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+Design
+======
+
+Main assumption of the model is that the problem that we are to solve is the
+problem of the very long class names in PHP libraries. We would not attempt
+to take autoloader's job or create packaging model - only make names
+manageable.
+
+Namespaces are defined the following way:
+
+Zend/DB/Connection.php:
+<?php
+namespace Zend\DB;
+
+class Connection {
+}
+
+function connect() {
+}
+?>
+
+Namespace definition does the following:
+All class and function names inside are automatically prefixed with
+namespace name. Inside namespace, local name always takes precedence over
+global name. Several files may be using the same namespace.
+The namespace declaration statement must be the very first statement in
+the file. The only exception is "declare" statement that can be used before.
+
+Every class and function in a namespace can be referred to by the full name
+- e.g. Zend\DB\Connection or Zend\DB\connect - at any time.
+
+<?php
+require 'Zend/Db/Connection.php';
+$x = new Zend\DB\Connection;
+Zend\DB\connect();
+?>
+
+Namespace or class name can be imported:
+
+<?php
+require 'Zend/Db/Connection.php';
+use Zend\DB;
+use Zend\DB\Connection as DbConnection;
+
+$x = new Zend\DB\Connection();
+$y = new DB\connection();
+$z = new DbConnection();
+DB\connect();
+?>
+
+The use statement only defines name aliasing. It may create name alias for
+namespace or class. The simple form of statement "use A\B\C\D;" is
+equivalent to "use A\B\C\D as D;". The use statement can be used at any
+time in the global scope (not inside function/class) and takes effect from 
+the point of definition down to the end of file. It is recommended however to
+place the use statements at the beginning of the file. The use statements have
+effect only on the file where they appear.
+
+The special "empty" namespace (\ prefix) is useful as explicit global
+namespace qualification. All class and function names started from \
+interpreted as global.
+
+<?php 
+namespace A\B\C;
+
+$con = \mysql_connect(...);
+?>
+
+A special constant __NAMESPACE__ contains the name of the current namespace. 
+It can be used to construct fully-qualified names to pass them as callbacks.
+
+<?php
+namespace A\B\C;
+
+function foo() {
+}
+
+set_error_handler(__NAMESPACE__ . "\foo");
+?>
+
+In global namespace __NAMESPACE__ constant has the value of empty string.
+
+Names inside namespace are resolved according to the following rules:
+
+1) all qualified names are translated during compilation according to
+current import rules. So if we have "use A\B\C" and then "C\D\e()"
+it is translated to "A\B\C\D\e()".
+2) unqualified class names translated during compilation according to
+current import rules. So if we have "use A\B\C" and then "new C()" it
+is translated to "new A\B\C()".
+3) inside namespace, calls to unqualified functions that are defined in 
+current namespace (and are known at the time the call is parsed) are 
+interpreted as calls to these namespace functions.
+4) inside namespace, calls to unqualified functions that are not defined 
+in current namespace are resolved at run-time. The call to function foo() 
+inside namespace (A\B) first tries to find and call function from current 
+namespace A\B\foo() and if it doesn't exist PHP tries to call internal
+function foo(). Note that using foo() inside namespace you can call only 
+internal PHP functions, however using \foo() you are able to call any
+function from the global namespace.
+5) unqualified class names are resolved at run-time. E.q. "new Exception()"
+first tries to use (and autoload) class from current namespace and in case 
+of failure uses internal PHP class. Note that using "new A" in namespace 
+you can only create class from this namespace or internal PHP class, however
+using "new \A" you are able to create any class from the global namespace.
+6) Calls to qualified functions are resolved at run-time. Call to
+A\B\foo() first tries to call function foo() from namespace A\B, then
+it tries to find class A\B (__autoload() it if necessary) and call its
+static method foo()
+7) qualified class names are interpreted as class from corresponding
+namespace. So "new A\B\C()" refers to class C from namespace A\B.
+
+Examples
+--------
+<?php
+namespace A;
+foo();   // first tries to call "foo" defined in namespace "A"
+         // then calls internal function "foo"
+\foo(); // calls function "foo" defined in global scope
+?>
+
+<?php
+namespace A;
+new B();   // first tries to create object of class "B" defined in namespace "A"
+           // then creates object of internal class "B"
+new \B(); // creates object of class "B" defined in global scope
+?>
+
+<?php
+namespace A;
+new A(); // first tries to create object of class "A" from namespace "A" (A\A)
+         // then creates object of internal class "A"
+?>
+
+<?php
+namespace A;
+B\foo();   // first tries to call function "foo" from namespace "A\B"
+            // then calls method "foo" of internal class "B"
+\B\foo(); // first tries to call function "foo" from namespace "B"
+            // then calls method "foo" of class "B" from global scope
+?>
+
+The worst case if class name conflicts with namespace name
+<?php
+namespace A;
+A\foo();   // first tries to call function "foo" from namespace "A\A"
+            // then tries to call method "foo" of class "A" from namespace "A"
+            // then tries to call function "foo" from namespace "A"
+            // then calls method "foo" of internal class "A"
+\A\foo(); // first tries to call function "foo" from namespace "A"
+            // then calls method "foo" of class "A" from global scope
+?>
+
+TODO
+====
+
+* Support for namespace constants?
+
+* performance problems
+  - calls to internal functions in namespaces are slower, because PHP first
+    looks for such function in current namespace
+  - calls to static methods are slower, because PHP first tries to look
+    for corresponding function in namespace
+
+* Extend the Reflection API?
+  * Add ReflectionNamespace class
+    + getName()
+    + getClasses()
+    + getFunctions()
+    + getFiles()
+  * Add getNamespace() methods to ReflectionClass and ReflectionFunction
+
+* Rename namespaces to packages?
+