OpenEuphoria

Re: Is subscripting a slice useful

• Posted by codepilot Gmail Account <codepilot at gmail.com> Oct 08, 2004
• 546 views

Totally correct, my foot hurts, should be {97,97}.
And I dont think I could prove that native is much faster, but would look nicer.


On Sat, 09 Oct 2004 00:17:19 +0100, Pete Lomax
<petelomax at blueyonder.co.uk> wrote:
> 
> On Fri, 8 Oct 2004 14:26:12 -0700, codepilot Gmail Account
> <codepilot at gmail.com> wrote:
> 
> >Right now subscripting a slice is not allowed.
> >
> >}}}
<eucode>
> >constant asdf={"asdf","asdf","asdf","asdf"}
> >? asdf[1..2][1]
> ></eucode>
{{{

> >I think that this code should print out {97,97,97,97}.
> 
> I think you just shot yourself in the foot )
> 
> There is *no* way that asdf[1..2] should return anything other than a
> sequence of length 2, and hence a nested subscript of that could not
> possibly yield a sequence of length 4. What, in contrast, would you
> expect asdf[1..4][1] to print? (Surely something else!)
> 
> This whole idea (which has been extensively discussed before) is so
> open to misinterpretation it should definitely NOT be "standard".
> Every application needs something different.
> 
> That said, it is not difficult. If you want to extract something from
> a complex sequence then I'll happily write a function for you, given a
> suitable example. If you wanted {97,97} then:
> 
> }}}
<eucode>
> constant asdf={"asdf","asdf","asdf","asdf"}
> 
> function subscript(object o, sequence what)
> object this
>        this=what[1]
>        what=what[2..length(what)]
>        if sequence(this) then
>                if length(this)!=2 then ?9/0 end if
>                for i=this[1] to this[2] do
>                        o[i]=subscript(o[i],what)
>                end for
>                return o[this[1]..this[2]]
>        end if
>        if length(what) then
>                return subscript(o[this],what)
>        end if
>        return o[this]
> end function
> 
> ? subscript(asdf,{{1,2},1})
> </eucode>
{{{

> 
> prints {97,97}
> 
> Let me know if this does not do exactly what you want.
> 
> Regards,
> Pete
> PS I'd be quite surprised if anyone could prove this was significantly
> slower than doing it "native". The cost is entirely in the creation of
> the new sequence (aka result); the subscripting/function calls pale
> into insignificance. CMIIW, if you can.
> 
> 
> 
> 
>