == []:
+            continue
+
+        # ignore arguments that do not map to predicates
+        if key not in funs:
+            continue
+
+        if args.debug:
+            print(f'{key}: {value}', file=sys.stderr)
+
+        fun = funs[key]
+
+        if isinstance(value, list):
+            yield filters.any_filter(fun, value)
+        else:
+            yield fun(value)
 
 def run_query(session, predicates):
     start = timer()