OpenEuphoria

Re: [RC] Lucius tries to use namespace

• Posted by irvm at ellijay.com Jun 25, 2003
• 415 views

Lucius, in all his subtlety, is just saying what anyone who has taken a 
close look at 'namespaces' must be thinking.

I had hoped that Rob would come up with a brilliant, (and perhaps uexpected) 
solution to the namespace problem. He sometimes does that sort of thing.
What we got instead was more like a band-aid for a broken leg - 
while it might be needed, it's also completely inadequate.

The problem is not, however, as Lucius stated: that you must prefix each 
namespaced variable/function. That is a minor annoyance, and would have 
been even less of a problem if Rob had listened to the numerous suggestions 
that he implement something along the lines of Pascal's 'with .... do' 
statement. 

The real problem is that namespacing is braindead. 

Let's look at a real-life example:
In GTK, there are many controls which have similarly but logically named 
functions, for example: get_text(). Some of these functions take different 
parameters than others. 

To write a program using GTK, I have a choice:

Option 1:
I can specifically 'include ... as ..." each individual GTK control from its 
own Eu include file. That makes 124 lines of "include ... as" at the 
top of each program for any program which uses more than a few 
controls. Get real - this entre post is only about 100 lines long. 
Do you really want that much prelude to each of your programs?

Option 2:
I could write a wrapper for all these includes, and just put a single line: 
"include wrapper"
at the top of each new program.  A much better solution, right? 

Wrong. **
While in the wrapper, each include has its own identity 
(the name I chose when "including .. as"). For example: 
include entry.e as entry
include textbox.e as textbox

This eliminates name collisions inside the wrapper, because I can 
refer to "entry:set_text()" or "textbox:set_text()".

But what happens when I try to access these functions from my main 
program (the one which just 'include(s) wrapper') ?
I get an error message telling me that:
A namespace qualifier is needed to resolve set_text.
set_text is defined as a global symbol in:
    entry.e
    textbox.e
    textedit.e
    label.e
    button.e ....etc

So Euphoria knows there are several versions of "set_text()" out there,
and even which files they are found in, even though I did not specifically
"include" ANY of those files in my main program. Cool.

So I'll just qualify the function, right? 
entry:set_text("Hello World")

Wrong again!
entry has not been declared.

How does Eu know where all these "set_text()" functions are located?
It got that info from the "wrapper", where they _were_ included, obviously.

---------------
Q: If Eu can pass on the names of included files, as 
well as the names of all the globals in those files, why can't it also 
pass on the namespace qualifiers given to those files?

Ans: Braindead.
---------------

OK, Rob will say namespacing wasn't designed for that purpose, but 
only to make it easier to include libraries written by other people.
Perhaps he will explain how using a library from someone else 
differs from using the identical library written by oneself.

** note:  I managed to work around that problem, but the solution sure 
didn't involve using namespaces. It would have been *much* simpler if 
proper namespacing had been implemented.

Irv