////////////////////////////////////////////////////////////////////////////
// lazy prelude.hpp
//
// Build lazy operations for Phoenix equivalents for FC++
//
// These are equivalents of the Boost FC++ functoids in prelude.hpp
//
// Usage: All of these are functors which need various numbers of arguments.
// Those can be supplied as real arguments or as Phoenix arguments.
// Execution will happen when all the arguments are supplied.
// e.g.
// take(2,list)() or take(2,arg1)(list)
//
// Implemented so far:
//
// id (moved back to operators.hpp)
//
// A lot of what comes here uses the list type, so that will be needed first.
//
// Now that list<T> is available I can start to build things here.
//
//
// until(pred,f,start) - if pred(start) is true, return start
// apply value = f(start)
// apply value = f(value)
// until pred(value) is true
// return value
//
// The predicate argument pred must be a lazy function taking one argument
// and returning bool.
// This can be a lazy function with an argument already.
// This has to be declared before the call to until.
// The type can be declated using Predicate as in this example:
//
// Predicate<int>::type f(greater(arg1,10));
// std::cout << until(f, inc, 1)() << std::endl;
//
// until2(pred,f,start,value2) - if pred(start,value2) is true, return start
// apply value1 = f(start)
// apply value1 = f(value1)
// until pred(value1,value2) is true
// return value1
//
// NOTE: until2 has been defined because this code does not support
// FC++ currying, so that a partial function cannot be passed
// as an argument. This provides a way of passing a second parameter.
// There is now the option to use Predicate<T> as shown above.
//
// odd(n) true if n is odd
// even(n) true if n is even
//
// last(list)
// all_but_last(list)
// at(list,n)
// length(list)
// filter(pred,list)
// iterate(function,value)
// repeat(value)
// take(n,list)
// drop(n,list)
// enum_from(x)
// enum_from_to(x,y)
//
////////////////////////////////////////////////////////////////////////////
// Interdependence:
// The old Boost FC++ has a set of headers which interelate and call each
// other in a complicated way. I am going to document the interdependence
// of the files here. I will then make sure that they are called correctly
// starting from this file. John Fletcher. February 2015.
////////////////////////////////////////////////////////////////////////////
// BoostFC++ header sequence:
//
// prelude.hpp -> list.hpp (optinally monad.hpp at end)
// list.hpp -> reuse.hpp
// reuse.hpp -> function.hpp
// function.hpp -> ref_count.hpp operator.hpp
// ref_count.hpp -> config.hpp boost headers and RefCountType definition
// operator.hpp -> lambda.hpp
// lambda.hpp -> full.hpp (use of lambda internals is optional)
// full.hpp -> smart.hpp curry.hpp pre_lambda.hpp (optionally full4.hpp)
// smart.hpp -> signature.hpp
// curry.hpp -> signature.hpp
// signature.hpp -> config.hpp
//
////////////////////////////////////////////////////////////////////////////
// Proposed order in lazy_prelude.hpp
// on the basis that files need what they call.
//
// lazy_config.hpp (If needed)* probably not needed.
// lazy_signature.hpp (If needed)*
// lazy_smart.hpp (If needed)*
// lazy_curry.hpp (If needed)*
// lazy_full.hpp (If needed)*
// lazy_operator.hpp (absorb definition of RefCountType)
// lazy_function.hpp (may not now be needed)
// lazy_reuse.hpp (implemented without use of FC++ functions)
// lazy_list.hpp
//
// * file does not yet exist.
////////////////////////////////////////////////////////////////////////////
// This is implemented such that no other lazy_ file calls other lazy_ files.
// They do call their own external files, which may well be duplicates.
// That can be sorted out later.
////////////////////////////////////////////////////////////////////////////
// Notes: full and curry operations should be covered by Phoenix.
// The lambda operations are quite different from Phoenix lambda
// and will be omitted.
// The implementation monad can be postponed.
// Some of function and reuse are needed for the list type.
// I will review later whether they are part of the external interface.
//
// 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)
==============================================================================*/
#ifndef BOOST_PHOENIX_FUNCTION_LAZY_PRELUDE
#define BOOST_PHOENIX_FUNCTION_LAZY_PRELUDE
#include <exception>
#include <vector>
#include <boost/phoenix/core.hpp>
#include <boost/phoenix/function.hpp>
#include <boost/phoenix/scope.hpp>
#include <boost/phoenix/operator.hpp>
#include <boost/phoenix/function/lazy_operator.hpp>
#include <boost/phoenix/function/lazy_reuse.hpp>
#include <boost/phoenix/function/lazy_list.hpp>
////////////////////////////////////////////////////////////////////////////
// To come here, the Haskell Prelude things which need list<T>.
// Things which do not need list<T> are in lazy_operator.hpp.
////////////////////////////////////////////////////////////////////////////
namespace boost {
namespace phoenix {
// These are in fcpp namespace as they introduce an FC++ style.
namespace fcpp {
template <typename T>
struct Predicate {
typedef typename boost::function1<bool,T> fun1_bool_T;
typedef typename boost::phoenix::function<fun1_bool_T> bool_F_T;
typedef bool_F_T type;
};
template <typename R>
struct Function0 {
typedef typename boost::function0<R> fun0_R;
typedef typename boost::phoenix::function<fun0_R> R_F;
typedef R_F type;
};
template <typename R,typename A0>
struct Function1 {
typedef typename boost::function1<R,A0> fun1_R_A0;
typedef typename boost::phoenix::function<fun1_R_A0> R_F_A0;
typedef R_F_A0 type;
};
template <typename R, typename A0, typename A1>
struct Function2 {
typedef typename boost::function2<R,A0,A1> fun2_R_A0_A1;
typedef typename boost::phoenix::function<fun2_R_A0_A1> R_F_A0_A1;
typedef R_F_A0_A1 type;
};
}
namespace impl {
using fcpp::INV;
using fcpp::VAR;
using fcpp::reuser1;
using fcpp::reuser2;
using fcpp::reuser3;
using boost::phoenix::arg_names::arg1;
struct Pow {
template <typename Sig>
struct result;
template <typename This, typename N, typename A0>
struct result<This(N,A0)>
: boost::remove_reference<A0>
{};
template <typename N, typename A0>
A0 operator()(N n, const A0 & a0,
reuser2<INV,VAR,INV,Pow,N,A0> r = NIL ) const {
if ( n <= 0 )
return A0(1);
else if ( n==1 )
return a0;
else {
A0 a1 = r( Pow(), n-1, a0)();
return a0*a1;
}
}
};
struct Apply {
template <typename Sig>
struct result;
template <typename This, typename N, typename F,typename A0>
struct result<This(N,F,A0)>
: boost::remove_reference<A0>
{};
template <typename N, typename F, typename A0>
A0 operator()(N n, const F &f, const A0 & a0,
reuser3<INV,VAR,INV,INV,Apply,N,F,A0> r = NIL ) const {
if ( n <= 0 )
return a0;
else if ( n==1 )
return f(arg1)(a0);
else {
A0 a1 = r( Apply(), n-1, f, a0)();
return f(a1)();
}
}
};
struct Odd {
template <typename Sig>
struct result;
template <typename This, typename T>
struct result<This(T)>
{
typedef bool type;
};
template <class T>
typename result<Odd(T)>::type operator()( const T& x ) const {
return x%2==1;
}
};
struct Even {
template <typename Sig>
struct result;
template <typename This, typename T>
struct result<This(T)>
{
typedef bool type;
};
template <class T>
typename result<Even(T)>::type operator()( const T& x ) const {
return x%2==0;
}
};
}
typedef boost::phoenix::function<impl::Pow> Pow;
typedef boost::phoenix::function<impl::Apply> Apply;
typedef boost::phoenix::function<impl::Odd> Odd;
typedef boost::phoenix::function<impl::Even> Even;
Pow pow;
Apply apply;
Odd odd;
Even even;
namespace impl {
using fcpp::INV;
using fcpp::VAR;
using fcpp::reuser1;
using fcpp::reuser2;
using fcpp::reuser3;
using boost::phoenix::arg_names::arg1;
// I cannot yet do currying to pass e.g. greater(9,arg1)
// as a function. This can be done using Predicate<T>::type.
struct Until {
template <typename Sig> struct result;
template <typename This, typename Pred, typename Unary, typename T>
struct result<This(Pred,Unary,T)>
: boost::remove_reference<T> {};
template <class Pred, class Unary, class T>
T operator()( const Pred& p,const Unary& op,const T &start) const
{
T tmp = start;
while( !p(tmp)() ) {
tmp = apply(1,op,tmp)();
}
return tmp;
}
};
struct Until2 {
template <typename Sig> struct result;
template <typename This, typename Binary, typename Unary,
typename T, typename X>
struct result<This(Binary,Unary,T,X)>
: boost::remove_reference<T> {};
template <class Binary, class Unary, class T, class X>
typename result<Until2(Binary,Unary,T,X)>::type
operator()( const Binary& p, const Unary& op, const T & start,
const X & check ) const
{
T tmp1 = start;
T tmp2;
while( !p(tmp1,check)() ) {
tmp2 = apply(1,op,tmp1)();
tmp1 = tmp2;
}
return tmp1;
}
};
struct Last {
template <typename Sig> struct result;
template <typename This, typename L>
struct result<This(L)>
{
typedef typename result_of::ListType<L>::value_type type;
};
template <class L>
typename result<Last(L)>::type
operator()( const L& ll ) const {
size_t x = 0;
typename result_of::ListType<L>::delay_result_type l = delay(ll);
while( !null( tail(l)() )() ) {
l = tail(l)();
++x;
#ifndef BOOST_PHOENIX_NO_LAZY_EXCEPTIONS
if (x > BOOST_PHOENIX_FUNCTION_MAX_LAZY_LIST_LENGTH)
break;
#endif
}
#ifndef BOOST_PHOENIX_NO_LAZY_EXCEPTIONS
if (x > BOOST_PHOENIX_FUNCTION_MAX_LAZY_LIST_LENGTH)
throw lazy_exception("Your list is too long!!");
#endif
return head(l)();
}
};
struct Init {
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 <class L>
typename result<Init(L)>::type
operator()( const L& l,
reuser1<INV,VAR,Init,
typename result_of::ListType<L>::delay_result_type>
r = NIL ) const {
if( null( tail( l )() )() )
return NIL;
else
return cons( head(l)(), r( Init(), tail(l)() )() )();
}
};
struct Length {
template <typename Sig> struct result;
template <typename This, typename L>
struct result<This(L)>
{
typedef size_t type;
};
template <class L>
size_t operator()( const L& ll ) const {
typename L::delay_result_type l = delay(ll);
size_t x = 0;
while( !null(l)() ) {
l = tail(l);
++x;
if (x > BOOST_PHOENIX_FUNCTION_MAX_LAZY_LIST_LENGTH)
break;
}
#ifndef BOOST_PHOENIX_NO_LAZY_EXCEPTIONS
if (x > BOOST_PHOENIX_FUNCTION_MAX_LAZY_LIST_LENGTH)
throw lazy_exception("Your list is too long!!");
#endif
return x;
}
};
// at is Haskell's operator (!!)
// This is zero indexed. at(l,0)() returns the first element.
struct At {
template <typename Sig> struct result;
template <typename This, typename L, typename N>
struct result<This(L,N)>
{
typedef typename result_of::ListType<L>::value_type type;
};
template <class L>
typename result<At(L,size_t)>::type
operator()( L l, size_t n ) const {
while( n!=0 ) {
l = tail(l);
--n;
}
return head(l)();
}
};
template <class P,class L>
struct FilterH
{
P p;
L l;
FilterH( const P& pp, const L& ll) : p(pp), l(ll) {}
template <typename Sig> struct result;
template <typename This, class PP, class LL>
struct result<This(PP,LL)>
{
typedef typename boost::phoenix::result_of::
ListType<LL>::delay_result_type type;
};
typename result<FilterH(P,L)>::type operator()() const {
typedef typename result_of::ListType<L>::
delay_result_type result_type;
typedef boost::function0<result_type> Fun2_R_P_L;
typedef boost::phoenix::function<Fun2_R_P_L> FilterH_R_P_L;
if (null(l)() )
return NIL;
Fun2_R_P_L fun2_R_P_L = FilterH<P,L>(p,tail(l));
FilterH_R_P_L filterh_R_P_L(fun2_R_P_L);
if( p(head(l))() )
return cons( head(l)(), filterh_R_P_L() );
else
return filterh_R_P_L();
}
};
struct Filter {
template <typename Sig> struct result;
template <typename This, typename P, typename L>
struct result<This(P,L)>
{
typedef typename result_of::ListType<L>::delay_result_type
type;
};
template <class P, class L>
typename result<Filter(P,L)>::type
operator()( const P& p, const L& ll) const
{
typename result_of::ListType<L>::delay_result_type
l = delay(ll);
typedef typename result_of::ListType<L>::
delay_result_type result_type;
typedef boost::function0<result_type> Fun2_R_P_L;
typedef boost::phoenix::function<Fun2_R_P_L> FilterH_R_P_L;
Fun2_R_P_L fun2_R_P_L = FilterH<P,L>(p,l);
FilterH_R_P_L filterh_R_P_L(fun2_R_P_L);
return filterh_R_P_L();
}
};
template <class F,class T>
struct IterateH
{
F f;
T t;
IterateH( const F& ff, const T& tt) : f(ff), t(tt) {}
template <typename Sig> struct result;
template <typename This,class F2,class T2>
struct result<This(F2,T2)>
{
typedef typename boost::remove_reference<T2>::type TT;
typedef typename boost::remove_const<TT>::type TTT;
typedef typename UseList::template List<TTT>::type LType;
typedef typename result_of::ListType<LType>::
delay_result_type type;
};
typename result<IterateH(F,T)>::type operator()() const {
typedef typename UseList::template List<T>::type LType;
typedef typename result_of::ListType<LType>::
delay_result_type result_type;
typedef boost::function0<result_type> Fun2_R_F_T;
typedef boost::phoenix::function<Fun2_R_F_T> IterateH_R_F_T;
Fun2_R_F_T fun2_R_F_T = IterateH<F,T>(f,f(t)());
IterateH_R_F_T iterateh_R_F_T(fun2_R_F_T);
return cons( t, iterateh_R_F_T() );
}
};
struct Iterate {
// Note: this does always return an odd_list; iterate() takes no ListLike
// parameter, and it requires that its result be lazy.
template <typename Sig> struct result;
template <typename This, typename F, typename T>
struct result<This(F,T)>
{
typedef typename boost::remove_reference<T>::type TT;
typedef typename boost::remove_const<TT>::type TTT;
typedef typename UseList::template List<TTT>::type LType;
typedef typename result_of::ListType<LType>::
delay_result_type type;
};
template <class F, class T>
typename result<Iterate(F,T)>::type operator()
(const F& f, const T& t) const {
typedef typename UseList::template List<T>::type LType;
typedef typename result_of::ListType<LType>::
delay_result_type result_type;
typedef boost::function0<result_type> Fun2_R_F_T;
typedef boost::phoenix::function<Fun2_R_F_T> IterateH_R_F_T;
Fun2_R_F_T fun2_R_F_T = IterateH<F,T>(f,f(t)());
IterateH_R_F_T iterateh_R_F_T(fun2_R_F_T);
return iterateh_R_F_T();
}
};
}
typedef boost::phoenix::function<impl::Until> Until;
typedef boost::phoenix::function<impl::Until2> Until2;
typedef boost::phoenix::function<impl::Last> Last;
typedef boost::phoenix::function<impl::Init> Init;
typedef boost::phoenix::function<impl::Length> Length;
typedef boost::phoenix::function<impl::At> At;
typedef boost::phoenix::function<impl::Filter> Filter;
typedef boost::phoenix::function<impl::Iterate> Iterate;
Until until;
Until2 until2;
Last last;
Init all_but_last; // renamed from init which is not available.
Length length;
At at_; //Renamed from at.
Filter filter;
Iterate iterate;
namespace impl {
struct Repeat {
// See note for iterate()
template <typename Sig> struct result;
template <typename This, typename T>
struct result<This(T)>
{
typedef typename boost::remove_reference<T>::type TT;
typedef typename boost::remove_const<TT>::type TTT;
typedef typename UseList::template List<TTT>::type LType;
typedef typename result_of::ListType<LType>::
delay_result_type type;
};
template <class T>
typename result<Repeat(T)>::type operator()( const T& x) const
{
return iterate(id,x);
}
};
struct Take {
template <typename Sig> struct result;
template <typename This, typename N, typename L>
struct result<This(N,L)>
{
typedef typename result_of::ListType<L>::force_result_type type;
};
template <class N,class L>
typename result<Take(N,L)>::type
operator()( N n, const L& l,
reuser2<INV,VAR,VAR,Take,N,
typename result_of::ListType<L>::force_result_type>
r = NIL
) const {
if( n <= 0 || null(l)() )
return NIL;
else {
return cons( head(l)(), r( Take(), n-1, tail(l)() )() )();
}
}
};
struct Drop {
template <typename Sig> struct result;
template <typename This, typename Dummy, typename L>
struct result<This(Dummy,L)>
{
typedef typename result_of::ListType<L>::delay_result_type type;
};
template <class L>
typename result<Drop(size_t,L)>::type
operator()( size_t n, const L& ll ) const {
typename L::delay_result_type l = delay(ll);
while( n!=0 && !null(l)() ) {
--n;
l = tail(l)();
}
return l;
}
};
template <class T>
struct EFH
{
mutable T x;
EFH( const T& xx) : x(xx) {}
template <typename Sig> struct result;
template <typename This, class TT>
struct result<This(TT)>
{
typedef typename boost::phoenix::UseList::template
List<TT>::type LType;
typedef typename boost::phoenix::result_of::
ListType<LType>::delay_result_type type;
};
typename result<EFH(T)>::type operator()() const {
typedef typename UseList::template List<T>::type LType;
typedef typename result_of::ListType<LType>::
delay_result_type result_type;
typedef boost::function0<result_type> fun1_R_TTT;
//std::cout << "EFH (" << x << ")" << std::endl;
++x;
fun1_R_TTT efh_R_TTT = EFH<T>(x);
typedef boost::phoenix::function<fun1_R_TTT> EFH_R_T;
EFH_R_T efh_R_T(efh_R_TTT);
#ifndef BOOST_PHOENIX_NO_LAZY_EXCEPTIONS
if (x > BOOST_PHOENIX_FUNCTION_MAX_LAZY_LIST_LENGTH)
throw lazy_exception("Running away in EFH!!");
#endif
return cons( x-1, efh_R_T() );
}
};
struct Enum_from {
template <typename Sig> struct result;
template <typename This, typename T>
struct result<This(T)>
{
typedef typename boost::remove_reference<T>::type TT;
typedef typename boost::remove_const<TT>::type TTT;
typedef typename UseList::template List<TTT>::type LType;
typedef typename result_of::ListType<LType>::
delay_result_type type;
};
template <class T>
typename result<Enum_from(T)>::type operator()
(const T & x) const
{
typedef typename boost::remove_reference<T>::type TT;
typedef typename boost::remove_const<TT>::type TTT;
typedef typename UseList::template List<T>::type LType;
typedef typename result_of::ListType<LType>::
delay_result_type result_type;
typedef boost::function0<result_type> fun1_R_TTT;
fun1_R_TTT efh_R_TTT = EFH<TTT>(x);
typedef boost::phoenix::function<fun1_R_TTT> EFH_R_T;
EFH_R_T efh_R_T(efh_R_TTT);
//std::cout << "enum_from (" << x << ")" << std::endl;
return efh_R_T();
}
};
template <class T>
struct EFTH
{
mutable T x;
T y;
EFTH( const T& xx, const T& yy) : x(xx), y(yy) {}
template <typename Sig> struct result;
template <typename This, class TT>
struct result<This(TT)>
{
typedef typename boost::phoenix::UseList::template
List<TT>::type LType;
typedef typename boost::phoenix::result_of::
ListType<LType>::delay_result_type type;
};
typename result<EFTH(T)>::type operator()() const {
typedef typename UseList::template List<T>::type LType;
typedef typename result_of::ListType<LType>::
delay_result_type result_type;
typedef boost::function0<result_type> fun1_R_TTT;
//std::cout << "EFTH (" << x << ")" << std::endl;
if (x > y ) return NIL;
++x;
fun1_R_TTT efth_R_TTT = EFTH<T>(x,y);
typedef boost::phoenix::function<fun1_R_TTT> EFTH_R_T;
EFTH_R_T efth_R_T(efth_R_TTT);
#ifndef BOOST_PHOENIX_NO_LAZY_EXCEPTIONS
if (x > BOOST_PHOENIX_FUNCTION_MAX_LAZY_LIST_LENGTH)
throw lazy_exception("Running away in EFTH!!");
#endif
return cons( x-1, efth_R_T() );
}
};
struct Enum_from_to {
template <typename Sig> struct result;
template <typename This, typename T>
struct result<This(T,T)>
{
typedef typename boost::remove_reference<T>::type TT;
typedef typename boost::remove_const<TT>::type TTT;
typedef typename UseList::template List<TTT>::type LType;
typedef typename result_of::ListType<LType>::
delay_result_type type;
};
template <class T>
typename result<Enum_from(T,T)>::type operator()
(const T & x, const T & y) const
{
typedef typename boost::remove_reference<T>::type TT;
typedef typename boost::remove_const<TT>::type TTT;
typedef typename UseList::template List<T>::type LType;
typedef typename result_of::ListType<LType>::
delay_result_type result_type;
typedef boost::function0<result_type> fun1_R_TTT;
fun1_R_TTT efth_R_TTT = EFTH<TTT>(x,y);
typedef boost::phoenix::function<fun1_R_TTT> EFTH_R_T;
EFTH_R_T efth_R_T(efth_R_TTT);
//std::cout << "enum_from (" << x << ")" << std::endl;
return efth_R_T();
}
};
}
//BOOST_PHOENIX_ADAPT_CALLABLE(apply, impl::apply, 3)
// Functors to be used in reuser will have to be defined
// using boost::phoenix::function directly
// in order to be able to be used as arguments.
typedef boost::phoenix::function<impl::Repeat> Repeat;
typedef boost::phoenix::function<impl::Take> Take;
typedef boost::phoenix::function<impl::Drop> Drop;
typedef boost::phoenix::function<impl::Enum_from> Enum_from;
typedef boost::phoenix::function<impl::Enum_from_to> Enum_from_to;
Repeat repeat;
Take take;
Drop drop;
Enum_from enum_from;
Enum_from_to enum_from_to;
namespace fcpp {
}
}
}
#endif