OpenEuphoria

Re: Re[2]: (Another) (small) Eu 2.5 feature request.

• Posted by Derek Parnell <ddparnell at bigpond.com> Sep 23, 2004
• 464 views

irv mullins wrote:
> 
> unknown wrote:
> > 
> > >> Can cause ambiguity.. although it is nice looking
> > >> 
> > >> what does a.b.2 mean? a[b][2] or a[b[2]] ?
> > >> 
> > W> a[b][2]
> > W> however since you brought it up,
> > W> a.b..2
> > W> could mean
> > W> a[b[2]]
> > 
> > a.b..2 can also mean a[b..2]
> > 
> > hehehe :D
> > better use another syntax?
> 
> Here you see the reason subscripted sequences are not a substitute 
> for real structures. Even though structures would make Euphoria 
> code safer and clearer ...

And slower. 

Assuming of course that a struct is a vector that cannot change its length,
that each element is given a name, and each element's datatype is set
at definition time.

Slower because there would be three fundamental changes to
the inner interpreter. It would have to support the idea of fixed-length
sequences, the idea of fixed-datatype sequence elements, and a new
scope level - that of sequence, as element positions would have names
as well as numeric indexes.

I imagine your are hoping for something like ...

struct customer
  sequence PersonalName
  sequence FamilyName
  sequence Address
  integer ZIPcode
  integer CustNumber
end struct

customer CurrentCust

CurrentCust.PersonalName = "Derek"
CurrentCust.FamilyName = "Parnell"
CurrentCust.CustNumber = newnumb()

In which case, the interpreter would need to add extra checks to
append(), prepend(), &, slicing and assignment to make sure it was
not changing the target's length, or datatypes. 

I agree that this could make for safer and clearer code, but at the cost
of execution speed. Some people get a bit worried about that aspect.

-- 
Derek Parnell
Melbourne, Australia