= Use Directive =

{{{
use <namespace>
use <namespace> from <library-name>
}}}

Specify a namespace whose contents are made available to this module.

When using the first form if the compiler cannot immediately locate the namespace,[[BR]]
i.e if its not in the default loaded libraries,[[BR]]
it will look for a (platform dependent) library-name of the same form as 
the namespace.


If the filename of the library differs from the namespace, you can specify 
it with the second form.[[BR]]
 
<library-name> can be a simple identifier, qualified identifier (Foo.Bar) 
or a string literal.

{{{
#!cobra
use Foo.Bar from SomeLib
}}}
You can put single or double quotes around the file name if its components 
are not legal identifiers [[BR]]
(for example, the filename has a space or punctuation mark in it).
{{{
#!cobra
use Foo.Bar from "My Lib"
}}}


== Platform ==
'''For .Net''':
There are assumed five implicit "use" directives at the top of a Cobra program:
{{{
#!cobra
use System
use System.Collections.Generic
use System.IO
use System.Text
use Cobra.Core
}}}
This gives default access to the core of the .Net objects and the cobra 
runtime Library, !CobraCore. 

These correspond to access to the following default loaded libraries
{{{
mscorlib.dll
System.dll
Cobra.Core.dll
}}}

On .Net <library-name> will refer to a .Net Assembly or dll[[BR]]

No ".dll" extension is expected (or allowed) in any of the above syntax.
  
The library name is the namespace with ".dll" appended 
e.g
{{{
#!cobra
use Foo.Bar 
# On .Net will look for the namespace in file Foo.Bar.dll if it is not already available
}}}

'''For Java''':
The namespace names specified refer to java package names (first (caps) letter downcased).

Similarly the assumed implicit directives are 
{{{
use Java.Lang
use Java.Io
use Java.Util
use Java.Text
use Cobra.Core
}}}
which correspond to the most common core java library packages (i.e java.{lang,io,util,text}) and the (java ) cobra runtime library.
(These core library packages are read from the standard java runtime system jarfile rt.jar).

The <library-name> refers to a Java jar file (no .jar extension is expected or allowed).

The jarfile name is the namespace with ".jar" appended searched for in the places given by the CLASSPATH env variable.


== Examples ==

{{{
#!cobra
use System.Windows.Forms 
use System.Drawing

class MyForm
	inherits Form

	def init
		.text = 'Click Me'
		listen .click, ref .handleClick

	def handleClick(sender as Object, args as EventArgs)
		MessageBox.show('You clicked me!', 'Click')

class Program

	def main is shared
		Application.run(MyForm())

}}}



== Notes ==

In most cases this syntax means you dont need to specify the commandline
-reference switch to provide the filename for a referenced namespace.


With  !MyProg.cobra containing

{{{
#!cobra
...
    use Foo.Bar
...
}}}
Instead of compilation by
{{{
cobra -reference:Foo.Bar MyProg.cobra
}}}

you can just say:


{{{
cobra MyProg.cobra
}}}