[Checkins] SVN: megrok.chameleon/branches/ulif-z3c.pt-less/src/megrok/chameleon/expressions.py Copy over expression translators from z3c.pt
Uli Fouquet
uli at gnufix.de
Mon Mar 1 19:54:03 EST 2010
Log message for revision 109546:
Copy over expression translators from z3c.pt
Changed:
A megrok.chameleon/branches/ulif-z3c.pt-less/src/megrok/chameleon/expressions.py
-=-
Copied: megrok.chameleon/branches/ulif-z3c.pt-less/src/megrok/chameleon/expressions.py (from rev 109545, z3c.pt/trunk/src/z3c/pt/expressions.py)
===================================================================
--- megrok.chameleon/branches/ulif-z3c.pt-less/src/megrok/chameleon/expressions.py (rev 0)
+++ megrok.chameleon/branches/ulif-z3c.pt-less/src/megrok/chameleon/expressions.py 2010-03-02 00:54:03 UTC (rev 109546)
@@ -0,0 +1,291 @@
+import re
+import namespaces
+import zope.event
+
+from zope.traversing.adapters import traversePathElement
+from zope.contentprovider.interfaces import IContentProvider
+from zope.contentprovider.interfaces import ContentProviderLookupError
+from zope.traversing.interfaces import ITraversable
+
+try:
+ from zope.contentprovider.interfaces import BeforeUpdateEvent
+except ImportError:
+ BeforeUpdateEvent = None
+
+from chameleon.core import types
+from chameleon.zpt import expressions
+from chameleon.zpt.interfaces import IExpressionTranslator
+
+from types import MethodType
+
+_marker = object()
+_valid_name = re.compile(r"[a-zA-Z][a-zA-Z0-9_]*$").match
+
+def identity(x):
+ return x
+
+class ContentProviderTraverser(object):
+ def __call__(self, context, request, view, name):
+ cp = zope.component.queryMultiAdapter(
+ (context, request, view), IContentProvider, name=name)
+
+ # provide a useful error message, if the provider was not found.
+ if cp is None:
+ raise ContentProviderLookupError(name)
+
+ if BeforeUpdateEvent is not None:
+ zope.event.notify(BeforeUpdateEvent(cp, request))
+ cp.update()
+ return cp.render()
+
+class ZopeTraverser(object):
+ def __init__(self, proxify=identity):
+ self.proxify = proxify
+
+ def __call__(self, base, request, call, *path_items):
+ """See ``zope.app.pagetemplate.engine``."""
+
+ if bool(path_items):
+ path_items = list(path_items)
+ path_items.reverse()
+
+ while len(path_items):
+ name = path_items.pop()
+ ns = ':' in name
+ if ns is True:
+ namespace, name = name.split(':', 1)
+ base = namespaces.function_namespaces[namespace](base)
+ if ITraversable.providedBy(base):
+ base = self.proxify(traversePathElement(
+ base, name, path_items, request=request))
+ continue
+
+ # special-case dicts for performance reasons
+ if isinstance(base, dict):
+ next = base.get(name, _marker)
+ else:
+ next = getattr(base, name, _marker)
+
+ if next is not _marker:
+ base = next
+ if ns is True and isinstance(base, MethodType):
+ base = base()
+ continue
+ else:
+ base = traversePathElement(
+ base, name, path_items, request=request)
+
+ if not isinstance(base, (basestring, tuple, list)):
+ base = self.proxify(base)
+
+ if call and getattr(base, '__call__', _marker) is not _marker:
+ return base()
+
+ return base
+
+class ZopeExistsTraverser(ZopeTraverser):
+ exceptions = AttributeError, LookupError, TypeError
+
+ def __call__(self, base, request, call, *args, **kwargs):
+ try:
+ return ZopeTraverser.__call__(
+ self, base, request, False, *args, **kwargs) is not None
+ except self.exceptions:
+ return False
+ return True
+
+class PathTranslator(expressions.ExpressionTranslator):
+ path_regex = re.compile(
+ r'^((nocall|not):\s*)*([A-Za-z_][A-Za-z0-9_:]*)'+
+ r'(/[?A-Za-z_@\-+][?A-Za-z0-9_@\-\.+/:]*)*$')
+
+ interpolation_regex = re.compile(
+ r'\?[A-Za-z][A-Za-z0-9_]+')
+
+ path_traverse = ZopeTraverser()
+ scope = 'request'
+
+ symbol = '_path'
+
+ def translate(self, string, escape=None):
+ """
+ >>> translate = PathTranslator().translate
+
+ >>> translate("") is None
+ True
+
+ >>> translate("nocall: a")
+ value('a')
+
+ >>> translate("nothing")
+ value('None')
+
+ >>> translate("a/b")
+ value("_path(a, request, True, 'b')")
+
+ Verify allowed character set.
+
+ >>> translate("image_path/++res++/@@hello.html")
+ value("_path(image_path, request, True, '++res++', '@@hello.html')")
+
+ >>> translate("context/@@view")
+ value("_path(context, request, True, '@@view')")
+
+ >>> translate("nocall: context/@@view")
+ value("_path(context, request, False, '@@view')")
+
+ >>> translate("context/?view")
+ value("_path(context, request, True, '%s' % (view,))")
+
+ >>> translate("context/@@?view")
+ value("_path(context, request, True, '@@%s' % (view,))")
+ """
+
+ if not string:
+ return None
+
+ if not self.path_regex.match(string.strip()):
+ raise SyntaxError("Not a valid path-expression: %s." % string)
+
+ nocall = False
+
+ while string:
+ m = self.re_pragma.match(string)
+ if m is None:
+ break
+
+ string = string[m.end():]
+ pragma = m.group('pragma').lower()
+
+ if pragma == 'nocall':
+ nocall = True
+ else:
+ raise ValueError("Invalid pragma: %s" % pragma)
+
+ parts = string.strip().split('/')
+
+ # map 'nothing' to 'None'
+ parts = map(lambda part: part == 'nothing' and 'None' or part, parts)
+
+ components = []
+ for part in parts[1:]:
+ interpolation_args = []
+
+ def replace(match):
+ start, end = match.span()
+ interpolation_args.append(
+ part[start+1:end])
+ return "%s"
+
+ while True:
+ part, count = self.interpolation_regex.subn(replace, part)
+ if count == 0:
+ break
+
+ if len(interpolation_args):
+ component = "%s %% (%s,)" % (
+ repr(part), ", ".join(interpolation_args))
+ else:
+ component = repr(str(part))
+
+ components.append(component)
+
+ base = parts[0]
+
+ if not components:
+ if len(parts) == 1 and (nocall or base == 'None'):
+ value = types.value('%s' % base)
+ return value
+ else:
+ components = ()
+
+ value = types.value(
+ '%s(%s, %s, %s, %s)' % \
+ (self.symbol, base, self.scope, not nocall, ', '.join(components)))
+
+ value.symbol_mapping[self.symbol] = self.path_traverse
+
+ return value
+
+class NotTranslator(expressions.ExpressionTranslator):
+ zope.component.adapts(IExpressionTranslator)
+
+ recursive = True
+
+ def __init__(self, translator):
+ self.translator = translator
+
+ def tales(self, string, escape=None):
+ """
+ >>> tales = NotTranslator(path_translator).tales
+
+ >>> tales("abc/def/ghi")
+ value("not(_path(abc, request, True, 'def', 'ghi'))")
+
+ >>> tales("abc | def")
+ parts(value('not(_path(abc, request, True, ))'),
+ value('not(_path(def, request, True, ))'))
+
+ >>> tales("abc | not: def")
+ parts(value('not(_path(abc, request, True, ))'),
+ value('not(not(_path(def, request, True, )))'))
+
+ >>> tales("abc | not: def | ghi")
+ parts(value('not(_path(abc, request, True, ))'),
+ value('not(not(_path(def, request, True, )))'),
+ value('not(not(_path(ghi, request, True, )))'))
+ """
+
+ value = self.translator.tales(string, escape=escape)
+ if isinstance(value, types.value):
+ value = (value,)
+
+ parts = []
+ for part in value:
+ factory = type(part)
+ value = factory("not(%s)" % part)
+ value.symbol_mapping.update(part.symbol_mapping)
+ parts.append(value)
+
+ if len(parts) == 1:
+ return parts[0]
+
+ return types.parts(parts)
+
+class ProviderTranslator(expressions.ExpressionTranslator):
+ provider_regex = re.compile(r'^[A-Za-z][A-Za-z0-9_\.-]*$')
+
+ symbol = '_get_content_provider'
+ content_provider_traverser = ContentProviderTraverser()
+
+ def translate(self, string, escape=None):
+ if self.provider_regex.match(string) is None:
+ raise SyntaxError(
+ "%s is not a valid content provider name." % string)
+
+ value = types.value("%s(context, request, view, '%s')" % \
+ (self.symbol, string))
+ value.symbol_mapping[self.symbol] = self.content_provider_traverser
+ return value
+
+class ExistsTranslator(PathTranslator):
+ """Implements string translation expression."""
+
+ symbol = '_path_exists'
+
+ path_traverse = ZopeExistsTraverser()
+
+ def translate(self, *args, **kwargs):
+ value = super(ExistsTranslator, self).translate(*args, **kwargs)
+ if value is None:
+ return
+
+ assert isinstance(value, types.value)
+ parts = types.parts(
+ (value, types.value('False')))
+ parts.exceptions = NameError,
+ return parts
+
+exists_translator = ExistsTranslator()
+path_translator = PathTranslator()
+provider_translator = ProviderTranslator()
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