134 lines
4.4 KiB
Python
134 lines
4.4 KiB
Python
#!/usr/bin/env python
|
|
# -*- coding: utf8 -*-
|
|
|
|
# string_template_compat.py: string.Template for Python <= 2.4
|
|
# =====================================================
|
|
|
|
# This is just an excerpt of the standard string module to provide backwards
|
|
# compatibility.
|
|
|
|
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"""
|
|
%(delim)s(?:
|
|
(?P<escaped>%(delim)s) | # Escape sequence of two delimiters
|
|
(?P<named>%(id)s) | # delimiter and a Python identifier
|
|
{(?P<braced>%(id)s)} | # delimiter and a braced identifier
|
|
(?P<invalid>) # Other ill-formed delimiter exprs
|
|
)
|
|
"""
|
|
|
|
def __init__(cls, name, bases, dct):
|
|
super(_TemplateMetaclass, cls).__init__(name, bases, dct)
|
|
if 'pattern' in dct:
|
|
pattern = cls.pattern
|
|
else:
|
|
pattern = _TemplateMetaclass.pattern % {
|
|
'delim' : _re.escape(cls.delimiter),
|
|
'id' : cls.idpattern,
|
|
}
|
|
cls.pattern = _re.compile(pattern, _re.IGNORECASE | _re.VERBOSE)
|
|
|
|
|
|
class Template:
|
|
"""A string class for supporting $-substitutions."""
|
|
__metaclass__ = _TemplateMetaclass
|
|
|
|
delimiter = '$'
|
|
idpattern = r'[_a-z][_a-z0-9]*'
|
|
|
|
def __init__(self, template):
|
|
self.template = template
|
|
|
|
# Search for $$, $identifier, ${identifier}, and any bare $'s
|
|
|
|
def _invalid(self, mo):
|
|
i = mo.start('invalid')
|
|
lines = self.template[:i].splitlines(True)
|
|
if not lines:
|
|
colno = 1
|
|
lineno = 1
|
|
else:
|
|
colno = i - len(''.join(lines[:-1]))
|
|
lineno = len(lines)
|
|
raise ValueError('Invalid placeholder in string: line %d, col %d' %
|
|
(lineno, colno))
|
|
|
|
def substitute(self, *args, **kws):
|
|
if len(args) > 1:
|
|
raise TypeError('Too many positional arguments')
|
|
if not args:
|
|
mapping = kws
|
|
elif kws:
|
|
mapping = _multimap(kws, args[0])
|
|
else:
|
|
mapping = args[0]
|
|
# Helper function for .sub()
|
|
def convert(mo):
|
|
# Check the most common path first.
|
|
named = mo.group('named') or mo.group('braced')
|
|
if named is not None:
|
|
val = mapping[named]
|
|
# We use this idiom instead of str() because the latter will
|
|
# fail if val is a Unicode containing non-ASCII characters.
|
|
return '%s' % (val,)
|
|
if mo.group('escaped') is not None:
|
|
return self.delimiter
|
|
if mo.group('invalid') is not None:
|
|
self._invalid(mo)
|
|
raise ValueError('Unrecognized named group in pattern',
|
|
self.pattern)
|
|
return self.pattern.sub(convert, self.template)
|
|
|
|
def safe_substitute(self, *args, **kws):
|
|
if len(args) > 1:
|
|
raise TypeError('Too many positional arguments')
|
|
if not args:
|
|
mapping = kws
|
|
elif kws:
|
|
mapping = _multimap(kws, args[0])
|
|
else:
|
|
mapping = args[0]
|
|
# Helper function for .sub()
|
|
def convert(mo):
|
|
named = mo.group('named')
|
|
if named is not None:
|
|
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],)
|
|
except KeyError:
|
|
return self.delimiter + named
|
|
braced = mo.group('braced')
|
|
if braced is not None:
|
|
try:
|
|
return '%s' % (mapping[braced],)
|
|
except KeyError:
|
|
return self.delimiter + '{' + braced + '}'
|
|
if mo.group('escaped') is not None:
|
|
return self.delimiter
|
|
if mo.group('invalid') is not None:
|
|
return self.delimiter
|
|
raise ValueError('Unrecognized named group in pattern',
|
|
self.pattern)
|
|
return self.pattern.sub(convert, self.template)
|
|
|