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Accepted Raymond's patch to combine mapping and keyword arguments, with slight

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modification.  Also, renamed the positional argument to '__mapping' to further
reduce the chance of duplicate keyword arguments.
This commit is contained in:
Barry Warsaw 2004-09-13 14:35:04 +00:00
parent 5011d0c683
commit 46b629c101
1 changed files with 32 additions and 5 deletions
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37
Lib/string.py
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@ -82,6 +82,23 @@ def maketrans(fromstr, tostr):
####################################################################
import re as _re
class _multimap:
"""Helper class for combining multiple mappings.
Used by .{safe_,}substitute() to combine the mapping and keyword
arguments.
"""
def __init__(self, primary, secondary):
self._primary = primary
self._secondary = secondary
def __getitem__(self, key):
try:
return self._primary[key]
except KeyError:
return self._secondary[key]
class _TemplateMetaclass(type):
pattern = r"""
(?P<escaped>%(delim)s{2}) | # Escape sequence of two delimiters
@ -126,19 +143,29 @@ def _bogus(self, mo):
raise ValueError('Invalid placeholder in string: line %d, col %d' %
(lineno, colno))
def substitute(self, mapping):
def substitute(self, __mapping=None, **kws):
if __mapping is None:
__mapping = kws
elif kws:
__mapping = _multimap(kws, __mapping)
# Helper function for .sub()
def convert(mo):
if mo.group('escaped') is not None:
return '$'
if mo.group('bogus') is not None:
self._bogus(mo)
val = mapping[mo.group('named') or mo.group('braced')]
val = __mapping[mo.group('named') or mo.group('braced')]
# We use this idiom instead of str() because the latter will fail
# if val is a Unicode containing non-ASCII characters.
return '%s' % val
return self.pattern.sub(convert, self.template)
def safe_substitute(self, mapping):
def safe_substitute(self, __mapping=None, **kws):
if __mapping is None:
__mapping = kws
elif kws:
__mapping = _multimap(kws, __mapping)
# Helper function for .sub()
def convert(mo):
if mo.group('escaped') is not None:
return '$'
@ -149,12 +176,12 @@ def convert(mo):
try:
# We use this idiom instead of str() because the latter
# will fail if val is a Unicode containing non-ASCII
return '%s' % mapping[named]
return '%s' % __mapping[named]
except KeyError:
return '$' + named
braced = mo.group('braced')
try:
return '%s' % mapping[braced]
return '%s' % __mapping[braced]
except KeyError:
return '${' + braced + '}'
return self.pattern.sub(convert, self.template)