Antoon Pardon wrote: > Op 2005-08-30, Robert Kern schreef <[EMAIL PROTECTED]>: > >>Bryan Olson wrote: >> >>> Currently, user-defined classes can implement Python >>> subscripting and slicing without implementing Python's len() >>> function. In our proposal, the '$' symbol stands for the >>> sequence's length, so classes must be able to report their >>> length in order for $ to work within their slices and >>> indexes. >>> >>> Specifically, to support new-style slicing, a class that >>> accepts index or slice arguments to any of: >>> >>> __getitem__ >>> __setitem__ >>> __delitem__ >>> __getslice__ >>> __setslice__ >>> __delslice__ >>> >>> must also consistently implement: >>> >>> __len__ >>> >>> Sane programmers already follow this rule. >> >>Incorrect. Some sane programmers have multiple dimensions they need to >>index. > > I don't see how that contradicts Bryan's statement. > >> from Numeric import * >> A = array([[0, 1], [2, 3], [4, 5]]) >> A[$-1, $-1] >> >>The result of len(A) has nothing to do with the second $. > > But that is irrelevant to the fact wether or not sane > programmes follow Bryan's stated rule. That the second > $ has nothing to do with len(A), doesn't contradict > __len__ has to be implemented nor that sane programers > already do.
Except that the *consistent* implementation is supposed to support the interpretation of $. It clearly can't for multiple dimensions. -- Robert Kern [EMAIL PROTECTED] "In the fields of hell where the grass grows high Are the graves of dreams allowed to die." -- Richard Harter -- http://mail.python.org/mailman/listinfo/python-list
