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version 1130, Mon May 19 17:33:59 2003 UTC version 2107, Mon Nov 21 04:21:13 2005 UTC
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 Fixes and Enhancements since Version 0.5 alpha 1  Fixes and Enhancements since Version 0.5 alpha 3
   
  Changed, Enhanced, or Newly Deprecated Features   - The 'peak' script is now an .exe on Windows, using setuptools' "entry point"
      system.
   
  - Added a ZConfig schema for 'running.commands.EventDriven' applications,   - PEAK no longer bundles any software that can be obtained automatically from
    a ZConfig component definition for adaptive tasks, and a running shortcut     PyPI.  Running PEAK's setup script will attempt to download and install
    called 'EventDriven'.  It should now be possible to do this::     the needed packages.  (Note that development snapshots of PEAK may require
      development snapshots of related packages.)
      #!/usr/bin/env peak EventDriven  
    - Added a series of new QueryDM and EntityDM convenience features.  See
    at the top of a ZConfig file formatted according to the new schema, and     "Making Data Managers easier to use":http://www.eby-sarna.com/pipermail/peak/2005-May/002296.html
    have it run.  Unfortunately, so far the only type of task that can be     for a complete list and explanatory documentation.
    included is 'running.daemons.AdaptiveTask', which doesn't actually *do*  
    anything.   - Changed 'running.lookupCommand()' to use the command's 'getCommandParent()'
      method, so that commands using the '--config' option will utilize the
  - Added 'zconfig.schema' URL scheme that loads an enhanced ZConfig schema     specified configuration(s) to lookup subcommands.
    object that can act as a command line interpreter using the 'peak' script.  
    To use it, run 'peak zconfig.schema:urlToSchema urlOfConfig'.  Or, add   - Added a '-c/--config' option to PEAK bootstrap commands to load an .ini
    a line like this::     configuration file in a new service area before executing any subcommands.
   
      #!/usr/bin/env peak zconfig.schema:pkgfile:some.package/schema.xml     This allows you to do things like::
   
    to the top of a configuration file, and make the configuration file          peak launch -c bulletins ref:sitemap@sitemap.xml
    executable.  Note that the schema specified must convert to an object  
    that's usable with the commands bootstrap framework.  Also note that     which loads the 'bulletins' configuration file before launching the sitemap.
    if you have a local PEAK_CONFIG file, you can add a 'peak.running.shortcuts'     Note that if you are subclassing 'commands.Bootstrap' you can suppress this
    entry to shorten the URL reference in your #! line.  E.g.::     option using 'options.reject_inheritance("-c","--config")' in the body of
      your subclass' class definition.  You may wish to do this if your
      #!/usr/bin/env peak mySchema     application's subcommands must run in the same service area as the parent
      command.  (E.g. if the parent command expects the subcommand to partake in
    will suffice if you have defined 'peak.running.shortcuts.mySchema' as     a transaction controlled by the parent command.)
    'naming.LinkRef("zconfig.schema:pkgfile:some.package/schema.xml")'.  
    - Added a 'value' property to 'model.Enumeration', so that you can access
    There is also a 'peak ZConfig urlOfSchema urlOfConfig' variant, that was     an enumeration instance's value (i.e., the value it hashes and compares
    added to support putting '#!/usr/bin/env peak ZConfig' at the top of     equal to)
    schema files, but unfortunately that's not valid XML.  
    - Added a 'binding.hasParent(component,parent)' API function, which is
  - Standardized file-based URL syntaxes (e.g logfiles and lockfiles) to     specially optimized for use with generic functions, so that you can
    follow RFC 1738/2396, and Python 'urllib'.  This shouldn't affect much     define generic function methods that apply only within some part of a
    besides the canonical forms of the URLs.  Added 'pkgfile:some.pkg/filepath'     component hierarchy.
    URL syntax for ease of referring to files near modules.  (A convenience  
    intended mainly for referencing ZConfig schemas.)   - PEAK no longer supports Python 2.2; Python 2.3.4 or better is required.
   
  - Added the UML 1.4 metamodel, and thus the ability to load UML 1.4   - The kjbuckets extension module is no longer built and installed by default;
    models encoded in XMI 1.1.     you must explicitly enable it with a '--with-kjbuckets' flag passed to
      'setup.py'.  Please port your code as soon as practical, this option will
  - Added support in the mof2py code generator for "unprefixing" enumerated     go away soon.
    values, so that UML and other metamodels' enumerations work correctly  
    when loading from XMI.   - Use of the included 'kjbuckets' module is now DEPRECATED, due to increasing
      bitrot.  Aaron Watters originally wrote this extension for Python 1.2, and
  - 'binding.Acquire()' now accepts a 'default' value argument, and     it has not been well-maintained for newer versions of the Python/C API.
    'binding.New()' no longer accepts the 'bindToOwner' flag.     Instead of 'kjSet' objects, use the Python 2.3 'Set' type, and instead of
      the 'kjGraph' type, use the new 'Graph' type in 'peak.util.Graph'.  Some
  - There is a new 'binding.IComponentKey' interface that is used to implement     porting effort may be required, as these types are not precisely the same
    'IComponent.lookupComponent()'.  Now you can implement this interface,     in signature as the originals.
    or create an adapter for it, in order to make an object usable as an  
    argument to 'binding.lookupComponent()' - and therefore usable as a key   - The '_setNS()' method of the 'peak.util.SOX.ISOXNode_NS' interface has
    for 'binding.bindTo()' or 'binding.bindToSequence()'.  Not that it's     changed signature, due to a lack of use of the second argument in the code
    necessarily very useful to do so; you're probably better off simply     base, and its dependency on 'kjbuckets'.
    creating a naming scheme.  But it might be useful for lookups done  
    in the context of classes, since naming schemes aren't usable there.   - The old 'peak.security' implementation has been removed, and replaced with
    (It was actually added in order to factor out all the type testing that     a simpler, more flexible implementation based on generic functions (using
    'lookupComponent' used to do, so it doesn't matter if it's useful for     less than half the code and seven fewer interfaces).  Complete documentation
    much else.)     and API tests for the new implementation can be found in 'rules.txt' in the
      'peak.security' package directory.
  - PEAK has been refactored to avoid the use of 'isImplementedBy()' and  
    similar introspection, in favor of 'adapt()'.  As a result, some     Also, the new implemetation does not require redundant
    'peak.naming' interfaces have changed.  This should not affect you     'security.allow(security.Anybody)' declarations just because you've declared
    if you are only subclassing PEAK-provided naming components and not     other permissions for a class, so these declarations have been removed from
    implementing these interfaces "from scratch".  However, the various     ``peak.web``.  They don't do any harm, however, so you can leave them in
    'isAddress', 'isAddressClass', 'isResolver', and 'isName' APIs have     your own code as long as you change them to use 'binding.metadata()' instead
    also been removed, as they were based on 'isImplementedBy()'.     of the deprecated 'security.allow()'.
   
  - REMOVED ability to use '__implements__' and '__class_implements__' to   - 'security.allow()' is now DEPRECATED; please use 'binding.metadata()'
    declare support for interfaces.  Use 'protocols.advise()' or a related     instead.  (There is no change to the calling signature, but
    API to do this now.  The 'protocols' package is available automatically     'binding.metadata' accepts any metadata, not just permissions.)
    from 'peak.api'.  
    - Added 'peak.running.options', a new option-parsing framework that extends
    Similarly, the ability  to use 'isImplementedBy()' with interfaces declared     'optparse' to support the PEAK 'commands' framework.  Command instances
    by PEAK is REMOVED.  You can still use 'isImplementedBy()' with Zope     can now refer to 'self.parsed_args' to find their non-option arguments,
    interfaces, of course, but we recommend you switch to 'adapt()', which     and to trigger setting of their attributes (or calling of methods) based on
    should work with both PEAK and Zope interfaces.     their raw arguments from 'self.argv'.  See 'options.txt' in the
      'peak.running' package directory for a complete tutorial.
  - Replaced all use of 'zope.interface' with 'protocols' package because  
    the 'protocols' package:   - There is now a 'binding.initAttrs()' function that can be used to initialize
      an object's attributes from e.g. constructor keyword arguments, similar to
    * is considerably smaller and simpler than 'zope.interface'     how 'binding.Component' and 'binding.Attribute' constructors work.
   
    * produces Interface objects that can be inspected with the Python   - Security permissions can now be declared as attribute metadata.
      'pydoc' and 'help()' tools  
      That is, instead of doing declarations like this::
    * supports and implements the PEP 246 'adapt()' protocol  
           class Foo:
    * transparently supports transitive adaptation - i.e. if adapter AB              bar = binding.Require("Something", permissionNeeded=SomePerm)
      adapts from A to B, and adapter BC adapts from B to C, then an adapt(x,C)  
      where 'x' is an 'A', will be implemented as BC(AB(x)).          class AnElement(model.Element):
               class someFeature(model.Attribute):
    * Supports "open protocols" that allow you to "superclass" a protocol                  permissionNeeded = SomePerm
      to create a subset protocol; objects that support the first protocol  
      will automatically support the subset protocol.  For example, if one     you can (and should) now do them like this::
      person defines a "dictionary" protocol, someone else can create a  
      "read-only dictionary" protocol, and all objects supporting the          class Foo:
      "dictionary protocol" will be considered to implement the "read-only              bar = binding.Require("Something", [SomePerm])
      dictionary" protocol.  
           class AnElement(model.Element):
    * can interoperate with other interface packages, including Zope's, but              class someFeature(model.Attribute):
      does not require them                  metadata = [SomePerm]
   
    * works with module inheritance (for everything but moduleProvides(), and     or this::
      we should get to that by 0.5a2)  
           class Foo:
    * lets you use Interfaces as abstract base classes (i.e., you can              binding.metadata(bar = [SomePerm])
      inherit from an interface and turn it into an implementation, and  
      you can define default attribute values or method implementations in          class AnElement(model.Element):
      your interfaces  
               binding.metadata(someFeature = [SomePerm])
    * Lets you mix interface declarations from any number of frameworks and  
      any number of interface types, in a single 'implements()' or              class someFeature(model.Attribute):
      'classProvides()'                  # ...
   
    * uses adaptation as the fundamental approach to dealing with interfaces,     It isn't necessary to enclose metadata in brackets, but it helps to
      and avoids the use of 'isImplementedBy()'.  In the *rare* case that you     emphasize its annotational nature.  Also note that e.g. 'web.bindResource()'
      need to introspect rather than adapt, you can always call adapt() and     needs 'metadata' to be a keyword argument.
      check the result.  (But introspection usually means that you're using  
      interfaces as a form of metadata; it's better to create an explicit   - The 'permissionNeeded' attribute of 'model.Feature' and 'binding.Attribute'
      interface that provides the metadata you seek, and adapt to that     objects is now DEPRECATED.  See examples above for how to upgrade, and please
      interface, than to use interfaces as data.)     switch to using metadata as soon as practical.  In addition the
      'security.IGuardedDescriptor' interface has been removed, because it was
    Most of these features are unavailable in 'zope.interface', and some have     only used in connection with the 'permissionNeeded' attribute mechanism.
    been declared by the Zope Pope to be unacceptable or undesirable features  
    for Zope interfaces.  (Others may be available in some form in future   - Added a new "attribute metadata" mini-framework to 'peak.binding'.  This
    versions of Zope X3.)  So, we no longer require or distribute     framework makes it possible to declare arbitrary metadata about attributes,
    'zope.interface'.     using either a class advisor ('binding.metadata()', similar in form and
      function to the existing 'security.allow()') or using a 'metadata' attribute
  - The signatures of the 'getObjectInstance()', 'getStateToBind()', and     of attribute bindings (which is the second positional parameter in all
    'getURLContext()' methods in the 'peak.naming' package have changed, to     the standard bindings like 'Make', 'Obtain', etc.).  Over time, existing
    place the context or parent component as the first, non-optional argument.     metadata mechanisms will be refactored to use this new mini-framework,
    (If you don't know what these methods are for, you don't need to do anything     instead of the various integrated ad-hoc mechanisms that exist now (like
    about this, as they are part of the naming package's extensibility     the 'permissionNeeded' attribute).  For more information on how the new
    framework.)     metadata hooks work, including doctest examples, see the 'attributes.txt'
      file in the 'peak.binding' package, under the heading "Attribute Metadata".
  - 'binding.bindTo()' now accepts a 'default=' argument, whose value will be  
    used in case of a 'NameNotFound' error.   - Added a new function, 'binding.activateClass()', that can be used to
      activate any bindings in the class.  This can now be used in place of
  - DEPRECATED 'naming.ParsedURL'.  It will disappear in 0.5 alpha 3 or beta.     subclassing a PEAK base class or using a PEAK metaclass.  In future, this
    It is replaced by the new 'naming.URL.Base'.  The 'naming.URL' package     will be integrated into PEAK attribute descriptors such that defining a
    provides a new URL parsing framework based on 'peak.model'.  Upgrading from     descriptor within a class' body is sufficient to cause this function to be
    'ParsedURL' to 'URL.Base' is trivial for ParsedURL subclasses that used     invoked.
    only the 'scheme' and 'body' fields, and in fact may not require any  
    changes except for the choice of base class.  Also, the 'retrieve()' method   - 'binding.IBindingNode' was REMOVED, consolidated into 'binding.IComponent',
    of URLs is deprecated; please begin defining the 'getObjectInstance()'     as its various individual methods have been replaced with generic functions
    method instead.  This is to cut down a bit on the number of ways that the     in the existing 'binding' API.  For example, 'binding.getParentComponent(x)'
    naming package spells the idea of retrieving something!     should be used in preference to 'x.getParentComponent()' unless it is
      a requirement that 'x' implement the full 'binding.IComponent' interface.
    For more complex URL classes, the '__init__' methods go away, 'parse'     This makes it easier to define what 'binding.getParentComponent()' and
    methods change slightly, and explicit field definitions (using     'binding.getComponentName()' will mean for non-component types, as you do
    'model.structField' or similar) are required.  See PEAK's 'URL.Base'     not have to define an adapter class with all of the 'IBindingNode' methods.
    subclasses for examples.  There is also a sophisticated parsing and     Also, this makes PEAK itself cleaner, as we often weren't bothering to
    formatting framework (see the 'peak.naming.URL' and 'peak.util.fmtparse'     properly implement the full 'IBindingNode' interface anyway.
    modules) that can be used in place of the old regex-based approach.  
      In addition, 'binding.suggestParentComponent()' is now also a generic
  - Added 'peak.util.fmtparse', a parsing and formatting framework, and     function, dispatching on the target (i.e. child) object.
    integrated it with 'peak.model' so that any element type can have a  
    syntax for parsing from, or formatting to, a string.   - 'naming.IReferenceable' was REMOVED, as it is not in use anywhere in PEAK.
      This will be replaced with a generic function when we do actually need this
  - Added 'binding.whenAssembled(...)' as syntax sugar for     functionality.
    'binding.Once(...,activateUponAssembly=True)'.  
    - There is a new 'config.getStreamFactory' generic function, to make it easy
  - Removed 'LOG_XYZ' convenience functions from 'peak.api', and refactored     to accept URLs, filenames, or 'naming.IStreamFactory' objects as the source
    'peak.running.logs' to use a PEP 282-like interface, 'running.ILogger'.     of a "file".
    Under the new scheme, messages must be sent to a specific entry point  
    (e.g. 'self.logger.warning("foo")').  Components can bind an attribute     Its typical usage is just::
    directly to a logger object, or via configuration properties or utilities.  
    PEAK components that do logging all define a 'logger' attribute, bound         factory = config.getStreamFactory(self,source)
    to a configuration property in the 'peak.logs' property namespace.  By         stream = factory.open('t')  # open for reading in text mode
    a default in 'peak.ini', 'peak.logs.*' is configured to output messages  
    of 'WARNING' priority or higher to 'sys.stderr'.     where 'source' is a string or a 'naming.IStreamFactory', and 'self' is a
      component to be used as lookup context.  The returned 'factory' is a
    For compatibility with the PEP 282 logging package, a 'logging.logger:'     'naming.IStreamFactory' that can then be '.open()'-ed for reading, or used
    URL scheme has been added; looking up the URL '"logging.logger:foo.bar"'     in other ways as needed.
    is equivalent to 'logging.getLogger("foo.bar")', unless the 'logging'  
    package is not available, in which case the configuration property     If you have special objects that you'd like to be able to treat as stream
    'peak.logs.foo.bar' will be looked up in the target context of the     sources, you can register them by defining an extension, e.g.::
    lookup.  Optionally, you can configure the 'logging.logger' URL scheme so  
    that it only uses PEAK loggers, and never uses the PEP 282 loggers.      [config.getStreamFactory.when(MyType)]
       def getStreamFactory(context,source):
  - Added 'binding.metamethod()' wrapper for metaclass methods that might          """Return a naming.IStreamFactory for 'source' (a 'MyType' instance)"""
    not be accessible from their instances if the instances (classes) also  
    defined the method for *their* instances.  You must now use this wrapper     Wherever practical, as we encounter them, we'll be changing PEAK API's that
    on any such metaclass-defined methods, as PEAK no longer works around     take filenames to also accept stream sources.
    this via the 'x.__class__.foo(x,...)' trick that was used previously.  
    In particular, if you have metaclass definitions of 'getParentComponent',   - Added an optional 'base' argument to 'naming.parseURL()', to allow parsing
    '_getConfigData', 'getComponentName', or 'notifyUponAssembly', you need     URLs relative to a base URL.  For a URL scheme to support this, it must
    to wrap them with 'binding.metamethod' now.     implement the new 'naming.IBaseURL' interface.  See the
      'peak.naming.factories.openable' module for example implementations.
  - Made 'NOT_GIVEN' and 'NOT_FOUND' recognizable by humans (they 'repr'  
    and 'str' to their names) and by Python (they can be pickled, and   - Added a 'data:' URL scheme, implementing RFC 2397 (although it's not as
    when restored they come back as the same object).     strict in its parsing of the content type and parameters as the RFC calls
      for).  This is a semi-convenient way to provide configuration data in-line,
      since a 'data:' URL can be a 'config.getStreamFactory()' source.
  Corrected Problems  
    - Added 'config.processXML()', a function that provides a high-level,
  - Fixed a problem in ZConfig 'schema.dtd'; I used 'PCDATA' where I should've     configuration-driven interface to 'peak.util.SOX.NegotiatingParser'.  This
    used 'CDATA'.     simple front-end lets you supply as little as a configuration context and
      a stream source, to do XML processing of arbitrary complexity, controlled by
  - Fixed misc. problems with 'fromZConfig()' component constructor     the configuration of the context.
   
  - Fixed source distributions missing essential setup files   - Added 'config.XMLKey()', an 'IConfigKey' type that can be used to register
      configuration values for XML attribute and element names under specified
  - Fixed a problem with assembly events, where a parent component that didn't     XML namespace URI's.  Also, there are now '[XML Attributes for nsuri]' and
    need assembly notification, wouldn't ever notify its children of assembly     '[XML Elements for nsuri]' section types available for use in .ini files.
    if they requested the notification after the parent had already received     (Replace 'nsuri' with the appropriate XML namespace URI, or use '*' for a
    it.     wildcard.)
   
  - Fixed 'naming.lookup()' and related APIs not setting the parent component   - 'web.IResource' is gone, replaced by 'web.IPlace'.  The notion of a place is
    of created objects without an explicitly supplied 'creationParent' keyword     broader than the notion of a resource, and we will soon need to have
    argument.  This used to "sort of work" when we had implicit configuration     other "location" objects that implement 'IPlace'.
    parents, but was broken when we went "all explicit" for 0.5 alpha 1.  
    - In order to support obtaining the line and column locations of problems in
  - Fixed a problem where initializing single-valued immutable fields of     XML files, we are now using Python 2.4's version of the 'pyexpat' module,
   'peak.model' types did not perform type/value normalization.     built as 'peak.util.pyexpat'.
   
  - Fixed a problem where bindTo would use the attribute name as the   - There's a new class, 'config.IniLoader', that can be used to lazily load
    default value for a lookup, if the requested name/property/utility     .ini files as configuration.  'IniLoader' instances have an 'iniFiles'
    was not found.     attribute that lists the configuration sources (filenames/URLs/factories)
      to be used, and automatically load the .ini files as soon as you try to get
  - Fixed 'mof2py' generator script not working     any configuration data for them.  Previously, similar functionality was only
      available via 'config.makeRoot()'.
   
      Also, there's now an 'ini' reference type that instantiates an 'IniLoader'
      for one or more addresses.  You can use it like this::
   
        [Named Services]
   
        some.example = naming.Reference('ini',
            ['pkgfile:peak/peak.ini', '/etc/something.ini']
         )
   
        another.example = naming.LinkRef(
            'ref:ini@pkgfile:peak/peak.ini||/etc/something.ini'
         )
   
      The two examples above will each load the same pair of specified .ini files.
      You can also directly instantiate an 'IniLoader', as in::
   
        cfg = config.IniLoader(self, iniFiles=['pkgfile:peak/peak.ini'])
   
      Attempting to look up any configuration properties via the 'cfg' object
      will cause it to load the specified .ini file.
   
    - 'config.fileNearModule()' is DEPRECATED, in favor of 'config.packageFile()'.
      The latter returns a 'naming.IStreamFactory', which is more suitable for
      working with e.g. module data files compressed in a zipfile.  Uses of
      'fileNearModule()' that were being passed to 'config.loadConfigFile()' can
      be safely changed to 'config.packageFile()' without needing any other code
      changes, but if you were directly using 'fileNearModule()' as a filename,
      you will need to rewrite appropriately.
   
    - 'config.loadConfigFile()' and 'config.loadConfigFiles()' now accept URLs,
      'naming.IStreamFactory' objects, and other 'config.getStreamFactory()'
      targets as well as filenames.  This was primarily added to support use of
      'config.packageFile()' or 'pkgfile:' URLs, in place of using
      'config.fileNearModule()'.
   
    - The 'naming.IStreamFactory' interface now has an 'address' attribute, which
      is the string form of the canonical URL of the target stream.  This was
      added to make it easier to e.g. report errors in a stream that's being
      parsed, since the parser only needs the factory in order to report the
      location of an error.  (Note: if you implement 'naming.IStreamFactory', be
      sure to add this attribute to your implementations.)
   
    - The 'peak.util.WSGIServer' module has been moved to the
      'wsgiref.simple_server' module.  The 'wsgiref' reference library for WSGI
      (aka PEP 333) is now distributed with PEAK.
   
    - Added a 'WSGI' command to the 'peak' script, to allow you to run "foreign"
      (i.e. non-PEAK) PEP 333 applications in PEAK's various servers and
      launchers.  Basically, by prefixing 'WSGI' before the import specifier, you
      can now run such foreign apps.
   
      For example::
   
          peak launch WSGI import:some_app.application
   
      will run 'some_app.application' in the local web browser, and::
   
          peak CGI WSGI import:some_app.application
   
      will run it under the CGI/FastCGI runner.  Similarly, you can use this in
      the "Command" spec for the "peak supervise" pre-forking FastCGI supervisor
      subsystem.
   
    - There is a new 'running.IWSGIApplication' interface, for PEP 333-compliant
      "application" objects, and all of PEAK's provided applications now implement
      it instead of 'running.IRerunnableCGI'.  If you write your apps to the newer
      interface, they'll be portable to any PEP 333-compliant web server, not just
      the PEAK CGI, FastCGI, and "supervisor" containers.  There is a simple
      adapter that allows 'IWSGIApplication' objects to run in the CGI-based
      containers, but not the other way around, so using 'IRerunnableCGI' directly
      now limits your portability.  (For example, the "peak launch" and "peak
      serve" commands will soon require 'IWSGIApplication', and will not support
      'IRerunnableCGI' any more.)
   
      Of course, if you use the 'peak.web' framework, you don't need to worry
      about any of this; your apps will automatically be wrapped as
      'IWSGIApplication', and run in any PEAK server or gateway.
   
    - Most 'peak.web' interfaces have changed significantly.  If you implemented
      anything based on the older interfaces, and it still works, it's sheer
      bloody luck.  In particular, note that every method in 'web.IWebTraversable'
      now has different inputs and/or outputs than before.  Please read the new
      interface docs and update your code!  The changed interfaces offer much
      more flexibility and functionality than before, but they will require you to
      update your code.
   
    - 'web.ContainerAsTraversable' has been removed.  It was redundant, since the
      new default traversal mechanism used by 'Traversable' and 'Decorator' now
      handles getitem, getattr, and views.
   
    - Added Zope 3-like "namespaces" to 'peak.web'.  Path segments in a URL
      may be prefixed with '"++some_id++"' in order to invoke a corresponding
      namespace handler registered under '"peak.web.namespaces.some_id"'.
      Namespace handlers must implement 'web.INamespaceHandler', and they are
      supplied with the original path segment as well as the separated namespace
      and name.  Also, as in Zope 3, '"@@foo"' is a shortcut for '"++view++foo"'.
      Builtin namespaces at this time include 'view', 'item', 'attr', 'skin', and
      'resources'.  'skin' treats the rest of its path segment as a skin name,
      and sets the current skin, while 'resources' begins traversal to resources
      found in the current skin.  The other namespaces are as described at:
   
      "Resources and traversal in peak.web":http://www.eby-sarna.com/pipermail/peak/2004-August/001712.html
   
    - Fixed several 'peak.events' bugs, as reported by Vladimir Iliev, Yaroslav
      Samchuk, and Alexander Smishlajev:
   
      * 'events.AnyOf' could hold multiple references to a single event source,
        and nesting 'AnyOf()' calls could leak references to the nested events.
   
      * 'events.subscribe()' had a potential race condition wherein a callback
        could be invoked after its weak reference was garbage collected, leading
        to bizarre error messages about 'self' being 'None'.
   
      * 'select()' could be called on select event objects even if there were
        no current subscribers to the event, potentially leading to calling
        'select()' on a closed socket.
   
      * Non-default signal handlers were remaining installed even when there
        were no current subscribers to the applicable event, as long as a
        reference to the event object existed.
   
      As a result of these changes, certain I/O event types (esp. signals and
      stream readable/writeable events) are now longer-lived.  For example,
      signal event objects are now immortal, and the read/write event for a
      particular 'fileno()' will be reused for as long as its supplying
      'Selector' or 'EventLoop' instance exists.  (Previously, weak references
      were used so that these objects would be recycled when not in use.)
   
    - Added 'config.registeredProtocol()' API, that supports defining named and
      local protocols.  This allows easy emulation of Zope 3's "named" and "local"
      adapters and views.
   
    - 'binding.Component' objects no longer support instance configuration at
      runtime (i.e., they no longer implement 'config.IConfigurable').  If you
      need a component to be configurable at runtime, you must now derive from
      (or mix in) 'binding.Configurable' instead.  If you get errors about
      a missing 'registerProvider' attribute, or about being unable to adapt to
      'IConfigurable', try changing your base class from 'binding.Component'
      to 'binding.Configurable', or add it as a mixin if you're deriving from
      a class that uses 'binding.Component' as its base.
   
    - 'binding.IComponent' no longer derives from 'config.IConfigurable' or
      'config.IConfigMap', only 'config.IConfigSource'.  This means that
      'IComponent' no longer guarantees or requires the presence of the
      'registerProvider()' method: now only 'config.IConfigurable' does that.
   
    - The 'config.IConfigMap' interface is now DEPRECATED.  Use
      'config.IConfigurable' instead.  The '_configKeysMatching()' method
      of 'IConfigMap' was moved to 'config.IConfigSource', so if you've
      implemented a custom 'IConfigSource', be sure to add this method.
   
    - 'web.ISkinService' and 'web.ILayerService' were consolidated into
      'web.IInteractionPolicy', because the need to have configurable
      implementations of these services is negligible.  That is, the
      corresponding property namespaces ('peak.web.skins' and 'peak.web.layers')
      are more than adequate as registries.
   
    - Removed 'peak.running.timers' and 'peak.util.dispatch'.  Neither was in
      active use, and both are being replaced by the new generic functions
      package in PyProtocols.
   
    - The 'config.iterParents' API is now moved to 'binding.iterParents', and all
      'binding' functions that walk the component hierarchy use it.  It has also
      been changed to avoid infinite loops in the case of a pathological
      component structure.
   
    - The 'persistence' package has been moved to 'peak.persistence' to avoid
      conflicts with ZODB3 and the latest version of Zope 3.  It will eventually
      be phased out, but for now this move is the simplest way to get it out of
      the way.
   
    - The 'peak.util.SOX' module now uses only one parser, based directly on
      'expat', instead of using SAX.  The new parser expects a new node interface,
      'IXMLBuilder', but adapters from the previous interfaces ('ISOXNode' and
      'ISOXNode_NS') are supplied for backward compatibility.  All of PEAK's
      direct XML handling (currently just 'peak.storage.xmi' and
      'peak.web.templates') have been refactored to use the new interface.  Some
      parsing classes (such as 'ObjectMakingHandler', 'NSHandler', and
      'DOMletParser') are no longer available.
   
    - 'peak.web' no longer uses Zope X3 for HTTP publishing support; it has been
      refactored to use a "simpler, more uniform architecture":http://www.eby-sarna.com/pipermail/peak/2004-May/001462.html
      See also "more on the architecture":http://www.eby-sarna.com/pipermail/peak/2004-June/001482.html
      and subsequent posts in that thread.
   
      As a consequence, "various features have been removed":http://www.eby-sarna.com/pipermail/peak/2004-June/001500.html
      from 'peak.web', for possible return at a future date.  Here is a rough
      outline of the changes made so far:
   
       * The 'pageProtocol', 'pathProtocol', and 'errorProtocol' machinery are
         gone.  They will be replaced in the future with an explicit "controller"
         wrapping mechanism to allow application-specific renderings of the same
         underlying components.
   
       * The Zope 'request' and 'response' objects are gone, along with all of
         their special handling for cookies, character sets, form variables,
         automatically marshalling parameters to functions, etc.  These items of
         functionality will be gradually replaced by functions in 'peak.web.api'.
   
         As a result of this, arbitrary functions and methods can no longer be
         used as web pages; instead, functions and methods to be published must
         use the same inputs and outputs as the 'IHTTPHandler.handle_http()'
         method.
   
       * The 'IWebPage', 'IWebInteraction', 'ITraversalContext', 'Traversal',
         'TraversalContext', and 'Interaction' interfaces and classes no longer
         exist, as they are unneeded in the new architecture.  Instead of
         having a central 'IWebInteraction' that's referenced by numerous
         'ITraversalContext' objects, the new approach uses an 'environ' mapping
         for most functions.  For access control, a 'security.IInteraction' is
         now used, whose function is limited to security checks.  Most
         functions previously performed by 'IWebInteraction' have moved to
         'IInteractionPolicy' or to 'peak.web.api' functions operating on
         'environ' mappings.
   
       * Web exceptions can define a 'levelName' attribute that determines the
         severity level with which the exception will be logged.  This allows
         one to e.g. avoid logging tracebacks for 'NotFound' errors.
   
       * Various interface calling signatures have changed slightly.  For example,
         'IAuthService.getUser()' now accepts an 'environ' mapping instead of
         an interaction.  'IInteractionPolicy.newInteraction()' now takes keyword
         arguments, but not a 'request'.  The 'IWebTraversable' interface no longer
         has a 'getObject()' method, and the 'IWebException.handleException()'
         method signature has changed as well.  Finally, all methods that
         previously accepted 'ITraversalContext' (such as
         'IDOMletState.renderFor()') now expect 'environ' mappings.
   
       * 'web.TestInteraction' was replaced with 'web.TestPolicy', and
         'web.Interaction' was removed, since 'IWebInteraction' is no longer part
         of the architecture.
   
    - The 'log()' method of PEAK loggers ('logs.ILogger') now accepts a level name
      *or* a number, for convenient invocation.
   
    - SQL transaction semantics have changed.  Now, issuing an SQL statement
      *always* causes the connection to join the active PEAK transaction, even if
      you request that the SQL be issued "outside" a transaction.  Such SQL will
      be issued outside of the *database* transaction, but not outside of the
      PEAK transaction.  This simplifies the overall processing model for dealing
      with "untransacted" SQL such as Sybase DDL or read-only Oracle transactions.
      (In particular, the requirement that triggered this change was to allow
      Oracle read-only transactions to be released at the end of the current PEAK
      transaction.)  Also, got rid of the now-meaningless 'begin' command in n2.
   
    - The 'events.IEventSource' interface now returns a 'canceller' function from
      the 'addCallback()' method, allowing you to cancel a previously-scheduled
      callback.  This fixes a memory leak and performance problem with
      'events.AnyOf()', which previously could accumulate unneeded callbacks on
      the sources it was monitoring.  Note that if you have developed any custom
      event sources with 'addCallback()' methods, you must make sure that they
      return a canceller from now on.
   
    - Added 'ref:factory@addr1||addr2' URL scheme that maps to a corresponding
      'naming.Reference("factory",["addr1","addr2"])'.  'factory' can be either a
      dotted import string referencing a 'naming.IObjectFactory', or you can
      define a factory in the 'peak.naming.factories' property space.
   
    - Added a 'zconfig.schema' factory, so that 'ref:zconfig.schema@streamURL'
      will load a schema loader.  Schema loaders are themselves object factories,
      so you can do something like::
   
        [Named Services]
        peak.naming.factories.myschema = \
            naming.LinkRef('ref:zconfig.schema@pkgfile:mypkg/Schema.xml')
   
      in order to make URLs like 'ref:myschema@filename' work.  Note, by the way,
      that the above could also read::
   
        [Named Services]
        peak.naming.factories.myschema = \
            naming.Reference('zconfig.schema',['pkgfile:mypkg/Schema.xml'])
   
      which runs somewhat faster at lookup time.  Similarly, one can also use
      'naming.Reference("myschema",["somefile"])' in place of a
      'naming.LinkRef("ref:myschema@filename")'.  As well as being faster, for
      some use cases it's easier to 'Reference' directly than to glue together
      a 'ref:' URL string.
   
  - Fixed model.Element not getting parent component set when passed as a  
    constructor argument.  
   
  - Fixed property/utility lookups not working correctly on model.*  
    objects.  
   
  - Fixed IndentedStream generating all-whitespace lines  
   


Generate output suitable for use with a patch program
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  Added in v.2107

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