reports: Improve formatting of non-currency commodities.

Introduce the get_commodity_format() function, which returns Babel's
usual format string for currencies, but returns a version of it
"merged" with the locale's currency unit pattern for other
commodities.

BaseODS then calls this function where needed to format amounts.

conservancy_beancount/reports/core.py

@@ -737,7 +737,7 @@ class BaseODS(BaseSpreadsheet[RT, ST], metaclass=abc.ABCMeta):
             root: odf.element.Element,
             locale: babel.core.Locale,
             code: str,
-            fmt_index: int,
+            amount: DecimalCompat=0,
             properties: Optional[odf.style.TextProperties]=None,
             *,
             fmt_key: Optional[str]=None,
@@ -746,11 +746,7 @@ class BaseODS(BaseSpreadsheet[RT, ST], metaclass=abc.ABCMeta):
         if fmt_key is None:
             fmt_key = self.currency_fmt_key
         pattern = locale.currency_formats[fmt_key]
-        fmts = pattern.pattern.split(';')
-        try:
-            fmt = fmts[fmt_index]
-        except IndexError:
-            fmt = fmts[0]
+        fmt = get_commodity_format(locale, code, amount, fmt_key)
         style = self.replace_child(
             root,
             odf.number.CurrencyStyle,
@@ -823,7 +819,7 @@ class BaseODS(BaseSpreadsheet[RT, ST], metaclass=abc.ABCMeta):
                 root, locale, code, 0, positive_properties, volatile=True,
             )
             curr_style = self._build_currency_style(
-                root, locale, code, 1, negative_properties,
+                root, locale, code, -1, negative_properties,
             )
             curr_style.addElement(odf.style.Map(
                 condition='value()>=0', applystylename=pos_style,
@@ -1133,9 +1129,9 @@ class BaseODS(BaseSpreadsheet[RT, ST], metaclass=abc.ABCMeta):
             )
             return self.currency_cell(amount, **attrs)
         else:
-            lines = [babel.numbers.format_currency(
-                number, currency, locale=self.locale, format_type=self.currency_fmt_key,
-            ) for number, currency in balance.values()]
+            lines = [babel.numbers.format_currency(number, currency, get_commodity_format(
+                self.locale, currency, None, self.currency_fmt_key,
+            )) for number, currency in balance.values()]
             attrs['stylename'] = self.merge_styles(
                 attrs.get('stylename'), self.style_endtext,
             )
@@ -1287,6 +1283,47 @@ def account_balances(
         MutableBalance(),
     ))
 
+def get_commodity_format(locale: babel.core.Locale,
+                         code: str,
+                         amount: Optional[DecimalCompat]=None,
+                         format_type: str='accounting',
+) -> str:
+    """Return a format string for a commodity
+
+    Typical use looks like::
+
+      number, code = post.units
+      fmt = get_commodity_format(locale, code)
+      units_s = babel.numbers.format_currency(number, code, fmt)
+
+    When the commodity code refers to a real currency, you get the same format
+    string provided by Babel.
+
+    For other commodities like stock, you get a format code built from the
+    locale's currency unit pattern.
+
+    If ``amount`` is defined, the format string will be specifically for that
+    number, whether positive or negative. Otherwise, the format string may
+    define both positive and negative formats.
+    """
+    fmt: str = locale.currency_formats[format_type].pattern
+    if amount is not None:
+        fmt, _, neg_fmt = fmt.partition(';')
+        if amount < 0 and neg_fmt:
+            fmt = neg_fmt
+    symbol = babel.numbers.get_currency_symbol(code, locale)
+    if symbol != code:
+        return fmt
+    else:
+        long_fmt: str = babel.numbers.get_currency_unit_pattern(code, locale=locale)
+        return re.sub(
+            r'[#0,.\s¤]+',
+            lambda match: long_fmt.format(
+                match.group(0).replace('¤', '').strip(), '¤¤',
+            ),
+            fmt,
+        )
+
 def normalize_amount_func(account_name: str) -> Callable[[T], T]:
     """Get a function to normalize amounts for reporting
 

setup.py

@@ -5,7 +5,7 @@ from setuptools import setup
 setup(
     name='conservancy_beancount',
     description="Plugin, library, and reports for reading Conservancy's books",
-    version='1.9.5',
+    version='1.9.6',
     author='Software Freedom Conservancy',
     author_email='info@sfconservancy.org',
     license='GNU AGPLv3+',

tests/test_reports_spreadsheet.py

@@ -549,9 +549,7 @@ def test_ods_writer_balance_cell_multi_currency(ods_writer):
     ]]
     balance = core.Balance(amounts)
     cell = ods_writer.balance_cell(balance)
-    assert cell.text == '\0'.join(babel.numbers.format_currency(
-        number, currency, locale=EN_US, format_type='accounting',
-    ) for number, currency in amounts)
+    assert cell.text == '2,500.00 RUB\0R$3,500.00'
 
 @pytest.mark.parametrize('cell_source,style_name', testutil.combine_values(
     CURRENCY_CELL_DATA,