| 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657 |
- u"""
- Base classes for features that are backwards-incompatible.
- Usage:
- features = Features()
- features.add(Feature("py3k_feature", "power< 'py3k' any* >", "2.7"))
- PATTERN = features.PATTERN
- """
- pattern_unformatted = u"%s=%s" # name=pattern, for dict lookups
- message_unformatted = u"""
- %s is only supported in Python %s and above."""
- class Feature(object):
- u"""
- A feature has a name, a pattern, and a minimum version of Python 2.x
- required to use the feature (or 3.x if there is no backwards-compatible
- version of 2.x)
- """
- def __init__(self, name, PATTERN, version):
- self.name = name
- self._pattern = PATTERN
- self.version = version
- def message_text(self):
- u"""
- Format the above text with the name and minimum version required.
- """
- return message_unformatted % (self.name, self.version)
- class Features(set):
- u"""
- A set of features that generates a pattern for the features it contains.
- This set will act like a mapping in that we map names to patterns.
- """
- mapping = {}
- def update_mapping(self):
- u"""
- Called every time we care about the mapping of names to features.
- """
- self.mapping = dict([(f.name, f) for f in iter(self)])
- @property
- def PATTERN(self):
- u"""
- Uses the mapping of names to features to return a PATTERN suitable
- for using the lib2to3 patcomp.
- """
- self.update_mapping()
- return u" |\n".join([pattern_unformatted % (f.name, f._pattern) for f in iter(self)])
- def __getitem__(self, key):
- u"""
- Implement a simple mapping to get patterns from names.
- """
- return self.mapping[key]
|
