OpenEuphoria

Re: Namespace request

• Posted by Al Getz <Xaxo at aol.com> Feb 11, 2006
• 493 views

Jason Gade wrote:
> 
> Al Getz wrote:
> > 
> > Jason Gade wrote:
> > > 
> > > Rob, can you change namespacing so that more than one file can be included
> > > into
> > > the same namespace?
> > > 
> > > Here is an example of what I want to do:
> > > 
> > > include misc.e as rds
> > > include machine.e as rds
> > > include dll.e as rds
> > > 
> > > Currently the interpreter gives an error.
> > > 
> > > Rationale: I want to use namespaces in a file that is intended to be
> > > included
> > > by another so as to avoid conflicts in user programs. But when I know that
> > > there
> > > will be no conflicts within the files that I'm including I don't want to
> > > make
> > > a new namespace for every single include. This will also help prevent
> > > namespace
> > > pollution by reducing the number of unique namespaces that a program needs
> > > to
> > > come up with.
> > 
> > Hi there,
> > 
> > 
> > So i guess you're saying you want to include multiple files under the
> > same namespace so functions can be called in multiple files using
> > the same prefix...interesting...
> 
> Yes. That's the way it works in C++, several related includes are part of the
> same namespace. C++ also has the 'using namespace' keyword.
> 
> But right now I'm looking through the listserv archives to understand better
> how namespace rules actually work. I've noticed so far that they don't exactly
> do what I think they do.
> 
> So far I've found that using namespaces within a library won't prevent symbol
> conflicts in user programs, though using them might make them easier to fix.
> The user program will still have to use a namespace when a conflict arises.
> 
> By my example, I don't really expect there to be a symbol conflict with RDS
> libs, but I was trying to be "future proof" and protect the user from having
> to worry about it.
> 
> --
> "Any programming problem can be solved by adding a level of indirection."
> --anonymous
> "Any performance problem can be solved by removing a level of indirection."
> --M. Haertel
> j.

Hi again,

I guess there are good points to this and bad points, but i havent
thought it all through myself yet.
I wanted to be able to include the same file more than once (which
would be easy in the source code) and have it load again so that 
local variables get repeated:

--Start Manager.ew
  atom a
  global procedure LoadA(atom x)
    a=x
  end procedure
  global function GetA()
    return a
  end function
--End Manager.ew

  include Manager.ew as M1
  include Manager.ew as M2

  M1:LoadA(10)
  M2:LoadA(20)

  ?M1:GetA() --prints "10"
  ?M2:GetA() --prints "20"

Currently, you have to copy and rename Manager.ew and included it a second
time with it's new name
  include Manager1.ew as M1
  include Manager2.ew as M2

If we could include the same file twice and get a new instance loaded
(as per code far above) we would be able to handle files as entire
objects, which would increase the functionality of Euphoria quite a bit.
Imagine being able to write a 'class' file as an include file that had
all kinds of functionality including functions AND data structures,
and in one line be able to repeat that 'object' 
  include MyClass.ew as Class1
  include MyClass.ew as Class2

Add to that the ability to index and WOW we've got incredible functionality:
  Class={1,2,3,4,5}
  for k=1 to 5 do
    include MyClass.ew as Class[k]
  end for
and suddenly we can index entire classes:
  data1=Class[1]:data
  data2=Class[2]:data
  etc.

WOW!!!!!!!!


Take care,
Al

And, good luck with your Euphoria programming!

My bumper sticker: "I brake for LED's"