balance_sheet: Support rewrite rules.

conservancy_beancount/reports/balance_sheet.py

@@ -50,6 +50,7 @@ import odf.table  # type:ignore[import]
 from beancount.parser import printer as bc_printer
 
 from . import core
+from . import rewrite
 from .. import books
 from .. import cliutil
 from .. import config as configmod
@@ -638,6 +639,15 @@ The default is one year ago.
         type=cliutil.date_arg,
         help="""Date to stop reporting entries, exclusive, in YYYY-MM-DD format.
 The default is a year after the start date.
+""")
+    parser.add_argument(
+        '--rewrite-rules', '--rewrites', '-r',
+        action='append',
+        default=[],
+        metavar='PATH',
+        type=Path,
+        help="""Use rewrite rules from the given YAML file. You can specify
+this option multiple times to load multiple sets of rewrite rules in order.
 """)
     parser.add_argument(
         '--fund-metadata-key', '-m',
@@ -695,8 +705,18 @@ def main(arglist: Optional[Sequence[str]]=None,
         bc_printer.print_error(error, file=stderr)
 
     data.Account.load_from_books(entries, options_map)
+    postings = data.Posting.from_entries(entries)
+    for rewrite_path in args.rewrite_rules:
+        try:
+            ruleset = rewrite.RewriteRuleset.from_yaml(rewrite_path)
+        except ValueError as error:
+            logger.critical("failed loading rewrite rules from %s: %s",
+                            rewrite_path, error.args[0])
+            return os.EX_DATAERR
+        postings = ruleset.rewrite(postings)
+
     balances = Balances(
-        data.Posting.from_entries(entries),
+        postings,
         args.start_date,
         args.stop_date,
         args.fund_metadata_key,