Simplified tuple returned by string._formatter_parser to only have
4 elements. No need for old is_markup element, the same information
is indicated by literal_string being None.
Factored string.Formatter class to make subclasses easier to write.
diff --git a/Lib/string.py b/Lib/string.py
index 0663f31..cef5029 100644
--- a/Lib/string.py
+++ b/Lib/string.py
@@ -208,49 +208,83 @@
return self.vformat(format_string, args, kwargs)
def vformat(self, format_string, args, kwargs):
- used_args = set()
+ used_args = self.get_empty_used_args()
result = []
- for (is_markup, literal, field_name, format_spec, conversion) in \
- format_string._formatter_parser():
- if is_markup:
+ for literal_text, field_name, format_spec, conversion in \
+ self.parse(format_string):
+ if literal_text is None:
+ # this is some markup, find the object and do
+ # the formatting
+
# given the field_name, find the object it references
-
- # split it into the first part, and and iterator that
- # looks over the rest
- first, rest = field_name._formatter_field_name_split()
-
- used_args.add(first)
- obj = self.get_value(first, args, kwargs)
-
- # loop through the rest of the field_name, doing
- # getattr or getitem as needed
- for is_attr, i in rest:
- if is_attr:
- obj = getattr(obj, i)
- else:
- obj = obj[i]
+ obj = self.get_field(field_name, args, kwargs, used_args)
# do any conversion on the resulting object
- if conversion == 'r':
- obj = repr(obj)
- elif conversion == 's':
- obj = str(obj)
+ obj = self.convert_field(obj, conversion)
# format the object and append to the result
result.append(self.format_field(obj, format_spec))
else:
- result.append(literal)
+ # this is literal text, use it directly
+ result.append(literal_text)
self.check_unused_args(used_args, args, kwargs)
return ''.join(result)
+
+ def get_empty_used_args(self):
+ return set()
+
+
def get_value(self, key, args, kwargs):
if isinstance(key, int):
return args[key]
else:
return kwargs[key]
+
def check_unused_args(self, used_args, args, kwargs):
pass
+
def format_field(self, value, format_spec):
return format(value, format_spec)
+
+
+ def convert_field(self, value, conversion):
+ # do any conversion on the resulting object
+ if conversion == 'r':
+ return repr(value)
+ elif conversion == 's':
+ return str(value)
+ else:
+ assert conversion is None
+ return value
+
+
+ # returns an iterable that contains tuples of the form:
+ # (literal_text, field_name, format_spec, conversion)
+ def parse(self, format_string):
+ return format_string._formatter_parser()
+
+
+ # given a field_name, find the object it references.
+ # field_name: the field being looked up, e.g. "0.name"
+ # or "lookup[3]"
+ # used_args: a set of which args have been used
+ # args, kwargs: as passed in to vformat
+ # also, mark it as used in 'used_args'
+ def get_field(self, field_name, args, kwargs, used_args):
+ first, rest = field_name._formatter_field_name_split()
+
+ used_args.add(first)
+ obj = self.get_value(first, args, kwargs)
+
+ # loop through the rest of the field_name, doing
+ # getattr or getitem as needed
+ for is_attr, i in rest:
+ if is_attr:
+ obj = getattr(obj, i)
+ else:
+ obj = obj[i]
+
+ return obj