OpenEuphoria

Re: . or : for namespace?

• Posted by Mike <vulcan at win.c?.n?> May 06, 2008
• 676 views

CChris wrote:
> 
> Mike wrote:
> > 
-- snip
> > Now, here is an example of how silly it can get:
> > 
> > include file.x as b
> > sequence a
> > ..
> > 
> > a.b.c
> > 
> > What does this mean? it really means <drum roll>  a . b:c
> > 
> >   !GASP!
> > 
> > If the dot is used for namespaces, sequence access, also using dots, will be
> > fraught
> > with such perils.
> > 
> > If there is to be *any* hope of using dot notation generally, I would really
> > love to
> > see someone try and explain away the above example.
> > 
> > I am sure there will be people who would prefer to use . as namespace but
> > they
> > would also
> > like to use . for sequence access. Insisting on the former will jeopardize
> > the
> > latter.
> > 
> > or am I mistaken about this?
> > 
> > 
> > regards,
> > Mike
> 
> I'm not getting your point.
> 
> A namespace delineates a chunk of code (currently, that must be an entire file
> (sigh)) in which some identifiers are.
> In structured access for sequence, the structure type delineates a chunk of
> code (the field list declaration) in which some identifiers are.
> 
> Why does the difference matter?
> 
> CChris

It potentially attracts major obsfucation, eg:

a.b.c.d could mean..

a[b][c][d]  or  a:b[c][d] or  a[b:c][d]  or  a[b][c:d]  or a:b[c:d]

It is true that, technically, such a system could work because the compiler has
enough info to figure it all out. But, we're not machines.

This example assumes that we are accessing Euphoria sequences and that we really
want to have the freedom to put namespace references anywhere in the dot-chain,
not just a single one right at the head of the dot-chain. And even then,
ambiguity
remains, eg..

a.b.c.d could mean..

a[b][c][d]  or  a:b[c][d]


However, things appear less problematic for future genuine (C) structures,
because,
as you point out, the field declarations are specified. Nevertheless, there may
be
instances where it would be useful to mix structure fields and normal variables
(which may include namespaced references) along the same dot-chain. Some
structures
contain arrays. Wouldn't it great to be able to iterate over such a thing using
a
for loop? Eg:

struct complex
  double real
  double img
end struct

struct any
  list complex[256]
end struct

any ptr = address()

for i = 1 to 256 do
   ptr.i.real = whatever_real()
   ptr.i.img = 0.0
end for


So, basically we have :

obsfucation OR lack of freedom + nice looking 

vs

clarity + freedom - looks


(the freedom referred to is a future freedom affected by design decisions being
made now)

regards,
Mike

PS: I hope my examples are clear enough