OpenEuphoria

Re: RE: pass by reference Karl

• Posted by Derek Parnell <ddparnell at bigpond.com> Feb 12, 2002
• 488 views

kbochert at ix.netcom.com wrote:
> 
> In my implementation, pass-by reference is accomplished by
> the caller. That is:
> 
>    procedure foo (sequence x)
>       x = x[2..3]
>    end procedure
> 
>    sequence s = "test"
>    foo (s)
>    -- s still equals "test"
> 
>    foo (!!s)
>    -- s now equals "es"
> 
> Library routines can never do something behind your
> back.

I'm not so sure Karl. Lets say that I have a routine like this...

   procedure X(object a)
      if sequence(a) then
          a = ConvertToNumber(a)
      end if

      GlobalX += a
   end procedure

then I call this using your method...

   s = "23"
   X(!!s)

this should either crash with an assignment error (assigning an atom to seq) or
change the sequence
S to now be an atom.

However, calling it normally is quite safe...

   s = "23"
   X(s)

---------
Cheers,
Derek Parnell