Am 23.05.18 um 07:22 schrieb Chris Angelico:
On Wed, May 23, 2018 at 9:51 AM, bartc <b...@freeuk.com> wrote:
Sorry, but I don't think you're right at all. unless the official references
for the language specifically say that commas are primarily for constructing
tuples, and all other uses are exceptions to that rule.
"A tuple consists of a number of values separated by commas"
https://docs.python.org/3/tutorial/datastructures.html#tuples-and-sequences
"Separating items with commas"
https://docs.python.org/3/library/stdtypes.html#tuple
"Note that tuples are not formed by the parentheses, but rather by use
of the comma operator."
https://docs.python.org/3/reference/expressions.html#parenthesized-forms
Enough examples? Commas make tuples, unless context specifies otherwise.
I'd think that the definitive answer is in the grammar, because that is
what is used to build the Python parser:
https://docs.python.org/3/reference/grammar.html
Actually, I'm a bit surprised that tuple, list etc. does not appear
there as a non-terminal. It is a bit hard to find, and it seems that
"atom:" is the starting point for parsing tuples, lists etc.
Christian
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