OpenEuphoria

RE: Possible feature for new Euphoria-version

• Posted by Andy Serpa <ac at onehorseshy.com> Jan 09, 2004
• 412 views

Robert Craig wrote:
> 
> 
> Tommy Carlier wrote:
> > sequence seq
> > seq = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}
> > sequence b
> > b = {2, 2}
> > integer a
> > a = seq[b]
> > 
> > This way you can also pass and return multiple indices to and from 
> > procedures and functions.
> 
> There are at least three logical ways that you might define
> subscripting of a sequence with a sequence.
> 
> 1. Your way (above). The sequence used as a subscript would
>     contain a series of subscripts to be applied. This
>     fills a logical gap in subscripting, since currently
>     the number of levels of subscripting is fixed at
>     compile-time. You could use this for reading and writing.
> 
> 2. sequence s
>     s = {100, 200, 300, 400, 500}
>     s[{1,5,3}] is {100, 500, 300}
>     The subscript would let you randomly select a bunch of
>     elements for reading or writing.
> 
> 3. sequence s
>     s[1] = 7
>     s["Tommy"] = 99
>     s["Carlier"] = 0
>     s["Carlier"] += 1
>     ? s["Tommy"] * s["Carlier"]
> 
>     The Euphoria implementer might set up a hash table internally.
>     Whenever you assigned to a previously nonexistent
>     element, the implementation would create a new
>     element for you. This would be good for symbol tables,
>     databases etc.
> 
> Which approach is best? If you choose one, you'll
> eliminate the possibility of doing the others.
> 

Can't #1 and #2 be combined?

sequence s

s = {{1,2,3},{4,5,6},{7,8,9}}

object x


-- Like #2

x = s[{1,3}]

-- Now x = {{1,2,3},{7,8,9}}

x = s[{1,2}]

-- Same as x = s[1..2], x = {{1,2,3},{4,5,6}}

-- Like #1

x = s[{{1,2}}]

-- Now x = 2, depth of subscripting sequence = depth of retrieved 
element


-- Like #1 & #2 both

x = s[{{1,2},{3,1}}]

-- Now x = {2,7}

x = s[{{1,2},3}]

-- Now x = {2,{7,8,9}}


Logical, consistent, no?