diff options
Diffstat (limited to 'Lib/string.py')
| -rw-r--r-- | Lib/string.py | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/Lib/string.py b/Lib/string.py index 9b00a62e88..03179fbb44 100644 --- a/Lib/string.py +++ b/Lib/string.py @@ -202,6 +202,13 @@ class Formatter: def vformat(self, format_string, args, kwargs): used_args = set() + result = self._vformat(format_string, args, kwargs, used_args, 2) + self.check_unused_args(used_args, args, kwargs) + return result + + def _vformat(self, format_string, args, kwargs, used_args, recursion_depth): + if recursion_depth < 0: + raise ValueError('Max string recursion exceeded') result = [] for literal_text, field_name, format_spec, conversion in \ self.parse(format_string): @@ -223,10 +230,13 @@ class Formatter: # do any conversion on the resulting object obj = self.convert_field(obj, conversion) + # expand the format spec, if needed + format_spec = self._vformat(format_spec, args, kwargs, + used_args, recursion_depth-1) + # format the object and append to the result result.append(self.format_field(obj, format_spec)) - self.check_unused_args(used_args, args, kwargs) return ''.join(result) @@ -251,9 +261,9 @@ class Formatter: return repr(value) elif conversion == 's': return str(value) - else: - assert conversion is None + elif conversion is None: return value + raise ValueError("Unknown converion specifier {0!s}".format(conversion)) # returns an iterable that contains tuples of the form: |