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add clarification requests
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I'm assuming that True and False will still exist, and this is for the __bool__ special method (replacing today's __nonzero__, that is used when an arbitrary object is tested for true/false). | I'm assuming that True and False will still exist, and this question is really about the __bool__ special method (replacing today's __nonzero__), that is used when an arbitrary object is tested for true/false. |
Possible Python 3K Class Tree?
This page contain an incomplete thinking-out-loud description of a re-factoring of the base and built-in Python types into a set of Abstract Base Classes (ABCs) and concrete types. This would probably be a good time to enumerate the exceptions various basic operations can raise, as well.
Some questions:
How to handle optional parameters, such as in the "sort" method on MutableSequence?
Do you mean optional methods (a deque may not be appropriate for sorting)? Or are you talking about parameters on methods (such as the "key" keyword of most sort methods)?
Should Boolean be an abstract type that's mixed-in to Object, or a concrete type that inherits from Object (thus implying that non-Boolean Objects may exist)?
I'm assuming that True and False will still exist, and this question is really about the bool special method (replacing today's nonzero), that is used when an arbitrary object is tested for true/false.
Should destructive operations on MutableSequence return the sequence? They don't currently, but this would be very useful. I've made it so in this list...
In Py2, Boolean is a sub-type of Integer. Does this make sense? I've made it its own type in this list...
Should None just be an instance of Object? Does NoneType need to exist?
- If a file is opened in binary mode, should its iterator be over bytes instead of lines? Should "readline()" even work on a binary file?
Comparable: equals (Comparable) => Boolean Object (Comparable): hash () => Integer # presumable for "is" we compare the ids of the two objects id () => Integer true () => Boolean # the __str__ method printable () => String class () => Type implements (Type) => Boolean Type (Object): name () => String # supertypes yields list of immediate parent types (what's in __bases__) supertypes () => Sequence # interfaces yields flattened list of all interface types this implements interfaces () => Sequence Ellipsis (Object): # contains only the single value represented by three dots ThreeDots Null (Object): # only a single value of this type None Exception (Object): args () => Sequence ExceptionContext (Object): exception () => Exception traceback () => Traceback Boolean (Object): True False Orderable: less_than (Object) => Boolean greater_than (Object) => Boolean Numeric: add (Numeric) => Numeric subtract (Numeric) => Numeric product (Numeric) => Numeric quotient (Numeric) => Numeric floored_quotient (Numeric) => Numeric remainder (Numeric) => Numeric negate (Numeric) => Numeric absolute_value () => Numeric exponentiate (Numeric) => Numeric magnitude () => Numeric Integer (Object, Orderable, Numeric): or (Integer) => Integer xor (Integer) => Integer and (Integer) => Integer shift (Integer) => Integer invert (Integer) => Integer real () => Real Real (Object, Orderable, Numeric): floor () => Integer ceiling () => Integer Complex (Object, Orderable, Numeric): conjugate () => Complex Decimal (Object, Orderable, Numeric): TBD Iterable: iterator () => Iteration Iteration (Object, Iterable): next () => other KeyValueIterable (Iterable): # yields iteration of key-value pairs # should Container be Iterable, or should that be reserved for real types, like Tuple? Container (Iterable): len () => Integer contains (Object) => Boolean Set (Container): is_subset (Set) => Boolean is_superset (Set) => Boolean union_with (Set) => Set intersection_with (Set) => Set difference (Set) => Set symmetric_difference (Set) => Set # should this be "multiply" to match Sequence? shallow_copy () => Set Sequence (Container): contains (Sequence) => Sequence # normal access via index slice1 (Integer) => Object # normal slice of range slice2 (Integer, Integer) => Sequence # slice with step K slice3 (Integer, Integer, Integer) => Sequence # return self + other Sequence concatenate (Sequence) => Sequence # N shallow copies of self multiply (Integer) => Sequence # do "min" and "max" make sense over arbitrary sequences? Should really only apply to sequences of "Orderable" min () => Object max () => Object MutableSequence (Sequence): append (Object) => self insert (Integer position, Object) => self # value at I is replaced with Object replace (Integer position, Object) => self # slice from I to J is replaced with values of Iterator replace2 (Integer start, Integer end, Iterable) => self # slice from I to J with step K is replaced by Iterator replace3 (Integer start, Integer end, Integer step, Iterable) => self extend (Object) => self count (Object) => Integer reverse () index1 (Object) => Integer index2 (Object, Integer start, Integer end) => Object pop1 () => Object pop2 (Integer position) => Object delete1 (Integer position) => self delete2 (Integer start, Integer end) => self delete3 (Integer start, Integer end, Integer step) => self sort0 () => self sort1 (Function comparison_fn) => self sort2 (Function comparison_fn, Function key_fn) => self sort3 (Function comparison_fn, Function key_fn, Boolean reverse) => self ByteSequence (Object, Sequence): # should this be a MutableSequence? Buffer (Object, MutableSequence): # is this just mutable version of ByteSequence? String (Object, Sequence): TBD Tuple (Object, Sequence): List (Object, MutableSequence): Mapping: get (Object key) => Object get_with_default (Object key, Object default) => Object set (Object key, Object value) # should delete return the deleted value? Why not. That removes the need for "pop". delete (Object key) => Object clear () copy () => Mapping contains (Object key) => Boolean # items returns a value which is guaranteed to satisfy both the Set interface and the KeyValueIterable interface items () => (Set and KeyValueIterable) keys () => Set values () => Set # get_or_set is the current "setdefault" get_or_set (Object key, Object value) => Object update (Mapping) => self # alternate form of "update" takes Iterable of key-value pairs update (KeyValueIterable) => self # do we really need fromkeys? fromkeys (Sequence keys, Object initial_value) => Mapping Dict (Object, Mapping, Container): # should some methods (e.g., "fromkeys") be here instead of in Mapping? ExecutionContext: enter () => ExecutionContext exit (ExceptionContext) => Boolean Stream: close () flush () read () => ByteSequence read (Integer) => ByteSequence write (ByteSequence) => Integer RandomAccessStream (Stream): # do we really need to continue to mimic the low-level UNIX seek and tell? # why not use Python sequence-style indices for offset? seek (Integer offset) tell () => Integer TextStream (Stream): readline () => String readlines () => Sequence writeline (String) => Boolean writelines (Sequence) => Boolean encoding () => String OpenFile (RandomAccessStream): # it would be great if this had a "mimetype" method fileno () => Integer filename () => String isatty () => Boolean truncate (Integer size) mode () => String BinaryOpenFile (Object, Stream, OpenFile, Iterable, ExecutionContext): TextOpenFile (Object, TextStream, OpenFile, Iterable, ExecutionContext):