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IPC6 Developers' Day

Friday October 17 1997, the final day of the Sixth International Python Conference, is Developers' Day, where the Python community will have the opportunity to discuss the future of Python with its creator Guido van Rossum. This provides the Python community with the exciting opportunity to be involved in charting the future course of the Python language and implementation.


Developer's Day Topics

Developer's Day is going to be less formal than the other days of the Python Conference. We have a number of topics, listed below, that are being championed by volunteers. These champions are responsible for presenting brief position statements or proposals, soliciting comments from the audience, and getting the discussions going. While it is very difficult to tell ahead of time which topics will generate the most heat (or light), and which will be non-controversial, we don't intend to let any particular topic go longer than about 45 minutes. By that time, most participants will be burned out anyway.

The day will be roughly divided into six 45 minute sessions, although both the allotment of time per topic, and scheduling of topic per session has not yet been determined. There will be a morning break from 10:30 to 11:00 am, a lunch break from 12:30 to 2:00, and an afternoon break from 3:30 to 4:00 pm. A free-for-all is planned from 4:00 onwards, for those who want to stay late.

Be prepared for impromptu discussions cropping up at any time of the day or night, over lunch, dinner, beers, or even the Monday Night football game where the Redskins will be beating the Cowboys. :-)

Here is the current list of topics, along with their champions. Where possible, a short position statement is given if provided by the champion. Stay tuned to the newsgroup/mailing list for more details. We apologize in advance for any short-changing of times that might occur. There's lots to discuss, and I'm sure more interesting topics will crop up as the conference progresses. If past conferences are any indication, this should be one of the livelier days! :-)

For questions and comments, please email Barry Warsaw, Developers' Day Chair, IPC6

Position Statements

Object Interfaces
Champion: Jim Fulton
Sixth International Python Conference
Developer's Day Session on Language Features or Idioms to
Support Object Interfaces

  The 6th Internationl Python Workshop will feature a
  developers day that provides a place to discuss and debate
  Python language issues "face-to-face".  The subject of one
  of these sessions will be language features or idioms to
  support object interfaces.


    Two of the Fundemental ideas in object oriented development are

    - separation of object interfaces from object
      implementation, and

    - ability to use objects with the same interface but
      different implementations interchangably.

    When used properly, these two features provide many
    benefits, such as safety, stability, flexibility, reuse,
    and so on.

    Unfortunately, most computer languages provide very
    little support for reasoning about or testing
    interfaces.  Worse, many languages provide incomplete or
    missleading interface information.  Compounding the
    problem is that commonly used jargon has many and often
    conflicting interpretations.  For example, the terms
    "class" and "type" may alternately mean interface or
    implementation.  Even the term "interface" can have
    different meanings.  For some, "interface" refers to
    method signatures, while for others, the term connotes
    identical behavior.

    For the sake of this discussion, I will use the term
    interface in the stronger sense.  Two objects have the
    same interface if they have the same abstract behavior
    and are are substitutable wrt the interface. 

    For some time, Python programmers have wanted simple and
    efficient means to be able to test object interfaces.
    Foe example, a function may be willing to accept an
    argument that is either a "number" or a "sequence" and
    must be able to test whether the argument is one or the
    other to decide how it is used.

    As Python is used for larger projects and in a larger
    number of domains, reliability of Python programs is an
    increasing concern.  People would like language support
    to help assure program correctness.  Python 1.5 adds the
    ability to include assertions in programs and recent
    advances in the ability to extend class semantics
    provides the ability to experiment with argument
    interface checking and Meyer's "development by contract"
    It has been suggested that this session might be
    combined with a session on use of static typing to
    support optimization.  I assert that this sort of
    typing is really about implementation, not interfaces.
    I beleave strongly that reasoning about interfaces and
    reasoning about implentation should be kept distinct.
    Some disagree with me on this point.


    The objective of this session is to explore possible
    language features or idioms to support interfaces.


    I would like to follow the following format for this session:

    - Brief overview of the problem,

    - Position statements

    - Discussion

    Participants and non-participants are invited to submit
    *concise* position statements to me (at least 24 hours)
    prior to the session.  Position statements should
    address one or more of the following topics:

    - Needs and requirements for interfaces,

    - Proposals for langauage features or idionms to support

    - Aguments for or against separation of abstract
      interfaces from static typing.

    Time permitting and authors present and willing willing,
    position statements may be presented during the session.
    Note that the entire session is only 45 minutes in
    length, and I want to reserve a significant amount of
    time for discussion.  Position statements must be
    concise.  No more than 5 minutes will be allowed per
    presentations.  If there is not enough time for
    positions to be presented individually, I will do my
    best to summarize.  Concise position statements will be
    included in the proceedings.

I apologize for the lateness of this post.

Combining Python Type and Class Semantics
Champion: Jim Fulton
International Python Conference VI
Developer's Day Session on Combining Python Type and Class

  The 6th Internationl Python Conference will feature a
  developers day that provides a place to discuss and debate
  Python language issues "face-to-face".  The subject of one
  of these sessions will be integration of python types and


    Currently, Python provides two ways of defining new
    kinds of objects:

    - Python classes (written in Python)

    - Extension types (written in C or C++)

    Each approach has it's strengths.  Extension types
    provide much greater control to the programmer and,
    generally, better performance.  Because extension types
    are written in C, the programmer has greater access to
    external resources. (Note that Python's use of the term
    type has little to do with the notion of type as a
    formal specification.)

    Classes provide a higher level of abstraction and are
    generally much easier to develop.  Classes provide full
    inheritance support, while support for inheritance when
    developing extension types is very limited. Classes
    provide run-time meta-data, such as method documentation
    strings, that are useful for documentation and
    discovery.  Classes act as factories for creating
    instances, while separate functions must be provided to
    create instances of types.

    Python programmers are often confused by the differences
    between extension type instances and class instances.

    - A type instance has a meaningful type, but no
      __class__.  A class instance has a meaningful
      __class__, but a meaningless type.

    - To discover a type instance's interface, __methods__
      and __members__ attributes must be inspected.  To
      discover a class instance's interface, it's, __dict__,
      and __class__ attributes must be inspected.

    - A class provides access to method meta-data, a type
      does not.

    - A class instance is created in a standard way, by
      calling it's class. There is no standard way to create
      a type instance.

    - A class can be subclassed but a type can not (usually).

    - class instance methods have discoverable method
      signatures, but type instance methods do not.


    The objective of this session is to to take a
    step toward integrating classes and types.


    I would like to follow the following format for this

    - Brief overview of the problem,

    - Position statements

    - Discussion

    Participants are invited to submit position statements
    to me (at least 24 hours) prior to the session.
    Position statements should address one or both of:

    - Requirements for or desirability of class/type

    - Proposals or approaches for class/type integration

    Time permitting and author's willing, position
    statements may be presented during the session.

Champion: Martin v. Loewis
  Python's text processing today is based on the built-in string type,
  which allows to represent byte sequences. Most character processing
  modules assume one byte per character.
  In order to support more than one language, or to support languages
  with more than 256 characters, some sort of wide string or multi
  byte character string processing is required.
  One approach is to support Unicode, the other is to allow for
  arbitrary character sets (the approaches are not necessarily
  Tightly related to the character sets is the user interface: The
  user needs to enter information in her native language, and wants to
  get results displayed using that language.
  When it comes to introducing new interfaces in Python, a top
  requirement is to make the modules uniform across
  platforms. Unfortunately, there is no straight-forward solution, as
  nationalization issues are handled differently among platforms.

  The objective of this session is to communicate the needs of both
  end users and application programmers for internationalization
  support in Python.

  Participants are invited to contribute to the following issues:
  - reports about I18N projects in general, or I18N projects involving
    Python in particular
  - application programmer requirements for I18N in the core language
    and the standard libraries
  - approaches to harmonizing new interfaces among platforms

Python-C/C++ Integration Tools
Champion: David M. Beazley

Python is being used increasingly as an extension language for C and
C++ systems.  A number of tools such as SWIG, Modulator, GRAD,
etc... have also been developed to ease the process of C/C++ extension
writing.  However, there are also a number of concerns including (but
not limited to) the following :

    -  Are automated tools effective at building Python extensions?

    -  Can Python be used effectively with existing C/C++
       applications?  What are the limitations?

    -  Separation of C/C++ implementation and the Python interface.
       (i.e. should C/C++ programs know that Python is involved?)

    -  How do you effectively manage C/C++ objects in Python?

    -  How do you use advanced C++ features such as templates, 
       exceptions, namespaces, etc...

    -  Integration with other Python extensions (Numeric Python,
       extension classes, etc...).


The purpose of this session is to discuss the state of Python-C/C++
integration tools and techniques. Participants are invited to
contribute to any number of the following topics (or any other closely
related topic) :

    -   Successful use of Python extension tools.

    -   Failures and shortcomings of existing approaches.

    -   Alternative and novel Python extension writing techniques.

Champions: Robin Friedrich
So far the String-SIG's only deliverable item has been an enhanced
regular expression module.  Since beta versions of this module are now
available for testing, should the SIG be shut down, or are there new
tasks to be considered?  Some suggestions for a new objective have
been: a Unicode string type; internationalization issues; code for
implementing and generating parsers.

Inter-Language Unification (ILU) and Python
Champion: Jody Winston
My goal for this session is to moderate and to initiate the discussion
between application developers that use Python and ILU. 


This session will discuss the design and development of applications
that use ILU and Python.

	Applications using ILU and Python
	Sample Discussion Topics
		New CORBA bindings for Python
		ISL vs IDL
		Integration with other languages

		Debugging applications

	State of the Distributed Object SIG

I apologize for the lateness of this post.