Added boost header

test/external/boost/lambda/closures.hpp

@@ -0,0 +1,274 @@
+/*=============================================================================
+    Adaptable closures
+
+    Phoenix V0.9
+    Copyright (c) 2001-2002 Joel de Guzman
+
+    Distributed under the Boost Software License, Version 1.0. (See
+    accompanying file LICENSE_1_0.txt or copy at
+    http://www.boost.org/LICENSE_1_0.txt)
+
+    URL: http://spirit.sourceforge.net/
+
+==============================================================================*/
+#ifndef PHOENIX_CLOSURES_HPP
+#define PHOENIX_CLOSURES_HPP
+
+///////////////////////////////////////////////////////////////////////////////
+#include "boost/lambda/core.hpp"
+///////////////////////////////////////////////////////////////////////////////
+namespace boost {
+namespace lambda {
+
+///////////////////////////////////////////////////////////////////////////////
+//
+//  Adaptable closures
+//
+//      The framework will not be complete without some form of closures
+//      support. Closures encapsulate a stack frame where local
+//      variables are created upon entering a function and destructed
+//      upon exiting. Closures provide an environment for local
+//      variables to reside. Closures can hold heterogeneous types.
+//
+//      Phoenix closures are true hardware stack based closures. At the
+//      very least, closures enable true reentrancy in lambda functions.
+//      A closure provides access to a function stack frame where local
+//      variables reside. Modeled after Pascal nested stack frames,
+//      closures can be nested just like nested functions where code in
+//      inner closures may access local variables from in-scope outer
+//      closures (accessing inner scopes from outer scopes is an error
+//      and will cause a run-time assertion failure).
+//
+//      There are three (3) interacting classes:
+//
+//      1) closure:
+//
+//      At the point of declaration, a closure does not yet create a
+//      stack frame nor instantiate any variables. A closure declaration
+//      declares the types and names[note] of the local variables. The
+//      closure class is meant to be subclassed. It is the
+//      responsibility of a closure subclass to supply the names for
+//      each of the local variable in the closure. Example:
+//
+//          struct my_closure : closure<int, string, double> {
+//
+//              member1 num;        // names the 1st (int) local variable
+//              member2 message;    // names the 2nd (string) local variable
+//              member3 real;       // names the 3rd (double) local variable
+//          };
+//
+//          my_closure clos;
+//
+//      Now that we have a closure 'clos', its local variables can be
+//      accessed lazily using the dot notation. Each qualified local
+//      variable can be used just like any primitive actor (see
+//      primitives.hpp). Examples:
+//
+//          clos.num = 30
+//          clos.message = arg1
+//          clos.real = clos.num * 1e6
+//
+//      The examples above are lazily evaluated. As usual, these
+//      expressions return composite actors that will be evaluated
+//      through a second function call invocation (see operators.hpp).
+//      Each of the members (clos.xxx) is an actor. As such, applying
+//      the operator() will reveal its identity:
+//
+//          clos.num() // will return the current value of clos.num
+//
+//      *** [note] Acknowledgement: Juan Carlos Arevalo-Baeza (JCAB)
+//      introduced and initilally implemented the closure member names
+//      that uses the dot notation.
+//
+//      2) closure_member
+//
+//      The named local variables of closure 'clos' above are actually
+//      closure members. The closure_member class is an actor and
+//      conforms to its conceptual interface. member1..memberN are
+//      predefined typedefs that correspond to each of the listed types
+//      in the closure template parameters.
+//
+//      3) closure_frame
+//
+//      When a closure member is finally evaluated, it should refer to
+//      an actual instance of the variable in the hardware stack.
+//      Without doing so, the process is not complete and the evaluated
+//      member will result to an assertion failure. Remember that the
+//      closure is just a declaration. The local variables that a
+//      closure refers to must still be instantiated.
+//
+//      The closure_frame class does the actual instantiation of the
+//      local variables and links these variables with the closure and
+//      all its members. There can be multiple instances of
+//      closure_frames typically situated in the stack inside a
+//      function. Each closure_frame instance initiates a stack frame
+//      with a new set of closure local variables. Example:
+//
+//          void foo()
+//          {
+//              closure_frame<my_closure> frame(clos);
+//              /* do something */
+//          }
+//
+//      where 'clos' is an instance of our closure 'my_closure' above.
+//      Take note that the usage above precludes locally declared
+//      classes. If my_closure is a locally declared type, we can still
+//      use its self_type as a paramater to closure_frame:
+//
+//          closure_frame<my_closure::self_type> frame(clos);
+//
+//      Upon instantiation, the closure_frame links the local variables
+//      to the closure. The previous link to another closure_frame
+//      instance created before is saved. Upon destruction, the
+//      closure_frame unlinks itself from the closure and relinks the
+//      preceding closure_frame prior to this instance.
+//
+//      The local variables in the closure 'clos' above is default
+//      constructed in the stack inside function 'foo'. Once 'foo' is
+//      exited, all of these local variables are destructed. In some
+//      cases, default construction is not desirable and we need to
+//      initialize the local closure variables with some values. This
+//      can be done by passing in the initializers in a compatible
+//      tuple. A compatible tuple is one with the same number of
+//      elements as the destination and where each element from the
+//      destination can be constructed from each corresponding element
+//      in the source. Example:
+//
+//          tuple<int, char const*, int> init(123, "Hello", 1000);
+//          closure_frame<my_closure> frame(clos, init);
+//
+//      Here now, our closure_frame's variables are initialized with
+//      int: 123, char const*: "Hello" and int: 1000.
+//
+///////////////////////////////////////////////////////////////////////////////
+
+
+
+///////////////////////////////////////////////////////////////////////////////
+//
+//  closure_frame class
+//
+///////////////////////////////////////////////////////////////////////////////
+template <typename ClosureT>
+class closure_frame : public ClosureT::tuple_t {
+
+public:
+
+    closure_frame(ClosureT& clos)
+    : ClosureT::tuple_t(), save(clos.frame), frame(clos.frame)
+    { clos.frame = this; }
+
+    template <typename TupleT>
+    closure_frame(ClosureT& clos, TupleT const& init)
+    : ClosureT::tuple_t(init), save(clos.frame), frame(clos.frame)
+    { clos.frame = this; }
+
+    ~closure_frame()
+    { frame = save; }
+
+private:
+
+    closure_frame(closure_frame const&);            // no copy
+    closure_frame& operator=(closure_frame const&); // no assign
+
+    closure_frame* save;
+    closure_frame*& frame;
+};
+
+///////////////////////////////////////////////////////////////////////////////
+//
+//  closure_member class
+//
+///////////////////////////////////////////////////////////////////////////////
+template <int N, typename ClosureT>
+class closure_member {
+
+public:
+
+    typedef typename ClosureT::tuple_t tuple_t;
+
+    closure_member()
+    : frame(ClosureT::closure_frame_ref()) {}
+
+    template <typename TupleT>
+    struct sig {
+
+        typedef typename detail::tuple_element_as_reference<
+            N, typename ClosureT::tuple_t
+        >::type type;
+    };
+
+    template <class Ret, class A, class B, class C>
+    //    typename detail::tuple_element_as_reference
+    //        <N, typename ClosureT::tuple_t>::type
+    Ret
+    call(A&, B&, C&) const
+    {
+        assert(frame);
+        return boost::tuples::get<N>(*frame);
+    }
+
+
+private:
+
+    typename ClosureT::closure_frame_t*& frame;
+};
+
+///////////////////////////////////////////////////////////////////////////////
+//
+//  closure class
+//
+///////////////////////////////////////////////////////////////////////////////
+template <
+    typename T0 = null_type,
+    typename T1 = null_type,
+    typename T2 = null_type,
+    typename T3 = null_type,
+    typename T4 = null_type
+>
+class closure {
+
+public:
+
+    typedef tuple<T0, T1, T2, T3, T4> tuple_t;
+    typedef closure<T0, T1, T2, T3, T4> self_t;
+    typedef closure_frame<self_t> closure_frame_t;
+
+                            closure()
+                            : frame(0)      { closure_frame_ref(&frame); }
+    closure_frame_t&        context()       { assert(frame); return frame; }
+    closure_frame_t const&  context() const { assert(frame); return frame; }
+
+    typedef lambda_functor<closure_member<0, self_t> > member1;
+    typedef lambda_functor<closure_member<1, self_t> > member2;
+    typedef lambda_functor<closure_member<2, self_t> > member3;
+    typedef lambda_functor<closure_member<3, self_t> > member4;
+    typedef lambda_functor<closure_member<4, self_t> > member5;
+
+private:
+
+    closure(closure const&);            // no copy
+    closure& operator=(closure const&); // no assign
+
+    template <int N, typename ClosureT>
+    friend class closure_member;
+
+    template <typename ClosureT>
+    friend class closure_frame;
+
+    static closure_frame_t*&
+    closure_frame_ref(closure_frame_t** frame_ = 0)
+    {
+        static closure_frame_t** frame = 0;
+        if (frame_ != 0)
+            frame = frame_;
+        return *frame;
+    }
+
+    closure_frame_t* frame;
+};
+
+}}
+   //  namespace 
+
+#endif