Issue #9049 has been updated by boris_stitnicky (Boris Stitnicky).


@david_macmahon: I do not think that the wish to make a : b an alias of a .. b
can fit into the language anymore. "x > 0 ? 1 : 2 : 3" could be ambiguously
parsed as "x > 0 ? ( 1 : 2 ) : 3" or as "x > 0 ? 1 : ( 2 : 3 )"...

    
----------------------------------------
Feature #9049: Shorthands (a:b, *) for inclusive indexing
https://bugs.ruby-lang.org/issues/9049#change-42592

Author: mohawkjohn (John Woods)
Status: Open
Priority: Low
Assignee: 
Category: core
Target version: 


=begin
For NMatrix, we've implemented a range shorthand which relies on Hashes: (({m[1=>3,2=>4]})), for example, which returns rows 1 through 3 inclusive of columns 2 through 4 (also inclusive). The original goal was to be able to do (({m[1:3,2:4]})) using the new hash notation, but the new hash notation requires that the key be a symbol ??? it won't accept an integer.

Whether through the hash interface or not, it'd be lovely if there were a shorthand for slicing matrices (and even Ruby Arrays) using colon. This could just be an alternate syntax for ranges, also ??? which might make more sense.

The other related shorthand we'd love to find a way to implement is the all-inclusive shorthand. It gets to be a pain to type (({n[0...n.shape[0],1...3]})) to get a submatrix (a slice), and it's really difficult to read. As a work-around, we currently use the (({:*})) symbol: (({n[:*,1...3]})). But it'd be simpler if there were a way to use a splat operator without an operand as a function argument. It might be a special case where the (({*})) is treated as a (({:*})) automatically. But this edge case might cause confusion with error messages when users make syntax errors elsewhere.

The colon shorthand is the highest priority for us.
=end



-- 
http://bugs.ruby-lang.org/