////////////////////////////////////////////////////////////////////////////
// lazy_list.hpp
//
// Build lazy operations for Phoenix equivalents for FC++
//
// These are equivalents of the Boost FC++ functoids in list.hpp
//
// Implemented so far:
//
// head tail null
//
// strict_list<T> and associated iterator.
//
// list<T> and odd_list<T>
//
// cons cat
//
// Comparisons between list and odd_list types and separately for strict_list.
//
// NOTES: There is a fix at the moment as I have not yet sorted out
// how to get back the return type of a functor returning a list type.
// For the moment I have fixed this as odd_list<T> at two locations,
// one in list<T> and one in Cons. I am going to leave it like this
// for now as reading the code, odd_list<T> seems to be correct.
//
// I am also not happy at the details needed to detect types in Cons.
//
// I think the structure of this file is now complete.
// John Fletcher February 2015.
//
////////////////////////////////////////////////////////////////////////////
/*=============================================================================
Copyright (c) 2000-2003 Brian McNamara and Yannis Smaragdakis
Copyright (c) 2001-2007 Joel de Guzman
Copyright (c) 2015 John Fletcher
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)
==============================================================================*/
///////////////////////////////////////////////////////////////////////
// This is from Boost FC++ list.hpp reimplemented without Fun0 or Full0
///////////////////////////////////////////////////////////////////////
/*
concept ListLike: Given a list representation type L
L<T> inherits ListLike and has
// typedefs just show typical values
typedef T value_type
typedef L<T> force_result_type
typedef L<T> delay_result_type
typedef L<T> tail_result_type
template <class UU> struct cons_rebind {
typedef L<UU> type; // force type
typedef L<UU> delay_type; // delay type
};
L()
L( a_unique_type_for_nil )
template <class F> L(F) // F :: ()->L
constructor: force_result_type( T, L<T> )
template <class F>
constructor: force_result_type( T, F ) // F :: ()->L
template <class It>
L( It, It )
// FIX THIS instead of operator bool(), does Boost have something better?
operator bool() const
force_result_type force() const
delay_result_type delay() const
T head() const
tail_result_type tail() const
static const bool is_lazy; // true if can represent infinite lists
typedef const_iterator;
typedef const_iterator iterator; // ListLikes are immutable
iterator begin() const
iterator end() const
*/
//////////////////////////////////////////////////////////////////////
// End of section from Boost FC++ list.hpp
//////////////////////////////////////////////////////////////////////
#ifndef BOOST_PHOENIX_FUNCTION_LAZY_LIST
#define BOOST_PHOENIX_FUNCTION_LAZY_LIST
#include <boost/phoenix/core.hpp>
#include <boost/phoenix/function.hpp>
#include <boost/intrusive_ptr.hpp>
#include <boost/function.hpp>
#include <boost/type_traits/type_with_alignment.hpp>
//#include "lazy_reuse.hpp"
namespace boost {
namespace phoenix {
//////////////////////////////////////////////////////////////////////
// These are the list types being declared.
//////////////////////////////////////////////////////////////////////
template <class T> class strict_list;
namespace impl {
template <class T> class list;
template <class T> class odd_list;
}
// in ref_count.hpp in BoostFC++ now in lazy_operator.hpp
//typedef unsigned int RefCountType;
//////////////////////////////////////////////////////////////////////
// a_unique_type_for_nil moved to lazy_operator.hpp.
//////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////
// Distinguish lazy lists (list and odd_list) from strict_list.
//////////////////////////////////////////////////////////////////////
namespace lazy {
// Copied from Boost FC++ list.hpp
template <class L, bool is_lazy> struct ensure_lazy_helper {};
template <class L> struct ensure_lazy_helper<L,true> {
static void requires_lazy_list_to_prevent_infinite_recursion() {}
};
template <class L>
void ensure_lazy() {
ensure_lazy_helper<L,L::is_lazy>::
requires_lazy_list_to_prevent_infinite_recursion();
}
}
//////////////////////////////////////////////////////////////////////
// Provide remove reference for types defined for list types.
//////////////////////////////////////////////////////////////////////
namespace result_of {
template < typename L >
class ListType
{
public:
typedef typename boost::remove_reference<L>::type LType;
typedef typename LType::value_type value_type;
typedef typename LType::tail_result_type tail_result_type;
typedef typename LType::force_result_type force_result_type;
typedef typename LType::delay_result_type delay_result_type;
};
template <>
class ListType<a_unique_type_for_nil>
{
public:
typedef a_unique_type_for_nil LType;
//typedef a_unique_type_for_nil value_type;
};
template <typename F, typename T>
struct ResultType {
typedef typename impl::odd_list<T> type;
};
}
//////////////////////////////////////////////////////////////////////
// ListLike is a property inherited by any list type to enable it to
// work with the functions being implemented in this file.
// It provides the check for the structure described above.
//////////////////////////////////////////////////////////////////////
namespace listlike {
struct ListLike {}; // This lets us use is_base_and_derived() to see
// (at compile-time) what classes are user-defined lists.
template <class L, bool is_lazy> struct ensure_lazy_helper {};
template <class L> struct ensure_lazy_helper<L,true> {
static void requires_lazy_list_to_prevent_infinite_recursion() {}
};
template <class L>
void ensure_lazy() {
ensure_lazy_helper<L,L::is_lazy>::
requires_lazy_list_to_prevent_infinite_recursion();
}
template <class L, bool b>
struct EnsureListLikeHelp {
static void trying_to_call_a_list_function_on_a_non_list() {}
};
template <class L> struct EnsureListLikeHelp<L,false> { };
template <class L>
void EnsureListLike() {
typedef typename result_of::ListType<L>::LType LType;
EnsureListLikeHelp<L,boost::is_base_and_derived<ListLike,LType>::value>::
trying_to_call_a_list_function_on_a_non_list();
}
template <class L>
bool is_a_unique_type_for_nil(const L& /*l*/) {
return false;
}
template <>
bool is_a_unique_type_for_nil<a_unique_type_for_nil>
(const a_unique_type_for_nil& /* n */) {
return true;
}
template <class L>
struct detect_nil {
static const bool is_nil = false;
};
template <>
struct detect_nil<a_unique_type_for_nil> {
static const bool is_nil = true;
};
template <>
struct detect_nil<a_unique_type_for_nil&> {
static const bool is_nil = true;
};
template <>
struct detect_nil<const a_unique_type_for_nil&> {
static const bool is_nil = true;
};
}
//////////////////////////////////////////////////////////////////////
// Implement lazy functions for list types. cat and cons come later.
//////////////////////////////////////////////////////////////////////
#ifndef BOOST_PHOENIX_FUNCTION_MAX_LAZY_LIST_LENGTH
#define BOOST_PHOENIX_FUNCTION_MAX_LAZY_LIST_LENGTH 1000
#endif
namespace impl {
struct Head
{
template <typename Sig>
struct result;
template <typename This, typename L>
struct result<This(L)>
{
typedef typename result_of::ListType<L>::value_type type;
};
template <typename L>
typename result<Head(L)>::type
operator()(const L & l) const
{
listlike::EnsureListLike<L>();
return l.head();
}
};
struct Tail
{
template <typename Sig>
struct result;
template <typename This, typename L>
struct result<This(L)>
{
typedef typename result_of::ListType<L>::tail_result_type type;
};
template <typename L>
typename result<Tail(L)>::type
operator()(const L & l) const
{
listlike::EnsureListLike<L>();
return l.tail();
}
};
struct Null
{
template <typename Sig>
struct result;
template <typename This, typename L>
struct result<This(L)>
{
typedef bool type;
};
template <typename L>
typename result<Null(L)>::type
//bool
operator()(const L& l) const
{
listlike::EnsureListLike<L>();
return !l;
}
};
struct Delay {
template <typename Sig>
struct result;
template <typename This, typename L>
struct result<This(L)>
{
typedef typename result_of::ListType<L>::delay_result_type type;
};
template <typename L>
typename result<Delay(L)>::type
operator()(const L & l) const
{
listlike::EnsureListLike<L>();
return l.delay();
}
};
struct Force {
template <typename Sig>
struct result;
template <typename This, typename L>
struct result<This(L)>
{
typedef typename result_of::ListType<L>::force_result_type type;
};
template <typename L>
typename result<Force(L)>::type
operator()(const L & l) const
{
listlike::EnsureListLike<L>();
return l.force();
}
};
}
//BOOST_PHOENIX_ADAPT_CALLABLE(head, impl::head, 1)
//BOOST_PHOENIX_ADAPT_CALLABLE(tail, impl::tail, 1)
//BOOST_PHOENIX_ADAPT_CALLABLE(null, impl::null, 1)
typedef boost::phoenix::function<impl::Head> Head;
typedef boost::phoenix::function<impl::Tail> Tail;
typedef boost::phoenix::function<impl::Null> Null;
typedef boost::phoenix::function<impl::Delay> Delay;
typedef boost::phoenix::function<impl::Force> Force;
Head head;
Tail tail;
Null null;
Delay delay;
Force force;
//////////////////////////////////////////////////////////////////////
// These definitions used for strict_list are imported from BoostFC++
// unchanged.
//////////////////////////////////////////////////////////////////////
namespace impl {
template <class T>
struct strict_cons : public boost::noncopyable {
mutable RefCountType refC;
T head;
typedef boost::intrusive_ptr<strict_cons> tail_type;
tail_type tail;
strict_cons( const T& h, const tail_type& t ) : refC(0), head(h), tail(t) {}
};
template <class T>
void intrusive_ptr_add_ref( const strict_cons<T>* p ) {
++ (p->refC);
}
template <class T>
void intrusive_ptr_release( const strict_cons<T>* p ) {
if( !--(p->refC) ) delete p;
}
template <class T>
class strict_list_iterator {
typedef boost::intrusive_ptr<strict_cons<T> > rep_type;
rep_type l;
bool is_nil;
void advance() {
l = l->tail;
if( !l )
is_nil = true;
}
class Proxy { // needed for operator->
const T x;
friend class strict_list_iterator;
Proxy( const T& xx ) : x(xx) {}
public:
const T* operator->() const { return &x; }
};
public:
typedef std::input_iterator_tag iterator_category;
typedef T value_type;
typedef ptrdiff_t difference_type;
typedef T* pointer;
typedef T& reference;
strict_list_iterator() : l(), is_nil(true) {}
explicit strict_list_iterator( const rep_type& ll ) : l(ll), is_nil(!ll) {}
const T operator*() const { return l->head; }
const Proxy operator->() const { return Proxy(l->head); }
strict_list_iterator<T>& operator++() {
advance();
return *this;
}
const strict_list_iterator<T> operator++(int) {
strict_list_iterator<T> i( *this );
advance();
return i;
}
bool operator==( const strict_list_iterator<T>& i ) const {
return is_nil && i.is_nil;
}
bool operator!=( const strict_list_iterator<T>& i ) const {
return ! this->operator==(i);
}
};
}
//////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////
template <class T>
class strict_list : public listlike::ListLike
{
typedef boost::intrusive_ptr<impl::strict_cons<T> > rep_type;
rep_type rep;
struct Make {};
template <class Iter>
static rep_type help( Iter a, const Iter& b ) {
rep_type r;
while( a != b ) {
T x( *a );
r = rep_type( new impl::strict_cons<T>( x, r ) );
++a;
}
return r;
}
public:
static const bool is_lazy = false;
typedef T value_type;
typedef strict_list force_result_type;
typedef strict_list delay_result_type;
typedef strict_list tail_result_type;
template <class UU> struct cons_rebind {
typedef strict_list<UU> type;
typedef strict_list<UU> delay_type;
};
strict_list( Make, const rep_type& r ) : rep(r) {}
strict_list() : rep() {}
strict_list( a_unique_type_for_nil ) : rep() {}
template <class F>
strict_list( const F& f ) : rep( f().rep ) {
// I cannot do this yet.
//functoid_traits<F>::template ensure_accepts<0>::args();
}
strict_list( const T& x, const strict_list& y )
: rep( new impl::strict_cons<T>(x,y.rep) ) {}
template <class F>
strict_list( const T& x, const F& f )
: rep( new impl::strict_cons<T>(x,f().rep) ) {}
operator bool() const { return (bool)rep; }
force_result_type force() const { return *this; }
delay_result_type delay() const { return *this; }
T head() const {
#ifndef BOOST_PHOENIX_NO_LAZY_EXCEPTIONS
if( !*this )
throw lazy_exception("Tried to take head() of empty strict_list");
#endif
return rep->head;
}
tail_result_type tail() const {
#ifndef BOOST_PHOENIX_NO_LAZY_EXCEPTIONS
if( !*this )
throw lazy_exception("Tried to take tail() of empty strict_list");
#endif
return strict_list(Make(),rep->tail);
}
template <class Iter>
strict_list( const Iter& a, const Iter& b ) : rep( rep_type() ) {
// How ironic. We need to reverse the iterator range in order to
// non-recursively build this!
std::vector<T> tmp(a,b);
rep = help( tmp.rbegin(), tmp.rend() );
}
// Since the strict_cons destructor can't call the strict_list
// destructor, the "simple" iterative destructor is correct and
// efficient. Hurray.
~strict_list() { while(rep && (rep->refC == 1)) rep = rep->tail; }
// The following helps makes strict_list almost an STL "container"
typedef impl::strict_list_iterator<T> const_iterator;
typedef const_iterator iterator; // strict_list is immutable
iterator begin() const { return impl::strict_list_iterator<T>( rep ); }
iterator end() const { return impl::strict_list_iterator<T>(); }
};
// All of these null head and tail are now non lazy using e.g. null(a)().
// They need an extra () e.g. null(a)().
template <class T>
bool operator==( const strict_list<T>& a, a_unique_type_for_nil ) {
return null(a)();
}
template <class T>
bool operator==( a_unique_type_for_nil, const strict_list<T>& a ) {
return null(a)();
}
template <class T>
bool operator==( const strict_list<T>& a, const strict_list<T>& b ) {
if( null(a)() && null(b)() )
return true;
if( null(a)() || null(b)() )
return false;
return (head(a)()==head(b)()) &&
(tail(a)()==tail(b)());
}
template <class T>
bool operator<( const strict_list<T>& a, const strict_list<T>& b ) {
if( null(a)() && !null(b)() ) return true;
if( null(b)() ) return false;
if( head(b)() < head(a)() ) return false;
if( head(a)() < head(b)() ) return true;
return (tail(a)() < tail(b)());
}
template <class T>
bool operator<( const strict_list<T>&, a_unique_type_for_nil ) {
return false;
}
template <class T>
bool operator<( a_unique_type_for_nil, const strict_list<T>& b ) {
return !(null(b)());
}
//////////////////////////////////////////////////////////////////////
// Class list<T> is the primary interface to the user for lazy lists.
//////////////////////////////////////////////////////////////////////{
namespace impl {
using fcpp::INV;
using fcpp::VAR;
using fcpp::reuser2;
struct CacheEmpty {};
template <class T> class Cache;
template <class T> class odd_list;
template <class T> class list_iterator;
template <class It, class T>
struct ListItHelp2 /*: public c_fun_type<It,It,odd_list<T> >*/ {
// This will need a return type.
typedef odd_list<T> return_type;
odd_list<T> operator()( It begin, const It& end,
reuser2<INV,VAR,INV,ListItHelp2<It,T>,It,It> r = NIL ) const;
};
template <class U,class F> struct cvt;
template <class T, class F, class R> struct ListHelp;
template <class T> Cache<T>* xempty_helper();
template <class T, class F, class L, bool b> struct ConsHelp2;
struct ListRaw {};
template <class T>
class list : public listlike::ListLike
{
// never NIL, unless an empty odd_list
boost::intrusive_ptr<Cache<T> > rep;
template <class U> friend class Cache;
template <class U> friend class odd_list;
template <class TT, class F, class L, bool b> friend struct ConsHelp2;
template <class U,class F> friend struct cvt;
list( const boost::intrusive_ptr<Cache<T> >& p ) : rep(p) { }
list( ListRaw, Cache<T>* p ) : rep(p) { }
bool priv_isEmpty() const {
return rep->cache().second.rep == Cache<T>::XNIL();
}
T priv_head() const {
#ifndef BOOST_PHOENIX_NO_LAZY_EXCEPTIONS
if( priv_isEmpty() )
throw lazy_exception("Tried to take head() of empty list");
#endif
return rep->cache().first();
}
list<T> priv_tail() const {
#ifndef BOOST_PHOENIX_NO_LAZY_EXCEPTIONS
if( priv_isEmpty() )
throw lazy_exception("Tried to take tail() of empty list");
#endif
return rep->cache().second;
}
public:
static const bool is_lazy = true;
typedef T value_type;
typedef list tail_result_type;
typedef odd_list<T> force_result_type;
typedef list delay_result_type;
template <class UU> struct cons_rebind {
typedef odd_list<UU> type;
typedef list<UU> delay_type;
};
list( a_unique_type_for_nil ) : rep( Cache<T>::XEMPTY() ) { }
list() : rep( Cache<T>::XEMPTY() ) { }
template <class F> // works on both ()->odd_list and ()->list
// At the moment this is fixed for odd_list<T>.
// I need to do more work to get the general result.
list( const F& f )
: rep( ListHelp<T,F,odd_list<T> >()(f) ) { }
//: rep( ListHelp<T,F,typename F::result_type>()(f) ) { }
operator bool() const { return !priv_isEmpty(); }
const force_result_type& force() const { return rep->cache(); }
const delay_result_type& delay() const { return *this; }
// Note: force returns a reference;
// implicit conversion now returns a copy.
operator odd_list<T>() const { return force(); }
T head() const { return priv_head(); }
tail_result_type tail() const { return priv_tail(); }
// The following helps makes list almost an STL "container"
typedef list_iterator<T> const_iterator;
typedef const_iterator iterator; // list is immutable
iterator begin() const { return list_iterator<T>( *this ); }
iterator end() const { return list_iterator<T>(); }
// end of list<T>
};
//////////////////////////////////////////////////////////////////////
// Class odd_list<T> is not normally accessed by the user.
//////////////////////////////////////////////////////////////////////
struct OddListDummyY {};
template <class T>
class odd_list : public listlike::ListLike
{
public:
typedef
typename boost::type_with_alignment<boost::alignment_of<T>::value>::type
xfst_type;
private:
union { xfst_type fst; unsigned char dummy[sizeof(T)]; };
const T& first() const {
return *static_cast<const T*>(static_cast<const void*>(&fst));
}
T& first() {
return *static_cast<T*>(static_cast<void*>(&fst));
}
list<T> second; // If XNIL, then this odd_list is NIL
template <class U> friend class list;
template <class U> friend class Cache;
odd_list( OddListDummyY )
: second( Cache<T>::XBAD() ) { }
void init( const T& x ) {
new (static_cast<void*>(&fst)) T(x);
}
bool fst_is_valid() const {
if( second.rep != Cache<T>::XNIL() )
if( second.rep != Cache<T>::XBAD() )
return true;
return false;
}
bool priv_isEmpty() const { return second.rep == Cache<T>::XNIL(); }
T priv_head() const {
#ifndef BOOST_PHOENIX_NO_LAZY_EXCEPTIONS
if( priv_isEmpty() )
throw lazy_exception("Tried to take head() of empty odd_list");
#endif
return first();
}
list<T> priv_tail() const {
#ifndef BOOST_PHOENIX_NO_LAZY_EXCEPTIONS
if( priv_isEmpty() )
throw lazy_exception("Tried to take tail() of empty odd_list");
#endif
return second;
}
public:
static const bool is_lazy = true;
typedef T value_type;
typedef list<T> tail_result_type;
typedef odd_list<T> force_result_type;
typedef list<T> delay_result_type;
template <class UU> struct cons_rebind {
typedef odd_list<UU> type;
typedef list<UU> delay_type;
};
odd_list() : second( Cache<T>::XNIL() ) { }
odd_list( a_unique_type_for_nil ) : second( Cache<T>::XNIL() ) { }
odd_list( const T& x, const list<T>& y ) : second(y) { init(x); }
odd_list( const T& x, a_unique_type_for_nil ) : second(NIL) { init(x); }
odd_list( const odd_list<T>& x ) : second(x.second) {
if( fst_is_valid() ) {
init( x.first() );
}
}
template <class It>
odd_list( It begin, const It& end )
: second( begin==end ? Cache<T>::XNIL() :
( init(*begin++), list<T>( begin, end ) ) ) {}
odd_list<T>& operator=( const odd_list<T>& x ) {
if( this == &x ) return *this;
if( fst_is_valid() ) {
if( x.fst_is_valid() )
first() = x.first();
else
first().~T();
}
else {
if( x.fst_is_valid() )
init( x.first() );
}
second = x.second;
return *this;
}
~odd_list() {
if( fst_is_valid() ) {
first().~T();
}
}
operator bool() const { return !priv_isEmpty(); }
const force_result_type& force() const { return *this; }
delay_result_type delay() const { return list<T>(*this); }
T head() const { return priv_head(); }
tail_result_type tail() const { return priv_tail(); }
// The following helps makes odd_list almost an STL "container"
typedef list_iterator<T> const_iterator;
typedef const_iterator iterator; // odd_list is immutable
iterator begin() const { return list_iterator<T>( this->delay() ); }
iterator end() const { return list_iterator<T>(); }
// end of odd_list<T>
};
//////////////////////////////////////////////////////////////////////
// struct cvt
//////////////////////////////////////////////////////////////////////
// This converts ()->list<T> to ()->odd_list<T>.
// In other words, here is the 'extra work' done when using the
// unoptimized interface.
template <class U,class F>
struct cvt /*: public c_fun_type<odd_list<U> >*/ {
typedef odd_list<U> return_type;
F f;
cvt( const F& ff ) : f(ff) {}
odd_list<U> operator()() const {
list<U> l = f();
return l.force();
}
};
//////////////////////////////////////////////////////////////////////
// Cache<T> and associated functions.
//////////////////////////////////////////////////////////////////////
// I malloc a RefCountType to hold the refCount and init it to 1 to ensure the
// refCount will never get to 0, so the destructor-of-global-object
// order at the end of the program is a non-issue. In other words, the
// memory allocated here is only reclaimed by the operating system.
template <class T>
Cache<T>* xnil_helper() {
void *p = std::malloc( sizeof(RefCountType) );
*((RefCountType*)p) = 1;
return static_cast<Cache<T>*>( p );
}
template <class T>
Cache<T>* xnil_helper_nil() {
Cache<T>* p = xnil_helper<T>();
return p;
}
template <class T>
Cache<T>* xnil_helper_bad() {
Cache<T>* p = xnil_helper<T>();
return p;
}
template <class T>
Cache<T>* xempty_helper() {
Cache<T>* p = new Cache<T>( CacheEmpty() );
return p;
}
// This makes a boost phoenix function type with return type
// odd_list<T>
template <class T>
struct fun0_type_helper{
typedef boost::function0<odd_list<T> > fun_type;
typedef boost::phoenix::function<fun_type> phx_type;
};
template <class T>
struct make_fun0_odd_list {
typedef typename fun0_type_helper<T>::fun_type fun_type;
typedef typename fun0_type_helper<T>::phx_type phx_type;
typedef phx_type result_type;
template <class F>
result_type operator()(const F& f) const
{
fun_type ff(f);
phx_type g(ff);
return g;
}
// Overload for the case where it is a boost phoenix function already.
template <class F>
typename boost::phoenix::function<F> operator()
(const boost::phoenix::function<F>& f) const
{
return f;
}
};
template <class T>
class Cache : boost::noncopyable {
mutable RefCountType refC;
// This is the boost::function type
typedef typename fun0_type_helper<T>::fun_type fun_odd_list_T;
// This is the boost::phoenix::function type;
typedef typename fun0_type_helper<T>::phx_type fun0_odd_list_T;
mutable fun0_odd_list_T fxn;
mutable odd_list<T> val;
// val.second.rep can be XBAD, XNIL, or a valid ptr
// - XBAD: val is invalid (fxn is valid)
// - XNIL: this is the empty list
// - anything else: val.first() is head, val.second is tail()
// This functoid should never be called; it represents a
// self-referent Cache, which should be impossible under the current
// implementation. Nonetheless, we need a 'dummy' function object to
// represent invalid 'fxn's (val.second.rep!=XBAD), and this
// implementation seems to be among the most reasonable.
struct blackhole_helper /*: c_fun_type< odd_list<T> >*/ {
typedef odd_list<T> return_type;
odd_list<T> operator()() const {
#ifndef BOOST_PHOENIX_NO_LAZY_EXCEPTIONS
throw lazy_exception("You have entered a black hole.");
#else
return odd_list<T>();
#endif
}
};
// Don't get rid of these XFOO() functions; they impose no overhead,
// and provide a useful place to add debugging code for tracking down
// before-main()-order-of-initialization problems.
static const boost::intrusive_ptr<Cache<T> >& XEMPTY() {
static boost::intrusive_ptr<Cache<T> > xempty( xempty_helper<T>() );
return xempty;
}
static const boost::intrusive_ptr<Cache<T> >& XNIL() {
// this list is nil
static boost::intrusive_ptr<Cache<T> > xnil( xnil_helper_nil<T>() );
return xnil;
}
static const boost::intrusive_ptr<Cache<T> >& XBAD() {
// the pair is invalid; use fxn
static boost::intrusive_ptr<Cache<T> > xbad( xnil_helper_bad<T>() );
return xbad;
}
static fun0_odd_list_T /*<odd_list<T> >*/ the_blackhole;
static fun0_odd_list_T& blackhole() {
static fun0_odd_list_T the_blackhole;
//( make_fun0_odd_list<T>()( blackhole_helper() ) );
return the_blackhole;
}
odd_list<T>& cache() const {
if( val.second.rep == XBAD() ) {
val = fxn()();
fxn = blackhole();
}
return val;
}
template <class U> friend class list;
template <class U> friend class odd_list;
template <class TT, class F, class L, bool b> friend struct ConsHelp2;
template <class U,class F> friend struct cvt;
template <class U, class F, class R> friend struct ListHelp;
template <class U> friend Cache<U>* xempty_helper();
Cache( CacheEmpty ) : refC(0), fxn(blackhole()), val() {}
Cache( const odd_list<T>& x ) : refC(0), fxn(blackhole()), val(x) {}
Cache( const T& x, const list<T>& l ) : refC(0),fxn(blackhole()),val(x,l)
{}
Cache( const fun0_odd_list_T& f )
: refC(0), fxn(f), val( OddListDummyY() ) {}
// f must be a boost phoenix function object?
template <class F>
Cache( const F& f ) // ()->odd_list
: refC(0), fxn(make_fun0_odd_list<T>()(f)), val( OddListDummyY() ) {}
// This is for ()->list<T> to ()->odd_list<T>
struct CvtFxn {};
template <class F>
Cache( CvtFxn, const F& f ) // ()->list
: refC(0), fxn(make_fun0_odd_list<T>()(cvt<T,F>(f))), val( OddListDummyY() ) {}
template <class X>
friend void intrusive_ptr_add_ref( const Cache<X>* p );
template <class X>
friend void intrusive_ptr_release( const Cache<X>* p );
};
template <class T>
void intrusive_ptr_add_ref( const Cache<T>* p ) {
++ (p->refC);
}
template <class T>
void intrusive_ptr_release( const Cache<T>* p ) {
if( !--(p->refC) ) delete p;
}
//////////////////////////////////////////////////////////////////////
// Rest of list's stuff
//////////////////////////////////////////////////////////////////////
template <class T, class F> struct ListHelp<T,F,list<T> > {
boost::intrusive_ptr<Cache<T> > operator()( const F& f ) const {
return boost::intrusive_ptr<Cache<T> >
(new Cache<T>(typename Cache<T>::CvtFxn(),f));
}
};
template <class T, class F> struct ListHelp<T,F,odd_list<T> > {
boost::intrusive_ptr<Cache<T> > operator()( const F& f ) const {
return boost::intrusive_ptr<Cache<T> >(new Cache<T>(f));
}
};
template <class T>
class list_iterator {
list<T> l;
bool is_nil;
void advance() {
l = l.tail();
if( !l )
is_nil = true;
}
class Proxy { // needed for operator->
const T x;
friend class list_iterator;
Proxy( const T& xx ) : x(xx) {}
public:
const T* operator->() const { return &x; }
};
public:
typedef std::input_iterator_tag iterator_category;
typedef T value_type;
typedef ptrdiff_t difference_type;
typedef T* pointer;
typedef T& reference;
list_iterator() : l(), is_nil(true) {}
explicit list_iterator( const list<T>& ll ) : l(ll), is_nil(!ll) {}
const T operator*() const { return l.head(); }
const Proxy operator->() const { return Proxy(l.head()); }
list_iterator<T>& operator++() {
advance();
return *this;
}
const list_iterator<T> operator++(int) {
list_iterator<T> i( *this );
advance();
return i;
}
bool operator==( const list_iterator<T>& i ) const {
return is_nil && i.is_nil;
}
bool operator!=( const list_iterator<T>& i ) const {
return ! this->operator==(i);
}
};
} // namespace impl
using impl::list;
using impl::odd_list;
using impl::list_iterator;
//////////////////////////////////////////////////////////////////////
// op== and op<, overloaded for all combos of list, odd_list, and NIL
//////////////////////////////////////////////////////////////////////
// All of these null head and tail are now non lazy using e.g. null(a)().
// They need an extra () e.g. null(a)().
// FIX THIS comparison operators can be implemented simpler with enable_if
template <class T>
bool operator==( const odd_list<T>& a, a_unique_type_for_nil ) {
return null(a)();
}
template <class T>
bool operator==( const list<T>& a, a_unique_type_for_nil ) {
return null(a)();
}
template <class T>
bool operator==( a_unique_type_for_nil, const odd_list<T>& a ) {
return null(a)();
}
template <class T>
bool operator==( a_unique_type_for_nil, const list<T>& a ) {
return null(a)();
}
template <class T>
bool operator==( const list<T>& a, const list<T>& b ) {
if( null(a)() && null(b)() )
return true;
if( null(a)() || null(b)() )
return false;
return (head(a)()==head(b)()) && (tail(a)()==tail(b)());
}
template <class T>
bool operator==( const odd_list<T>& a, const odd_list<T>& b ) {
if( null(a)() && null(b)() )
return true;
if( null(a)() || null(b)() )
return false;
return (head(a)()==head(b)()) && (tail(a)()==tail(b)());
}
template <class T>
bool operator==( const list<T>& a, const odd_list<T>& b ) {
if( null(a)() && null(b)() )
return true;
if( null(a)() || null(b)() )
return false;
return (head(a)()==head(b)()) && (tail(a)()==tail(b)());
}
template <class T>
bool operator==( const odd_list<T>& a, const list<T>& b ) {
if( null(a)() && null(b)() )
return true;
if( null(a)() || null(b)() )
return false;
return (head(a)()==head(b)()) && (tail(a)()==tail(b)());
}
template <class T>
bool operator<( const list<T>& a, const list<T>& b ) {
if( null(a)() && !null(b)() ) return true;
if( null(b)() ) return false;
if( head(b)() < head(a)() ) return false;
if( head(a)() < head(b)() ) return true;
return (tail(a)() < tail(b)());
}
template <class T>
bool operator<( const odd_list<T>& a, const list<T>& b ) {
if( null(a)() && !null(b)() ) return true;
if( null(b)() ) return false;
if( head(b)() < head(a)() ) return false;
if( head(a)() < head(b)() ) return true;
return (tail(a)() < tail(b)());
}
template <class T>
bool operator<( const list<T>& a, const odd_list<T>& b ) {
if( null(a) && !null(b) ) return true;
if( null(b) ) return false;
if( head(b) < head(a) ) return false;
if( head(a) < head(b) ) return true;
return (tail(a) < tail(b));
}
template <class T>
bool operator<( const odd_list<T>& a, const odd_list<T>& b ) {
if( null(a)() && !null(b)() ) return true;
if( null(b)() ) return false;
if( head(b)() < head(a)() ) return false;
if( head(a)() < head(b)() ) return true;
return (tail(a)() < tail(b)());
}
template <class T>
bool operator<( const odd_list<T>&, a_unique_type_for_nil ) {
return false;
}
template <class T>
bool operator<( const list<T>&, a_unique_type_for_nil ) {
return false;
}
template <class T>
bool operator<( a_unique_type_for_nil, const odd_list<T>& b ) {
return !null(b)();
}
template <class T>
bool operator<( a_unique_type_for_nil, const list<T>& b ) {
return !null(b)();
}
//////////////////////////////////////////////////////////////////////
// Implement cat and cons after the list types are defined.
//////////////////////////////////////////////////////////////////////
namespace impl {
using listlike::ListLike;
template <class T, class F, class L>
struct ConsHelp2<T,F,L,true>
{
typedef typename boost::remove_reference<T>::type TT;
typedef typename L::force_result_type type;
static type go( const TT& x, const F& f ) {
return type( x, f );
}
};
template <class T, class F>
struct ConsHelp2<T,F,list<T>,true>
{
typedef typename boost::remove_reference<T>::type TT;
typedef list<TT> L;
typedef typename L::force_result_type type;
static type go( const TT& x, const F& f ) {
return odd_list<TT>(x, list<TT>(
boost::intrusive_ptr<Cache<TT> >(new Cache<T>(
typename Cache<TT>::CvtFxn(),f))));
}
};
template <class T, class F>
struct ConsHelp2<T,F,odd_list<T>,true>
{
typedef typename boost::remove_reference<T>::type TT;
typedef odd_list<TT> L;
typedef typename L::force_result_type type;
static type go( const TT& x, const F& f ) {
return odd_list<TT>(x, list<TT>( ListRaw(), new Cache<T>(f) ));
}
};
template <class T, class F>
struct ConsHelp2<T,F,a_unique_type_for_nil,false>
{
typedef typename boost::remove_reference<T>::type TT;
typedef odd_list<TT> type;
static type go( const TT& x, const F& f ) {
return odd_list<TT>(x, list<TT>( ListRaw(), new Cache<T>(f) ));
}
};
template <class T, class L, bool b> struct ConsHelp1 {
typedef typename boost::remove_reference<T>::type TT;
typedef typename L::force_result_type type;
static type go( const TT& x, const L& l ) {
return type(x,l);
}
};
template <class T> struct ConsHelp1<T,a_unique_type_for_nil,false> {
typedef typename boost::remove_reference<T>::type TT;
typedef odd_list<TT> type;
static type go( const TT& x, const a_unique_type_for_nil& n ) {
return type(x,n);
}
};
template <class T, class F> struct ConsHelp1<T,F,false> {
// It's a function returning a list
// This is the one I have not fixed yet....
// typedef typename F::result_type L;
// typedef typename result_of::template ListType<F>::result_type L;
typedef odd_list<T> L;
typedef ConsHelp2<T,F,L,boost::is_base_and_derived<ListLike,L>::value> help;
typedef typename help::type type;
static type go( const T& x, const F& f ) {
return help::go(x,f);
}
};
template <class T, class L, bool b>
struct ConsHelp0;
template <class T>
struct ConsHelp0<T,a_unique_type_for_nil,true> {
typedef typename boost::remove_reference<T>::type TT;
typedef odd_list<T> type;
};
template <class T>
struct ConsHelp0<const T &,const a_unique_type_for_nil &,true> {
typedef typename boost::remove_reference<T>::type TT;
typedef odd_list<TT> type;
};
template <class T>
struct ConsHelp0<T &,a_unique_type_for_nil &,true> {
typedef typename boost::remove_reference<T>::type TT;
typedef odd_list<TT> type;
};
template <class T, class L>
struct ConsHelp0<T,L,false> {
// This removes any references from L for correct return type
// identification.
typedef typename boost::remove_reference<L>::type LType;
typedef typename ConsHelp1<T,LType,
boost::is_base_and_derived<ListLike,LType>::value>::type type;
};
/////////////////////////////////////////////////////////////////////
// cons (t,l) - cons a value to the front of a list.
// Note: The first arg, t, must be a value.
// The second arg, l, can be a list or NIL
// or a function that returns a list.
/////////////////////////////////////////////////////////////////////
struct Cons
{
/* template <class T, class L> struct sig : public fun_type<
typename ConsHelp1<T,L,
boost::is_base_and_derived<ListLike,L>::value>::type> {};
*/
template <typename Sig> struct result;
template <typename This, typename T, typename L>
struct result<This(T, L)>
{
typedef typename ConsHelp0<T,L,
listlike::detect_nil<L>::is_nil>::type type;
};
template <typename This, typename T>
struct result<This(T,a_unique_type_for_nil)>
{
typedef typename boost::remove_reference<T>::type TT;
typedef odd_list<TT> type;
};
template <typename T, typename L>
typename result<Cons(T,L)>::type
operator()( const T& x, const L& l ) const {
typedef typename result_of::ListType<L>::LType LType;
typedef ConsHelp1<T,LType,
boost::is_base_and_derived<ListLike,LType>::value> help;
return help::go(x,l);
}
template <typename T>
typename result<Cons(T,a_unique_type_for_nil)>::type
operator()( const T& x, const a_unique_type_for_nil &n ) const {
typedef typename result<Cons(T,a_unique_type_for_nil)>::type LL;
typedef ConsHelp1<T,LL,
boost::is_base_and_derived<ListLike,LL>::value> help;
return help::go(x,n);
}
};
}
typedef boost::phoenix::function<impl::Cons> Cons;
Cons cons;
namespace impl {
template <class L, class M, bool b>
struct CatHelp0;
template <class LL>
struct CatHelp0<LL,a_unique_type_for_nil,true> {
typedef typename result_of::template ListType<LL>::LType type;
};
template <class LL>
struct CatHelp0<const LL &,const a_unique_type_for_nil &,true> {
typedef typename result_of::template ListType<LL>::LType type;
//typedef L type;
};
template <class LL>
struct CatHelp0<LL &,a_unique_type_for_nil &,true> {
typedef typename result_of::template ListType<LL>::LType type;
//typedef L type;
};
template <class LL, class MM>
struct CatHelp0<LL,MM,false> {
// This removes any references from L for correct return type
// identification.
typedef typename result_of::template ListType<LL>::LType type;
// typedef typename ConsHelp1<T,LType,
// boost::is_base_and_derived<ListLike,LType>::value>::type type;
};
/////////////////////////////////////////////////////////////////////
// cat (l,m) - concatenate lists.
// Note: The first arg, l, must be a list or NIL.
// The second arg, m, can be a list or NIL
// or a function that returns a list.
/////////////////////////////////////////////////////////////////////
struct Cat
{
template <class L, class M, bool b, class R>
struct Helper /*: public c_fun_type<L,M,R>*/ {
template <typename Sig> struct result;
template <typename This>
struct result<This(L,M)>
{
typedef typename result_of::ListType<L>::tail_result_type type;
};
typedef R return_type;
R operator()( const L& l, const M& m,
reuser2<INV,VAR,INV,Helper,
typename result_of::template ListType<L>::tail_result_type,M>
r = NIL ) const {
if( null(l)() )
return m().force();
else
return cons( head(l)(), r( Helper<L,M,b,R>(), tail(l), m )() );
}
};
template <class L, class M, class R>
struct Helper<L,M,true,R> /*: public c_fun_type<L,M,R>*/ {
template <typename Sig> struct result;
template <typename This>
struct result<This(L,M)>
{
typedef typename result_of::ListType<L>::tail_result_type type;
};
typedef R return_type;
R operator()( const L& l, const M& m,
reuser2<INV,VAR,INV,Helper,
typename result_of::template ListType<L>::tail_result_type,M>
r = NIL ) const {
if( null(l)() )
return m.force();
else
return cons( head(l)(), r(Helper<L,M,true,R>(), tail(l), m )());
}
};
template <class L, class R>
struct Helper<L,a_unique_type_for_nil,false,R>
/*: public c_fun_type<L,
a_unique_type_for_nil,odd_list<typename L::value_type> > */
{
typedef odd_list<typename result_of::template ListType<L>::value_type> type;
odd_list<typename result_of::template ListType<L>::value_type>
operator()( const L& l, const a_unique_type_for_nil& ) const {
return l;
}
};
public:
/*template <class L, class M> struct sig : public fun_type<
typename RT<cons_type,typename L::value_type,M>::result_type>
{}; */
// Need to work out the return type here.
template <typename Sig> struct result;
template <typename This, typename L, typename M>
struct result<This(L,M)>
{
typedef typename CatHelp0<L,M,
listlike::detect_nil<M>::is_nil>::type type;
// typedef typename result_of::ListType<L>::tail_result_type type;
};
template <typename This, typename L>
struct result<This(L,a_unique_type_for_nil)>
{
typedef typename result_of::ListType<L>::tail_result_type type;
};
template <class L, class M>
typename result<Cat(L,M)>::type operator()( const L& l, const M& m ) const
{
listlike::EnsureListLike<L>();
return Helper<L,M,
boost::is_base_and_derived<typename listlike::ListLike,M>::value,
typename result<Cat(L,M)>::type>()(l,m);
}
template <class L>
typename result<Cat(L,a_unique_type_for_nil)>::type operator()( const L& l, const a_unique_type_for_nil& /* n */ ) const
{
listlike::EnsureListLike<L>();
return l;
}
};
}
typedef boost::phoenix::function<impl::Cat> Cat;
Cat cat;
//////////////////////////////////////////////////////////////////////
// Handy functions for making list literals
//////////////////////////////////////////////////////////////////////
// Yes, these aren't functoids, they're just template functions. I'm
// lazy and created these mostly to make it easily to make little lists
// in the sample code snippets that appear in papers.
struct UseList {
template <class T> struct List { typedef list<T> type; };
};
struct UseOddList {
template <class T> struct List { typedef odd_list<T> type; };
};
struct UseStrictList {
template <class T> struct List { typedef strict_list<T> type; };
};
template <class Kind = UseList>
struct list_with {
template <class T>
typename Kind::template List<T>::type
operator()( const T& a ) const {
typename Kind::template List<T>::type l;
l = cons( a, l );
return l;
}
template <class T>
typename Kind::template List<T>::type
operator()( const T& a, const T& b ) const {
typename Kind::template List<T>::type l;
l = cons( b, l );
l = cons( a, l );
return l;
}
template <class T>
typename Kind::template List<T>::type
operator()( const T& a, const T& b, const T& c ) const {
typename Kind::template List<T>::type l;
l = cons( c, l );
l = cons( b, l );
l = cons( a, l );
return l;
}
template <class T>
typename Kind::template List<T>::type
operator()( const T& a, const T& b, const T& c, const T& d ) const {
typename Kind::template List<T>::type l;
l = cons( d, l );
l = cons( c, l );
l = cons( b, l );
l = cons( a, l );
return l;
}
template <class T>
typename Kind::template List<T>::type
operator()( const T& a, const T& b, const T& c, const T& d,
const T& e ) const {
typename Kind::template List<T>::type l;
l = cons( e, l );
l = cons( d, l );
l = cons( c, l );
l = cons( b, l );
l = cons( a, l );
return l;
}
};
//////////////////////////////////////////////////////////////////////
}
}
#endif