diff options
| -rw-r--r-- | Lib/string.py | 85 | ||||
| -rw-r--r-- | Lib/test/test_pep292.py | 114 |
2 files changed, 136 insertions, 63 deletions
diff --git a/Lib/string.py b/Lib/string.py index 9965111..fd9cc99 100644 --- a/Lib/string.py +++ b/Lib/string.py @@ -82,60 +82,83 @@ def maketrans(fromstr, tostr): #################################################################### import re as _re -class Template(unicode): +class _TemplateMetaclass(type): + pattern = r""" + (?P<escaped>%(delim)s{2}) | # Escape sequence of two delimiters + %(delim)s(?P<named>%(id)s) | # delimiter and a Python identifier + %(delim)s{(?P<braced>%(id)s)} | # delimiter and a braced identifier + (?P<bogus>%(delim)s) # 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' : cls.delimiter, + 'id' : cls.idpattern, + } + cls.pattern = _re.compile(pattern, _re.IGNORECASE | _re.VERBOSE) + + +class Template: """A string class for supporting $-substitutions.""" - __slots__ = [] + __metaclass__ = _TemplateMetaclass + + delimiter = r'\$' + idpattern = r'[_a-z][_a-z0-9]*' + + def __init__(self, template): + self.template = template # Search for $$, $identifier, ${identifier}, and any bare $'s - pattern = _re.compile(r""" - (?P<escaped>\${2})| # Escape sequence of two $ signs - \$(?P<named>[_a-z][_a-z0-9]*)| # $ and a Python identifier - \${(?P<braced>[_a-z][_a-z0-9]*)}| # $ and a brace delimited identifier - (?P<bogus>\$) # Other ill-formed $ expressions - """, _re.IGNORECASE | _re.VERBOSE) - - def __mod__(self, mapping): + + def _bogus(self, mo): + i = mo.start('bogus') + 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, mapping): def convert(mo): if mo.group('escaped') is not None: return '$' if mo.group('bogus') is not None: - raise ValueError('Invalid placeholder at index %d' % - mo.start('bogus')) + self._bogus(mo) val = mapping[mo.group('named') or mo.group('braced')] - return unicode(val) - return self.pattern.sub(convert, self) - - -class SafeTemplate(Template): - """A string class for supporting $-substitutions. - - This class is 'safe' in the sense that you will never get KeyErrors if - there are placeholders missing from the interpolation dictionary. In that - case, you will get the original placeholder in the value string. - """ - __slots__ = [] + # 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 __mod__(self, mapping): + def safe_substitute(self, mapping): def convert(mo): if mo.group('escaped') is not None: return '$' if mo.group('bogus') is not None: - raise ValueError('Invalid placeholder at index %d' % - mo.start('bogus')) + self._bogus(mo) named = mo.group('named') if named is not None: try: - return unicode(mapping[named]) + # 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 '$' + named braced = mo.group('braced') try: - return unicode(mapping[braced]) + return '%s' % mapping[braced] except KeyError: return '${' + braced + '}' - return self.pattern.sub(convert, self) + return self.pattern.sub(convert, self.template) -del _re #################################################################### diff --git a/Lib/test/test_pep292.py b/Lib/test/test_pep292.py index 7eff309..56eb417 100644 --- a/Lib/test/test_pep292.py +++ b/Lib/test/test_pep292.py @@ -3,70 +3,120 @@ # License: http://www.opensource.org/licenses/PythonSoftFoundation.php import unittest -from string import Template, SafeTemplate +from string import Template + + +class Bag: + pass + +class Mapping: + def __getitem__(self, name): + obj = self + for part in name.split('.'): + try: + obj = getattr(obj, part) + except AttributeError: + raise KeyError(name) + return obj -class TestTemplate(unittest.TestCase): +class TestTemplate(unittest.TestCase): def test_regular_templates(self): s = Template('$who likes to eat a bag of $what worth $$100') - self.assertEqual(s % dict(who='tim', what='ham'), + self.assertEqual(s.substitute(dict(who='tim', what='ham')), 'tim likes to eat a bag of ham worth $100') - self.assertRaises(KeyError, lambda s, d: s % d, s, dict(who='tim')) + self.assertRaises(KeyError, s.substitute, dict(who='tim')) def test_regular_templates_with_braces(self): s = Template('$who likes ${what} for ${meal}') - self.assertEqual(s % dict(who='tim', what='ham', meal='dinner'), - 'tim likes ham for dinner') - self.assertRaises(KeyError, lambda s, d: s % d, - s, dict(who='tim', what='ham')) + d = dict(who='tim', what='ham', meal='dinner') + self.assertEqual(s.substitute(d), 'tim likes ham for dinner') + self.assertRaises(KeyError, s.substitute, + dict(who='tim', what='ham')) def test_escapes(self): eq = self.assertEqual s = Template('$who likes to eat a bag of $$what worth $$100') - eq(s % dict(who='tim', what='ham'), + eq(s.substitute(dict(who='tim', what='ham')), 'tim likes to eat a bag of $what worth $100') s = Template('$who likes $$') - eq(s % dict(who='tim', what='ham'), 'tim likes $') + eq(s.substitute(dict(who='tim', what='ham')), 'tim likes $') def test_percents(self): + eq = self.assertEqual s = Template('%(foo)s $foo ${foo}') - self.assertEqual(s % dict(foo='baz'), '%(foo)s baz baz') - s = SafeTemplate('%(foo)s $foo ${foo}') - self.assertEqual(s % dict(foo='baz'), '%(foo)s baz baz') + d = dict(foo='baz') + eq(s.substitute(d), '%(foo)s baz baz') + eq(s.safe_substitute(d), '%(foo)s baz baz') def test_stringification(self): + eq = self.assertEqual s = Template('tim has eaten $count bags of ham today') - self.assertEqual(s % dict(count=7), - 'tim has eaten 7 bags of ham today') - s = SafeTemplate('tim has eaten $count bags of ham today') - self.assertEqual(s % dict(count=7), - 'tim has eaten 7 bags of ham today') - s = SafeTemplate('tim has eaten ${count} bags of ham today') - self.assertEqual(s % dict(count=7), - 'tim has eaten 7 bags of ham today') + d = dict(count=7) + eq(s.substitute(d), 'tim has eaten 7 bags of ham today') + eq(s.safe_substitute(d), 'tim has eaten 7 bags of ham today') + s = Template('tim has eaten ${count} bags of ham today') + eq(s.substitute(d), 'tim has eaten 7 bags of ham today') def test_SafeTemplate(self): eq = self.assertEqual - s = SafeTemplate('$who likes ${what} for ${meal}') - eq(s % dict(who='tim'), - 'tim likes ${what} for ${meal}') - eq(s % dict(what='ham'), - '$who likes ham for ${meal}') - eq(s % dict(what='ham', meal='dinner'), + s = Template('$who likes ${what} for ${meal}') + eq(s.safe_substitute(dict(who='tim')), 'tim likes ${what} for ${meal}') + eq(s.safe_substitute(dict(what='ham')), '$who likes ham for ${meal}') + eq(s.safe_substitute(dict(what='ham', meal='dinner')), '$who likes ham for dinner') - eq(s % dict(who='tim', what='ham'), + eq(s.safe_substitute(dict(who='tim', what='ham')), 'tim likes ham for ${meal}') - eq(s % dict(who='tim', what='ham', meal='dinner'), + eq(s.safe_substitute(dict(who='tim', what='ham', meal='dinner')), 'tim likes ham for dinner') def test_invalid_placeholders(self): raises = self.assertRaises s = Template('$who likes $') - raises(ValueError, lambda s, d: s % d, s, dict(who='tim')) + raises(ValueError, s.substitute, dict(who='tim')) s = Template('$who likes ${what)') - raises(ValueError, lambda s, d: s % d, s, dict(who='tim')) + raises(ValueError, s.substitute, dict(who='tim')) s = Template('$who likes $100') - raises(ValueError, lambda s, d: s % d, s, dict(who='tim')) + raises(ValueError, s.substitute, dict(who='tim')) + + def test_delimiter_override(self): + class PieDelims(Template): + delimiter = '@' + s = PieDelims('@who likes to eat a bag of @{what} worth $100') + self.assertEqual(s.substitute(dict(who='tim', what='ham')), + 'tim likes to eat a bag of ham worth $100') + + def test_idpattern_override(self): + class PathPattern(Template): + idpattern = r'[_a-z][._a-z0-9]*' + m = Mapping() + m.bag = Bag() + m.bag.foo = Bag() + m.bag.foo.who = 'tim' + m.bag.what = 'ham' + s = PathPattern('$bag.foo.who likes to eat a bag of $bag.what') + self.assertEqual(s.substitute(m), 'tim likes to eat a bag of ham') + + def test_pattern_override(self): + class MyPattern(Template): + pattern = r""" + (?P<escaped>@{2}) | + @(?P<named>[_a-z][._a-z0-9]*) | + @{(?P<braced>[_a-z][._a-z0-9]*)} | + (?P<bogus>@) + """ + m = Mapping() + m.bag = Bag() + m.bag.foo = Bag() + m.bag.foo.who = 'tim' + m.bag.what = 'ham' + s = MyPattern('@bag.foo.who likes to eat a bag of @bag.what') + self.assertEqual(s.substitute(m), 'tim likes to eat a bag of ham') + + def test_unicode_values(self): + s = Template('$who likes $what') + d = dict(who=u't\xffm', what=u'f\xfe\fed') + self.assertEqual(s.substitute(d), u't\xffm likes f\xfe\x0ced') def suite(): |