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# -*- coding: utf-8 -*-
#
# Copyright (C) 2007 Edgewall Software
# All rights reserved.
#
# This software is licensed as described in the file COPYING, which
# you should have received as part of this distribution. The terms
# are also available at http://babel.edgewall.org/wiki/License.
#
# This software consists of voluntary contributions made by many
# individuals. For the exact contribution history, see the revision
# history and logs, available at http://babel.edgewall.org/log/.
"""Various routines that help with validation of translations.
:since: version 0.9
"""
from itertools import izip
from babel.messages.catalog import TranslationError, PYTHON_FORMAT
from babel.util import set
#: list of format chars that are compatible to each other
_string_format_compatibilities = [
set(['i', 'd', 'u']),
set(['x', 'X']),
set(['f', 'F', 'g', 'G'])
]
def num_plurals(catalog, message):
"""Verify the number of plurals in the translation."""
if not message.pluralizable:
if not isinstance(message.string, basestring):
raise TranslationError("Found plural forms for non-pluralizable "
"message")
return
# skip further tests if no catalog is provided.
elif catalog is None:
return
msgstrs = message.string
if not isinstance(msgstrs, (list, tuple)):
msgstrs = (msgstrs,)
if len(msgstrs) != catalog.num_plurals:
raise TranslationError("Wrong number of plural forms (expected %d)" %
catalog.num_plurals)
def python_format(catalog, message):
"""Verify the format string placeholders in the translation."""
if 'python-format' not in message.flags:
return
msgids = message.id
if not isinstance(msgids, (list, tuple)):
msgids = (msgids,)
msgstrs = message.string
if not isinstance(msgstrs, (list, tuple)):
msgstrs = (msgstrs,)
for msgid, msgstr in izip(msgids, msgstrs):
if msgstr:
_validate_format(msgid, msgstr)
def _validate_format(format, alternative):
"""Test format string `alternative` against `format`. `format` can be the
msgid of a message and `alternative` one of the `msgstr`\s. The two
arguments are not interchangeable as `alternative` may contain less
placeholders if `format` uses named placeholders.
The behavior of this function is undefined if the string does not use
string formattings.
If the string formatting of `alternative` is compatible to `format` the
function returns `None`, otherwise a `TranslationError` is raised.
Examples for compatible format strings:
>>> _validate_format('Hello %s!', 'Hallo %s!')
>>> _validate_format('Hello %i!', 'Hallo %d!')
Example for an incompatible format strings:
>>> _validate_format('Hello %(name)s!', 'Hallo %s!')
Traceback (most recent call last):
...
TranslationError: the format strings are of different kinds
This function is used by the `python_format` checker.
:param format: The original format string
:param alternative: The alternative format string that should be checked
against format
:return: None on success
:raises TranslationError: on formatting errors
"""
def _parse(string):
result = []
for match in PYTHON_FORMAT.finditer(string):
name, format, typechar = match.groups()
if typechar == '%' and name is None:
continue
result.append((name, str(typechar)))
return result
def _compatible(a, b):
if a == b:
return True
for set in _string_format_compatibilities:
if a in set and b in set:
return True
return False
def _check_positional(results):
positional = None
for name, char in results:
if positional is None:
positional = name is None
else:
if (name is None) != positional:
raise TranslationError('format string mixes positional '
'and named placeholders')
return bool(positional)
a, b = map(_parse, (format, alternative))
# now check if both strings are positional or named
a_positional, b_positional = map(_check_positional, (a, b))
if a_positional and not b_positional and not b:
raise TranslationError('placeholders are incompatible')
elif a_positional != b_positional:
raise TranslationError('the format strings are of different kinds')
# if we are operating on positional strings both must have the
# same number of format chars and those must be compatible
if a_positional:
if len(a) != len(b):
raise TranslationError('positional format placeholders are '
'unbalanced')
for idx, ((_, first), (_, second)) in enumerate(izip(a, b)):
if not _compatible(first, second):
raise TranslationError('incompatible format for placeholder '
'%d: %r and %r are not compatible' %
(idx + 1, first, second))
# otherwise the second string must not have names the first one
# doesn't have and the types of those included must be compatible
else:
type_map = dict(a)
for name, typechar in b:
if name not in type_map:
raise TranslationError('unknown named placeholder %r' % name)
elif not _compatible(typechar, type_map[name]):
raise TranslationError('incompatible format for '
'placeholder %r: '
'%r and %r are not compatible' %
(name, typechar, type_map[name]))
def _find_checkers():
try:
from pkg_resources import working_set
except ImportError:
return [num_plurals, python_format]
checkers = []
for entry_point in working_set.iter_entry_points('babel.checkers'):
checkers.append(entry_point.load())
return checkers
checkers = _find_checkers()
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