OpenEuphoria

1. Namespace

• Posted by dcole Jun 19, 2010
• 1956 views

Hello Everybody,

Namespace, What is it? What is it used for? Where can I see examples? Where is it documented?

Don Cole

3. Re: Namespace

• Posted by DerekParnell (admin) Jun 19, 2010
• 1960 views

The namespace concept was created to get around a common problem with Eu v3.

When two independently created libraries both expose the same symbol name, how does your program, when it includes both libraries, know which name you are referring to in your code?

For example...

-- LIBRARY A -- 
global integer theXvalue = 'x' 

-- LIBRARY B -- 
global sequence theXvalue = "X" 

--- Your App ---- 
include lib_A.e 
include lib_B.e 
 
theXvalue = someFunc() 

The problem is, when your code runs, it doesn't know which theXvalue you want to set. Is it the one in Library A or Library B?

In this situation you can use namespaces to help you tell Euphoria which to use.

--- Your App ---- 
include lib_A.e as libA 
include lib_B.e as libB 
 
libA:theXvalue = someFunc() 
if find(libB:theXvalue, libA:theXvalue) then ... 

As you can see, you can explicitly disambiguate your code by telling Euphoria which exposed symbol you need to use.

It is documented in section "4.8.1 include" of the documentation.

5. Re: Namespace

• Posted by dcole Jun 19, 2010
• 1932 views

Thank you Signor and Derek,

Signor: I read all of it. Manual 1 Section 2 was especially enlightening.

Derek: I guess it's the as that makes it a namespace. It's in "4.8.1 include" of what document?

Don Cole

7. Re: Namespace

• Posted by SPringle Jun 19, 2010
• 1922 views

Namespaces also gives you data encapsulation.

A Euphoria program could start like this:

include sets_simple.e as person_set 
include sets_simple.e as inventory_set 
include sets_binary.e as receipt_set 

If you always use the namespaces, you can shift from one implementation to another simply by changing the included filenames named in the file. This works as long as the identifiers are present in all of the implementations and implement the same thing.

Shawn

9. Re: Namespace

• Posted by SPringle Jun 21, 2010
• 1815 views

The problem you outlined will simply not be if the modules consist of routines that only use what you pass into them, such as using new() and is_match() from wildcard or from regex.

Shawn Pringle