[TCLCORE] Re: TIP#176: Add String Index Values

[<dg...@us...>]

Got started trying to implement
TIP 176, and ran into a conflict
that hasn't been noted before:

    lindex $l {2 +3}

Currently, the second argument
is interpreted as a list of
indices, and the 3rd element
of the 2nd element of $l is returned,
if present.

After TIP 176, though, {2 +3} would
also match the proposed M+N syntax
for an index, and the 5th element
of $l would be returned.

Also worth noting that there was
much objection to the "end+N" notation
in the original replies to this proposal,
but that really should not be a problem.
In fact, that feature is already present
in Tcl:

% string index abc end--1
% 

That's equivalent in every way to
the proposed end+1 that got people upset.

I'm willing to move forward on this TIP,
but the ambguity above has to be sorted
out.  Ruling out trailing whitespace in
the M part of M+N would be sufficient, 
I think.  Comments?

DGP