OpenEuphoria

Re: Is subscripting a slice useful

• Posted by Derek Parnell <ddparnell at bigpond.com> Oct 14, 2004
• 552 views

Pete Lomax wrote:

[snip]

> This is all possible, but you should at least by now understand why
> *I* don't consider it an improvement to the lovely, elegant language
> we all know and love.
> 
> If the majority want this, so be it, I've had my say.

I must agree with Pete (a rare thing I suspect). The concept of 'vertical'
slicing needs a new syntax altogether, if we need to have it at all in 
the language. 

Currently the "[n..m]" notation in an expression is saying ...

"create a new sequence, and build it from elements 'n' to 'm' inclusively"

But vertical slicing implies that we don't want to use all of each element
but just a subset of each element. So the difference in semantics 
(sub-element verses full element) needs to be reflected in the syntax.
Something like "[n..m : x..y]" maybe. This is saying - build a new 
sequence from elements 'n' to 'm', but for each element just use
sub-elements 'x' to 'y'. In other words, the syntax "[n..m]" could
be thought of as shorthand for "[n..m:1..$]" 

 A = { {1,2,3}, {4,5,6}, {7,8,9}, {10,11,12} }

 Thus A[2..3 : 2] would give {5,8}
  and A[2..3 : 2..3] would give {{5,6}, {8,9}}

-- 
Derek Parnell
Melbourne, Australia