Implement namespaces chain.

doc/src/engine/custom-syntax.md

@@ -121,7 +121,7 @@ where:
 * `context: &mut EvalContext` - mutable reference to the current evaluation _context_, exposing the following:
   * `context.scope: &mut Scope` - mutable reference to the current [`Scope`]; variables can be added to/removed from it.
   * `context.engine(): &Engine` - reference to the current [`Engine`].
-  * `context.namespace(): &Module` - reference to the current _global namespace_ (as a [module]) containing all script-defined functions.
+  * `context.namespaces(): &[&Module]` - reference to the chain of namespaces (as a slice of [modules]) containing all script-defined functions.
   * `context.this_ptr(): Option<&Dynamic>` - reference to the current bound [`this`] pointer, if any.
   * `context.call_level(): usize` - the current nesting level of function calls.
 

doc/src/engine/var.md

@@ -77,7 +77,7 @@ where:
 * `context: &EvalContext` - reference to the current evaluation _context_, which exposes the following fields:
   * `context.scope: &Scope` - reference to the current [`Scope`] containing all variables up to the current evaluation position.
   * `context.engine(): &Engine` - reference to the current [`Engine`].
-  * `context.namespace(): &Module` - reference to the current _global namespace_ (as a [module]) containing all script-defined functions.
+  * `context.namespaces(): &[&Module]` - reference to the chain of namespaces (as a slice of [modules]) containing all script-defined functions.
   * `context.this_ptr(): Option<&Dynamic>` - reference to the current bound [`this`] pointer, if any.
   * `context.call_level(): usize` - the current nesting level of function calls.
 

doc/src/language/fn-ptr.md

@@ -249,8 +249,8 @@ let fn_ptr = engine.eval_ast::<FnPtr>(&ast)?;
 ast.retain_functions(|_, _, _| true);
 
 // Create native call context via a tuple containing the Engine and the
-// set of script-defined functions (within the AST)
-let context = (&engine, ast.as_ref()).into();
+// set of script-defined functions (within the AST) in form of a slice.
+let context = (&engine, &[ast.as_ref()]).into();
 
 // 'f' captures: the engine, the AST, and the closure
 let f = move |x: i64| fn_ptr.call_dynamic(context, None, [x.into()]);

doc/src/rust/register-raw.md

@@ -72,8 +72,7 @@ where:
   * `context.engine(): &Engine` - the current [`Engine`], with all configurations and settings.
     This is sometimes useful for calling a script-defined function within the same evaluation context
     using [`Engine::call_fn`][`call_fn`], or calling a [function pointer].
-
-  * `context.namespace(): &Module` - the global namespace of script-defined functions, as a [`Module`].
+  * `context.namespaces(): &[&Module]` - reference to the chain of namespaces (as a slice of [modules]) containing all script-defined functions.
 
 * `args: &mut [&mut Dynamic]` - a slice containing `&mut` references to [`Dynamic`] values.
   The slice is guaranteed to contain enough arguments _of the correct types_.