Revision history for Perl extension Class::Contract.

Future Plans and Ponderings:

  - Damian's Legacy
    o  Class Flattening and shortening
    o  Easier mechanisms for porting code to use CC. Like allowing 
       pre-declared subroutines to be assimilated into contract

  - Update documentation...
    o  better examples of using objects in contracts
    o  functions: scalar_attrs, array_attrs, hash_attrs, private, clon

  - Constructor
    o  Allow user-defined default values for attributes
    o  Ponder whether or not it would be a good idea to provide a better
       default mechanism for setting object attribute values during
       construction. Particularly attributes which are themselves objects.

  - <C>old</C>
    o  Allow to toggle support on/off for all and/or per-contract
    o  Turn off by default too much overhead copying packages and objects
    o  Reexamine implementation of <C>old</C> with attention to destructors
       and cleanup of the temporarily allocated package namespace better. 
       Worry about magic and stash de-allocation.

  - <C>private</C>: revisit and determine what to do if derived class
    tries to make its derived privates public.

  - <C>post</C>: Add support for post-conditions on objects? How? Scalars,
    arrays, and hashes are actually tied objects and do this on destruction.
    Perhaps support post conditions on objects created via Class::Contract
    by return a blessed reference to the same $key used to lookup object data
    in the lexical Class::Contract %data. And provide an object attribute
    for post-conditions that gets called by doppleganger on destruction?

  - <C>failmsg</C>: Figure out how get <C>_location</C> to provide correct
    file and line number when evals are involved.

  - Tests 
    o  Restructure and expand
    o  Check out new version of Test::Harness and see if I can drop the
       Magic.pm hack used for testing.

  - Add support for <C>friend</C> classes?


1.11    Mon Mar 05 10:31:54 2001

  - Added support for clone method which may be used as you might imagine.
    To clone an object. Like ctor you may use clon to define initialization
    pre, impl, post, and invar clauses to execute when cloning an object.

  - Fixed problem working with objects which weren't created with
    Class::Contract. Problems arose when an object wasn't a scalar reference.

  - Fixed typo in _dcopy which broke deep copying of scalar references


1.10    Sun Feb 09 12:15:31 2001

  - Added missing <C>old</C>. It was documented but not implemented

  - &self is now only way to access object/class reference. Use
    self(self->next) instead of $_[0] = $_[0]->next.

  - refactored all condition checking to use <C>generic_check</C> function

  - revisted _inheritence and generic_check. Think I've finally got
    weakening pre-conditional checks working correctly. There is a good
    test covering this in t/method.t


1.04    Wed Jan 31 15:45:42 2001

  - Begun the process of writing extensive tests. Finding and
    fixing many bugs.

  - Calling a class accessor or method with an object reference
    will now auto-magically change &self into a class name reference.
    This was documented but not implemented. The converse, calling an
    object accessor or method with a class reference causes an assertion

  - Added keyword 'private'. Methods declared private can only be
    invoked by the class or its descendants.

  - Added optional exportation of shortcuts: scalar_attrs, array_attrs,
    hash_attrs, methods. Allows defining clauses like:
    abstract methods qw( foo bar baz );

  - Fixed inheritence of pre-condition and implementation sub-clauses.
    Sub-clauses weren't always inherited when the derived class
    failed to define one.

  - Fixed pre-condition checks. Satisfying self or any ancestor
    wasn't working correctly when either the ancestor or the
    derived class did not define any preconditions.

  - &inherits now croaks on circular references in inheritence

  - Rewrote _location so we can now use eval within the
    contract statement to generate attribs, methods, etc.

  - Post conditions and invariants can no longer modify by 
    reference a method's @_. Now conditional checks receive a
    @{[@_]} shallow copy.

  - Fixed flyweight objects returned by constructor to avoid a
    dangling reference which was preventing garbage collection.

    The flyweight object is a blessed reference to $key which is
    itself a reference to an undefined lexical scalar. $key is
    also used as the hash key to the lexical %Class::Contract::data
    which stores a given object's data. Previously constructors
    returned $key. Consequently, when an object went out of scope
    in your script, %data continued to reference $key. Now, when the
    flyweight, which is not internally referenced by Class::Contract,
    goes out of scope its destructor clears $data{$key}, and Perl's
    garbage collection takes place. For a coherent explanation of 
    such issues read section 13.13 of the Perl Cookbook, 1st Edition.

  - Fixed multiple inheritence to appropriately handle cases where
    a descendant might inherit the same base class through 2 or 
    more intermediary classes. I.e. diamond patterns in inheritence
    tree. This affects inheritence of invars, attributes, methods,
    constructors, and destructors. Previously, it was possible to have
    a base class' initialization code called multiple times by a
    descendant's constructor. Once for each ancestor with the common
    base class. 

  - Fixed multiple inheritence with regard to constructor
    initialization to be left-most depth-first, instead of
    right-most depth-first. Destructors are the symetrical opposite
    right-most derived-first.


1.03  Wed Dec 27 14:06:11 2000

  - Reformatted source to new maintainer's tastes. 2 space indent
    and tabs, removal of barewords, foreach instead of for, etc.
    Otherwise no changes to the underlying code.


1.02  Fri Dec 21 10:22:48 2000

  - One line change to C<generic_precheck> to fix improper skipping 
    pre-conditional checks in some cases (thanks Jeff)


1.01  Fri Dec  9 09:52:02 2000

  - Change to generic constructor to work around magical limitations
    of overload.pm. Should now play nicer with overload.pm

  - Reversed ordering of Changes (this document)

  - Updated documentation to reflect probationary new maintainer
    C. Garrett Goebel, GGOEBEL, <ggoebel@cpan.org>


1.00  Sun Aug  6 07:11:35 2000

  - Changed semantics of preconditions.
    Now only inherited if not defined in same class
    (this conforms with the notion of derived classes
    being allowed to weaken, but not strengthen preconditions).

  - Added postconditions on SCALAR, ARRAY, and HASH attributes

  - Added &value for attr conditions

  - Removed &result -- now uses &value instead

  - Added warning when explicit preconditions in derived
    class override inherited preconditions from base class.

  - Added default ctor ('new') if none specified.

  - Modified flyweight implementation (more robust, secure, and
    efficient)

  - Modified ctors to refuse to instantiate classes with
    1+ abstract methods.

  - Added class constructors and destructors

  - Changed production code mechanism
    (now a separate, accelerated class: Class::Contract::Production)


0.05  Wed Nov 24 14:11:22 1999

  - First beta version


0.01    Fri Jul 23 14:35:54 1999

  - original version; created by h2xs 1.18
    (very much alpha)