bugfix: reserved constants (GOOD, BAD) as argument to flagGeneric

        failed, as they were evaluated during 'compile' time instead
        of execution time

saqc/core/visitor.py

@@ -160,7 +160,8 @@ class ConfigFunctionParser(ast.NodeVisitor):
         k, v = node.arg, node.value
         check_tree = True
 
-        # NOTE: not a constant or variable, should be function call
+        # NOTE: `node` is not a constant or a variable,
+        #       so it should be a function call
         try:
             visitor = ConfigExpressionParser(v)
             args = ast.arguments(
@@ -189,9 +190,16 @@ class ConfigFunctionParser(ast.NodeVisitor):
         # -> after all keywords where visited we end up with
         #    a dictionary holding all the passed arguments as
         #    real python objects
-        co = compile(ast.fix_missing_locations(ast.Interactive(body=[vnode])), "<ast>", mode="single")
-        # NOTE: only pass a copy to not clutter the ENVIRONMENT
-        exec(co, {**ENVIRONMENT}, self.kwargs)
+        if isinstance(v, ast.Name) and v.id in RESERVED:
+            # NOTE:
+            # the reserved constants needs to be evaluated during
+            # execution time, so dump the keyword directly and
+            # skip any further checks
+            self.kwargs[k] = v
+        else:
+            co = compile(ast.fix_missing_locations(ast.Interactive(body=[vnode])), "<ast>", mode="single")
+            # NOTE: only pass a copy to not clutter the ENVIRONMENT
+            exec(co, {**ENVIRONMENT}, self.kwargs)
 
         # let's do some more validity checks
         if check_tree:

test/funcs/test_generic_config_functions.py

@@ -216,14 +216,14 @@ def test_isflagged(data, flagger):
 
     tests = [
         (f"isflagged({var1})", flagger.isFlagged(var1)),
-        (f"isflagged({var1}, BAD)", flagger.isFlagged(var1, flag=flagger.BAD, comparator=">=")),
+        (f"isflagged({var1}, flag=BAD)", flagger.isFlagged(var1, flag=flagger.BAD, comparator=">=")),
         (f"isflagged({var1}, UNFLAGGED, '==')", flagger.isFlagged(var1, flag=flagger.UNFLAGGED, comparator="==")),
         (f"~isflagged({var2})", ~flagger.isFlagged(var2)),
         (f"~({var2}>999) & (~isflagged({var2}))", ~(data[var2] > 999) & (~flagger.isFlagged(var2))),
     ]
 
     for test, expected in tests:
-        func = _compileGeneric(f"flagGeneric(func={test})")
+        func = _compileGeneric(f"flagGeneric(func={test}, flag=BAD)")
         result = _execGeneric(flagger, data, func, field=None, nodata=np.nan)
         assert np.all(result == expected)