OpenEuphoria

RE: listed subscripting

• Posted by Cuvier Christian <christian.cuvier at insee.fr> Apr 24, 2006
• 500 views

> Subject: Re: listed subscripting
> 
> 
> posted by: ags <eu at 531pi.co.nz>
> 
> Antonio Alessi wrote:
> > An expression like:
> > }}}
<eucode>
> > newString- = 
> originalString[1..2]&"INSERT"&originalString[5..9]&originalStr
> ing[27..$]
> > </eucode>
{{{

> > could simply become:
> > }}}
<eucode>
> > newString- = originalString[1..2]&"INSERT"&[5..9]&[27..$]
> > </eucode>
{{{

> > It should be plain to implement, I mean more useful than 
> complicated...
> 
> I don't think that would work very well.  What if you wanted 
> to use multiple strings like:
> 
> }}}
<eucode>
> newString = originalString[1..2] & "INSERT" & 
> otherString[3..5] & [5..9]
> </eucode>
{{{

> What would the "[5..9]" refer to?
> 
> I like the idea of listed subscripts though.  It would only 
> be useful IMHO if it worked with predefined sequences like:
> 
> }}}
<eucode>
> constant REPORT_FIELDS = {1,5,9,13}
> 
> sequence item
> 
> --in some for loop
>     item = record[REPORT_FIELDS]
> </eucode>
{{{

> 
> That changes the semantics codepilot originally brought up though, ie:
> 
> variable[1,5,9,13]
> 
> does not look the same as
> 
> variable[{1,5,8,13}]
> 
> and Al Getz wrote:
> > I've had my share of problems like this too, where you could use
> > some sort of functionality to deal with sequences easier.
> > Another that comes immediately to mind is
> >   {a,b,c,d}=s[1,2,3,4]
> 
> I think Rob has already made his views clear on multiple 
> lvalue assignment and I tend to think it would be a headache 
> in the context of Euphoria.
> 
> What happens (even in the case of a subscript list) if the 
> sequence s is not as long as the subscript list?
> 
> Gary
> 

Perhaps a cleaner syntax would be to mention the insert explicitly rather
than through the use of & when only one sequence is involved, using & when
really concatenating different things:

newString=insert(originalString[1..2,5..9,27..$],"INSERT",3)
--but
newString=originalString[1..2]&"INSERT"&otherString[5..9,27..$]

And of course, it is a real pain not to be able to write:

function doSomething(sequence vars)
--...
end function

procedure whatEver()
integer n1,n2
sequence s1,s2,s3
--...
{n1,n2,s1,s2,s3}=doSomething({n1,n2,s1,s2,s3})
--...
end procedure

The above code would allow to write a separate routine for what doSomething
does, avoiding the error prone, tiresome, cluttered, unelegant urrent
solution:

vars=doSomething({n1,n2,s1,s2,s3})
n1=vars[1]
s1=vars[3]
--etc

Rob, when will you decide to make Euphoria simple to use???

CChris