OpenEuphoria

Att: Rob - namespace problem

• Posted by Hayden McKay <hmck1 at dodo.com.au> Sep 22, 2005
• 471 views

There seems to be some "namespace" abnormality under some rare circumstances.

1. I'll demonstrate what I was tryeng to do.
2. I'll demonstrate a hack I found to fix it.

I found this problem while codeing a new bst class for an application.
An extract from the library is something like this...

-- bst.e

constant
    --
    bstNdata = 1,
    bstLeafL = 2,
    bstLeafR = 3

type node(sequence s) return length(s) = 3 end type

sequence bstTree bstTree = {}

global function bstLookup(atom n) -- lookup at bstTree
global function bstInsert(atom n) -- insert at bstTree
-- etc...

Ok. Now I wanted to use multiple Binary Serch Tree's and the easiest way to
do this was to exploit Euphoria's namespace qualifier to create two classes.

-- Too make two instaces of "bstTree" (in bst.e) I did the syntax...

include bst.e as BinaryTableOne
include bst.e as BinaryTableTwo

BinaryTableOne:bstInsert(1)  -- Insert to 1st bstTree Inctance
BinaryTableTwo:bstInsert(2)  -- Insert to 2nd bstTree Inctance

This did not work! Only one instace of "bstTree" existed?  However a valid
work around was to have two copies of the file with two different names ie

include bstOne.e as BinaryTableOne
include bstTwo.e as BinaryTableTwo

BinaryTableOne:bstInsert(1)  -- Insert at 1st bstTree Inctance
BinaryTableTwo:bstInsert(2)  -- Insert at 2nd bstTree Inctance

And presto... it worked!  The drawback is that I need to have multiple copies
of the same bst.e file accompany the source. Maybee this issue could be fixed
in a future release.

Note: The other alterative was to have a function return a handle. And have
      "bstTree" store multiple trees.