[EMAIL PROTECTED] wrote: > Hello, > > Terry Reedy wrote: > >>So I do not see any point or usefulness in saying that a tuple subcript is >>not what it is. > > > I know that a tuple is *constructed*. The question is, is this, > conceptually, the feature that allows you to ommit the parentheses of a > tuple in some cases. If we see this as the same feature, it's > reasonable that "nothing" won't be seen as an empty tuple, just like "a > = " doesn't mean "a = ()". > > However, if we see this as a different feature, which allows > multidimensional subscript by constructing a tuple behind the scenes, > constructing an empty tuple for x[] seems very reasonable to me. Since > in some cases you can't have the parentheses at all, I think that x[] > makes sense. > Hey, I have an idea, why don't we look at the language reference manual instead of imagining how we think it might work!
In section 3.2 we find: """ Tuples The items of a tuple are arbitrary Python objects. Tuples of two or more items are formed by comma-separated lists of expressions. A tuple of one item (a `singleton') can be formed by affixing a comma to an expression (an expression by itself does not create a tuple, since parentheses must be usable for grouping of expressions). An empty tuple can be formed by an empty pair of parentheses. """ So it seems that your speculation is false. Section 2.6 specifically defines "[" and "]" as delimiters. Section 5.3.2 defines a subscription (a term I've not really grown to love, but what the heck) as subscription ::= primary "[" expression_list "]" and section 5.12, which defines expression_list, explicitly says """An expression list containing at least one comma yields a tuple.""". So it would appear that while your change might be very convenient to allow you to refer to scalar values as zero-dimensional arrays, it doesn't really fit into Python's conceptual framework. Sorry. One further point: if you really do conceptualize scalars as zero-dimensional arrays, where is the value conceptually stored? regards Steve -- Steve Holden +44 150 684 7255 +1 800 494 3119 Holden Web LLC/Ltd http://www.holdenweb.com Love me, love my blog http://holdenweb.blogspot.com Recent Ramblings http://del.icio.us/steve.holden -- http://mail.python.org/mailman/listinfo/python-list
