cliutil: Add ExtendAction.

This is a user affordance we've wanted for a while, and
query-report *really* wants it.

conservancy_beancount/cliutil.py

@@ -46,6 +46,7 @@ from typing import (
     IO,
     Iterable,
     Iterator,
+    List,
     NamedTuple,
     NoReturn,
     Optional,
@@ -195,6 +196,42 @@ class ExitCode(enum.IntEnum):
     BeancountErrors = 63
 
 
+class ExtendAction(argparse.Action):
+    """argparse action to let a user build a list from a string
+
+    This is a fancier version of argparse's built-in ``action='append'``.
+    The user's input is turned into a list of strings, split by a regexp
+    pattern you provide. Typical usage looks like::
+
+        parser = argparse.ArgumentParser()
+        parser.add_argument(
+          '--option', ...,
+          action=ExtendAction,
+          const=regexp_pattern,  # default is r'\s*,\s*'
+          ...,
+        )
+    """
+    DEFAULT_PATTERN = r'\s*,\s*'
+
+    def __call__(self,
+                 parser: argparse.ArgumentParser,
+                 namespace: argparse.Namespace,
+                 values: Union[Sequence[Any], str, None]=None,
+                 option_string: Optional[str]=None,
+    ) -> None:
+        pattern: str = self.const or self.DEFAULT_PATTERN
+        value: Optional[List[str]] = getattr(namespace, self.dest, None)
+        if value is None:
+            value = []
+            setattr(namespace, self.dest, value)
+        if values is None:
+            values = []
+        elif isinstance(values, str):
+            values = [values]
+        for s in values:
+            value.extend(re.split(pattern, s))
+
+
 class InfoAction(argparse.Action):
     def __call__(self,
                  parser: argparse.ArgumentParser,

conservancy_beancount/reconcile/statement.py

@@ -338,10 +338,10 @@ The default is one month after the start date.
         '--account', '-a',
         dest='accounts',
         metavar='ACCOUNT',
-        action='append',
-        help="""Reconcile this account. You can specify this option
-multiple times. You can specify a part of the account hierarchy, or an account
-classification from metadata. Default adapts to your search criteria.
+        action=cliutil.ExtendAction,
+        help="""Reconcile this account. You can specify multiple
+comma-separated accounts or classifications, and/or specify this option
+multiple times. Default adapts to your search criteria.
 """)
     parser.add_argument(
         '--id-metadata-key', '-i',

conservancy_beancount/reports/ledger.py

@@ -739,8 +739,9 @@ date was also not specified.
         '--account', '-a',
         dest='accounts',
         metavar='ACCOUNT',
-        action='append',
-        help="""Show this account in the report. You can specify this option
+        action=cliutil.ExtendAction,
+        help="""Show this account in the report. You can specify multiple
+comma-separated accounts or classifications, and/or specify this option
 multiple times. You can specify a part of the account hierarchy, or an account
 classification from metadata. If not specified, the default set adapts to your
 search criteria.
@@ -749,19 +750,21 @@ search criteria.
     parser.add_argument(
         '--show-totals', '-S',
         metavar='ACCOUNT',
-        action='append',
+        action=cliutil.ExtendAction,
         help="""When entries for this account appear in the report, include
-account balance(s) as well. You can specify this option multiple times. Pass in
-a part of the account hierarchy. The default is all accounts.
+account balance(s) as well. You can specify multiple comma-separated parts of
+the account hierarchy, and/or specify this option multiple times.
+The default is all accounts.
 """)
     parser.add_argument(
         '--add-totals', '-T',
         metavar='ACCOUNT',
-        action='append',
+        action=cliutil.ExtendAction,
         help="""When an account could be included in the report but does not
 have any entries in the date range, include a header and account balance(s) for
-it. You can specify this option multiple times. Pass in a part of the account
-hierarchy. The default set adapts to your search criteria.
+it. You can specify multiple comma-separated parts of the account hierarchy,
+and/or specify this option multiple times. The default set adapts to your
+search criteria.
 """)
     parser.add_argument(
         '--sheet-size', '--size',

tests/test_cliutil.py

@@ -298,3 +298,36 @@ def test_enum_arg_choices_str_defaults(arg_enum):
 def test_enum_arg_choices_str_args(arg_enum):
     sep = '/'
     assert arg_enum.choices_str(sep, '{}') == sep.join(c.value for c in ArgChoices)
+
+@pytest.mark.parametrize('values,sep', testutil.combine_values(
+    [['foo'], ['bar', 'baz'], ['qu', 'quu', 'quux']],
+    [',', ', ', '  ,', ' ,  '],
+))
+def test_extend_action_once(values, sep):
+    action = cliutil.ExtendAction(['-t'], 'result')
+    args = argparse.Namespace()
+    action(None, args, sep.join(values), '-t')
+    assert args.result == values
+
+def test_extend_action_multi():
+    action = cliutil.ExtendAction(['-t'], 'result')
+    args = argparse.Namespace()
+    action(None, args, 'foo,bar', '-t')
+    action(None, args, 'baz, quux', '-t')
+    assert args.result == ['foo', 'bar', 'baz', 'quux']
+
+def test_extend_action_from_default():
+    action = cliutil.ExtendAction(['-t'], 'result')
+    args = argparse.Namespace(result=['foo'])
+    action(None, args, 'bar , baz', '-t')
+    assert args.result == ['foo', 'bar', 'baz']
+
+@pytest.mark.parametrize('pattern,expected', [
+    (',', ['foo', ' bar']),
+    (r'\s+', ['foo,', 'bar']),
+])
+def test_extend_action_custom_pattern(pattern, expected):
+    action = cliutil.ExtendAction(['-t'], 'result', const=pattern)
+    args = argparse.Namespace()
+    action(None, args, 'foo, bar', '-t')
+    assert args.result == expected