Allow "$_[-1]", which would indicate the last element of the array Make "$x[*]" equal to listing out the full contents of "x"I think these would be pretty useful, especially for the "$_" variable, which gets the last argument of the last command, but if you give it an index like "$_[N]", gets the Nth argument of the last command. However, it's not as easy to get the second-to-last argument of the last command, or to get *all* arguments of the last command. So the above two suggestions would be pretty helpful.
Attached is a patch to do this. For the second suggestion, I took some liberties and added range syntax, so that "$x[2..5]" returns elements 2, 3, and 4 (zero-indexed) of x.
I have just one question though: this implementation treats ranges as half-open, i.e. "M..N" is [M, N). I think that's the best way of doing things (and it matches how 'seq-subseq' works). However, "M..N" is the Bash syntax, which uses a closed range, [M, N]. Maybe this would be too confusing for users? I'm open to using other tokens aside from ".." if that would help. Maybe "M:N" would work? That's the Python syntax, which behaves the same way as this patch. Any thoughts?
0001-Add-support-for-negative-indices-and-index-ranges-in.patch
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