on slices, negative indices, which are the equivalent procedures?

[Hope Rouselle]

Hope Rouselle <hrouselle at jevedi.com> writes:

> Hope Rouselle <hrouselle at jevedi.com> writes:
>
>> Dennis Lee Bieber <wlfraed at ix.netcom.com> writes:
>>
>>> On Sun, 15 Aug 2021 00:05:29 -0300, Jack Brandom <jbrandom at example.com>
>>> declaimed the following:
>>>
>>>>Dennis Lee Bieber <wlfraed at ix.netcom.com> writes:
>>>>
>>>
>>>>> subscript: '.' '.' '.' | test | [test] ':' [test] [sliceop]
>>>>> sliceop: ':' [test]
>>>
>>>>
>>>>This is looking less readable, so, no, I prefer that previous, which was
>>>>much clearer about slices.  I can't even quite make the slices out in
>>>>these rules.  (But thanks for the opportunity to try.)
>>>
>>> 	The last part of "subscript" has the main "slice" notation (stripping
>>> the quotes)
>>>
>>> 		[test] : [test]
>>>
>>> and the "stride" component is [sliceop] being
>>>
>>> 		: [test]
>>
>> Let's see.  Let ``-->'' mean ``expands to''.  Then
>>
>>       subscript 
>>   --> [test] ':' [test] [sliceop]
>>   --> [test] ':' [test] ':' [test]
>>
>> Does the brackets mean that its content count be omitted?
>   ^^^^                                    ^^^^^
>
> _Do_ the brackets mean that its content _can_ be omitted?  (This is
                              ^^^
> really too much coffee.  It's crazy where my attention goes.)

Lol.  Should I say _their_ content?  I guess so. :-)