943 lines
31 KiB
C++

// This file is distributed under the BSD License.
// See "license.txt" for details.
// Copyright 2009-2012, Jonathan Turner (jonathan@emptycrate.com)
// Copyright 2009-2016, Jason Turner (jason@emptycrate.com)
// http://www.chaiscript.com
#ifndef CHAISCRIPT_PROXY_FUNCTIONS_HPP_
#define CHAISCRIPT_PROXY_FUNCTIONS_HPP_
#include <cassert>
#include <functional>
#include <memory>
#include <stdexcept>
#include <string>
#include <type_traits>
#include <vector>
#include <iterator>
#include "../chaiscript_defines.hpp"
#include "boxed_cast.hpp"
#include "boxed_value.hpp"
#include "proxy_functions_detail.hpp"
#include "type_info.hpp"
#include "dynamic_object.hpp"
namespace chaiscript {
class Type_Conversions;
namespace exception {
class bad_boxed_cast;
struct arity_error;
} // namespace exception
} // namespace chaiscript
namespace chaiscript
{
class Boxed_Number;
struct AST_Node;
typedef std::shared_ptr<AST_Node> AST_NodePtr;
namespace dispatch
{
template<typename FunctionType>
std::function<FunctionType> functor(std::shared_ptr<const Proxy_Function_Base> func, const Type_Conversions_State *t_conversions);
class Param_Types
{
public:
Param_Types()
: m_has_types(false),
m_doti(user_type<Dynamic_Object>())
{}
explicit Param_Types(const std::vector<Type_Info> &t_types)
: m_types(build_param_types(t_types)),
m_has_types(false),
m_doti(user_type<Dynamic_Object>())
{
}
explicit Param_Types(std::vector<std::pair<std::string, Type_Info>> t_types)
: m_types(std::move(t_types)),
m_has_types(false),
m_doti(user_type<Dynamic_Object>())
{
update_has_types();
}
static std::vector<std::pair<std::string, Type_Info>> build_param_types(const std::vector<Type_Info> &t_types)
{
std::vector<std::pair<std::string, Type_Info>> retval;
std::transform(t_types.begin(), t_types.end(), std::back_inserter(retval),
[](const Type_Info &ti){
return std::make_pair(std::string(), ti);
}
);
return retval;
}
void push_front(std::string t_name, Type_Info t_ti)
{
m_types.emplace(m_types.begin(), std::move(t_name), t_ti);
update_has_types();
}
bool operator==(const Param_Types &t_rhs) const
{
return m_types == t_rhs.m_types;
}
bool match(const std::vector<Boxed_Value> &vals, const Type_Conversions_State &t_conversions) const
{
if (!m_has_types) { return true; }
if (vals.size() != m_types.size()) { return false; }
for (size_t i = 0; i < vals.size(); ++i)
{
const auto &name = m_types[i].first;
if (!name.empty()) {
const auto &bv = vals[i];
if (bv.get_type_info().bare_equal(m_doti))
{
try {
const Dynamic_Object &d = boxed_cast<const Dynamic_Object &>(bv, &t_conversions);
return name == "Dynamic_Object" || d.get_type_name() == name;
} catch (const std::bad_cast &) {
return false;
}
} else {
const auto &ti = m_types[i].second;
if (!ti.is_undef())
{
if (!bv.get_type_info().bare_equal(ti)) {
return false;
}
} else {
return false;
}
}
}
}
return true;
}
const std::vector<std::pair<std::string, Type_Info>> &types() const
{
return m_types;
}
private:
void update_has_types()
{
for (const auto &type : m_types)
{
if (!type.first.empty())
{
m_has_types = true;
return;
}
}
m_has_types = false;
}
std::vector<std::pair<std::string, Type_Info>> m_types;
bool m_has_types;
Type_Info m_doti;
};
/**
* Pure virtual base class for all Proxy_Function implementations
* Proxy_Functions are a type erasure of type safe C++
* function calls. At runtime parameter types are expected to be
* tested against passed in types.
* Dispatch_Engine only knows how to work with Proxy_Function, no other
* function classes.
*/
class Proxy_Function_Base
{
public:
virtual ~Proxy_Function_Base() = default;
Boxed_Value operator()(const std::vector<Boxed_Value> &params, const chaiscript::Type_Conversions_State &t_conversions) const
{
if (m_arity < 0 || size_t(m_arity) == params.size()) {
return do_call(params, t_conversions);
} else {
throw exception::arity_error(static_cast<int>(params.size()), m_arity);
}
}
/// Returns a vector containing all of the types of the parameters the function returns/takes
/// if the function is variadic or takes no arguments (arity of 0 or -1), the returned
/// value contains exactly 1 Type_Info object: the return type
/// \returns the types of all parameters.
const std::vector<Type_Info> &get_param_types() const { return m_types; }
virtual bool operator==(const Proxy_Function_Base &) const = 0;
virtual bool call_match(const std::vector<Boxed_Value> &vals, const Type_Conversions_State &t_conversions) const = 0;
virtual bool is_attribute_function() const { return false; }
bool has_arithmetic_param() const
{
return m_has_arithmetic_param;
}
virtual std::vector<std::shared_ptr<const Proxy_Function_Base> > get_contained_functions() const
{
return std::vector<std::shared_ptr<const Proxy_Function_Base> >();
}
//! Return true if the function is a possible match
//! to the passed in values
bool filter(const std::vector<Boxed_Value> &vals, const Type_Conversions_State &t_conversions) const
{
assert(m_arity == -1 || (m_arity > 0 && static_cast<int>(vals.size()) == m_arity));
if (m_arity < 0)
{
return true;
} else if (m_arity > 1) {
return compare_type_to_param(m_types[1], vals[0], t_conversions) && compare_type_to_param(m_types[2], vals[1], t_conversions);
} else {
return compare_type_to_param(m_types[1], vals[0], t_conversions);
}
}
/// \returns the number of arguments the function takes or -1 if it is variadic
int get_arity() const
{
return m_arity;
}
static bool compare_type_to_param(const Type_Info &ti, const Boxed_Value &bv, const Type_Conversions_State &t_conversions)
{
if (ti.is_undef()
|| ti.bare_equal(user_type<Boxed_Value>())
|| (!bv.get_type_info().is_undef()
&& ( (ti.bare_equal(user_type<Boxed_Number>()) && bv.get_type_info().is_arithmetic())
|| ti.bare_equal(bv.get_type_info())
|| bv.get_type_info().bare_equal(user_type<std::shared_ptr<const Proxy_Function_Base> >())
|| t_conversions->converts(ti, bv.get_type_info())
)
)
)
{
return true;
} else {
return false;
}
}
virtual bool compare_first_type(const Boxed_Value &bv, const Type_Conversions_State &t_conversions) const
{
return compare_type_to_param(m_types[1], bv, t_conversions);
}
protected:
virtual Boxed_Value do_call(const std::vector<Boxed_Value> &params, const Type_Conversions_State &t_conversions) const = 0;
Proxy_Function_Base(std::vector<Type_Info> t_types, int t_arity)
: m_types(std::move(t_types)), m_arity(t_arity), m_has_arithmetic_param(false)
{
for (size_t i = 1; i < m_types.size(); ++i)
{
if (m_types[i].is_arithmetic())
{
m_has_arithmetic_param = true;
return;
}
}
}
static bool compare_types(const std::vector<Type_Info> &tis, const std::vector<Boxed_Value> &bvs,
const Type_Conversions_State &t_conversions)
{
if (tis.size() - 1 != bvs.size())
{
return false;
} else {
const size_t size = bvs.size();
for (size_t i = 0; i < size; ++i)
{
if (!compare_type_to_param(tis[i + 1], bvs[i], t_conversions)) { return false; }
}
}
return true;
}
std::vector<Type_Info> m_types;
int m_arity;
bool m_has_arithmetic_param;
};
}
/// \brief Common typedef used for passing of any registered function in ChaiScript
typedef std::shared_ptr<dispatch::Proxy_Function_Base> Proxy_Function;
/// \brief Const version of Proxy_Function. Points to a const Proxy_Function. This is how most registered functions
/// are handled internally.
typedef std::shared_ptr<const dispatch::Proxy_Function_Base> Const_Proxy_Function;
namespace exception
{
/// \brief Exception thrown if a function's guard fails
class guard_error : public std::runtime_error
{
public:
guard_error() noexcept
: std::runtime_error("Guard evaluation failed")
{ }
guard_error(const guard_error &) = default;
~guard_error() noexcept override = default;
};
}
namespace dispatch
{
class Dynamic_Function_Interface
{
public:
virtual ~Dynamic_Function_Interface() {}
virtual Param_Types get_dynamic_param_types() const = 0;
};
/**
* A Proxy_Function implementation that is not type safe, the called function
* is expecting a vector<Boxed_Value> that it works with how it chooses.
*/
class Dynamic_Proxy_Function : public Proxy_Function_Base, public Dynamic_Function_Interface
{
public:
Dynamic_Proxy_Function(
int t_arity=-1,
AST_NodePtr t_parsenode = AST_NodePtr(),
Param_Types t_param_types = Param_Types(),
Proxy_Function t_guard = Proxy_Function())
: Proxy_Function_Base(build_param_type_list(t_param_types), t_arity),
m_param_types(std::move(t_param_types)),
m_guard(std::move(t_guard)), m_parsenode(std::move(t_parsenode))
{
}
bool operator==(const Proxy_Function_Base &rhs) const override
{
const Dynamic_Proxy_Function *prhs = dynamic_cast<const Dynamic_Proxy_Function *>(&rhs);
return this == &rhs
|| ((prhs != nullptr)
&& this->m_arity == prhs->m_arity
&& !this->m_guard && !prhs->m_guard
&& this->m_param_types == prhs->m_param_types);
}
bool call_match(const std::vector<Boxed_Value> &vals, const Type_Conversions_State &t_conversions) const override
{
return (m_arity < 0 || (vals.size() == size_t(m_arity) && m_param_types.match(vals, t_conversions)))
&& test_guard(vals, t_conversions);
}
Proxy_Function get_guard() const
{
return m_guard;
}
AST_NodePtr get_parse_tree() const
{
return m_parsenode;
}
Param_Types get_dynamic_param_types() const override {
return m_param_types;
}
protected:
bool test_guard(const std::vector<Boxed_Value> &params, const Type_Conversions_State &t_conversions) const
{
if (m_guard)
{
try {
return boxed_cast<bool>((*m_guard)(params, t_conversions));
} catch (const exception::arity_error &) {
return false;
} catch (const exception::bad_boxed_cast &) {
return false;
}
} else {
return true;
}
}
private:
static std::vector<Type_Info> build_param_type_list(const Param_Types &t_types)
{
// For the return type
std::vector<Type_Info> types{chaiscript::detail::Get_Type_Info<Boxed_Value>::get()};
for (const auto &t : t_types.types())
{
if (t.second.is_undef()) {
types.push_back(chaiscript::detail::Get_Type_Info<Boxed_Value>::get());
} else {
types.push_back(t.second);
}
}
return types;
}
Param_Types m_param_types;
Proxy_Function m_guard;
AST_NodePtr m_parsenode;
};
template<typename Callable>
class Dynamic_Proxy_Function_Impl final : public Dynamic_Proxy_Function
{
public:
Dynamic_Proxy_Function_Impl(
Callable t_f,
int t_arity=-1,
AST_NodePtr t_parsenode = AST_NodePtr(),
Param_Types t_param_types = Param_Types(),
Proxy_Function t_guard = Proxy_Function())
: Dynamic_Proxy_Function(
t_arity,
std::move(t_parsenode),
std::move(t_param_types),
std::move(t_guard)
),
m_f(std::move(t_f))
{
}
protected:
Boxed_Value do_call(const std::vector<Boxed_Value> &params, const Type_Conversions_State &t_conversions) const override
{
if (call_match(params, t_conversions) && test_guard(params, t_conversions))
{
return m_f(params);
} else {
throw exception::guard_error();
}
}
private:
Callable m_f;
};
template<typename Callable, typename ... Arg>
Proxy_Function make_dynamic_proxy_function(Callable &&c, Arg&& ... a)
{
return chaiscript::make_shared<dispatch::Proxy_Function_Base, dispatch::Dynamic_Proxy_Function_Impl<Callable>>(
std::forward<Callable>(c), std::forward<Arg>(a)...);
}
/// An object used by Bound_Function to represent "_" parameters
/// of a binding. This allows for unbound parameters during bind.
struct Placeholder_Object
{
};
/// An implementation of Proxy_Function that takes a Proxy_Function
/// and substitutes bound parameters into the parameter list
/// at runtime, when call() is executed.
/// it is used for bind(function, param1, _, param2) style calls
class Bound_Function final : public Proxy_Function_Base
{
public:
Bound_Function(const Const_Proxy_Function &t_f,
const std::vector<Boxed_Value> &t_args)
: Proxy_Function_Base(build_param_type_info(t_f, t_args), (t_f->get_arity()<0?-1:static_cast<int>(build_param_type_info(t_f, t_args).size())-1)),
m_f(t_f), m_args(t_args)
{
assert(m_f->get_arity() < 0 || m_f->get_arity() == static_cast<int>(m_args.size()));
}
bool operator==(const Proxy_Function_Base &t_f) const override
{
return &t_f == this;
}
bool call_match(const std::vector<Boxed_Value> &vals, const Type_Conversions_State &t_conversions) const override
{
return m_f->call_match(build_param_list(vals), t_conversions);
}
std::vector<Const_Proxy_Function> get_contained_functions() const override
{
return std::vector<Const_Proxy_Function>{m_f};
}
std::vector<Boxed_Value> build_param_list(const std::vector<Boxed_Value> &params) const
{
auto parg = params.begin();
auto barg = m_args.begin();
std::vector<Boxed_Value> args;
while (!(parg == params.end() && barg == m_args.end()))
{
while (barg != m_args.end()
&& !(barg->get_type_info() == chaiscript::detail::Get_Type_Info<Placeholder_Object>::get()))
{
args.push_back(*barg);
++barg;
}
if (parg != params.end())
{
args.push_back(*parg);
++parg;
}
if (barg != m_args.end()
&& barg->get_type_info() == chaiscript::detail::Get_Type_Info<Placeholder_Object>::get())
{
++barg;
}
}
return args;
}
protected:
static std::vector<Type_Info> build_param_type_info(const Const_Proxy_Function &t_f,
const std::vector<Boxed_Value> &t_args)
{
assert(t_f->get_arity() < 0 || t_f->get_arity() == static_cast<int>(t_args.size()));
if (t_f->get_arity() < 0) { return std::vector<Type_Info>(); }
const auto types = t_f->get_param_types();
assert(types.size() == t_args.size() + 1);
// this analysis warning is invalid in MSVC12 and doesn't exist in MSVC14
std::vector<Type_Info> retval{types[0]};
for (size_t i = 0; i < types.size() - 1; ++i)
{
if (t_args[i].get_type_info() == chaiscript::detail::Get_Type_Info<Placeholder_Object>::get())
{
retval.push_back(types[i+1]);
}
}
return retval;
}
Boxed_Value do_call(const std::vector<Boxed_Value> &params, const Type_Conversions_State &t_conversions) const override
{
return (*m_f)(build_param_list(params), t_conversions);
}
private:
Const_Proxy_Function m_f;
std::vector<Boxed_Value> m_args;
};
class Proxy_Function_Impl_Base : public Proxy_Function_Base
{
public:
explicit Proxy_Function_Impl_Base(const std::vector<Type_Info> &t_types)
: Proxy_Function_Base(t_types, static_cast<int>(t_types.size()) - 1)
{
}
bool call_match(const std::vector<Boxed_Value> &vals, const Type_Conversions_State &t_conversions) const override
{
return static_cast<int>(vals.size()) == get_arity()
&& (compare_types(m_types, vals, t_conversions) && compare_types_with_cast(vals, t_conversions));
}
virtual bool compare_types_with_cast(const std::vector<Boxed_Value> &vals, const Type_Conversions_State &t_conversions) const = 0;
};
/// For any callable object
template<typename Func, typename Callable>
class Proxy_Function_Callable_Impl final : public Proxy_Function_Impl_Base
{
public:
explicit Proxy_Function_Callable_Impl(Callable f)
: Proxy_Function_Impl_Base(detail::build_param_type_list(static_cast<Func *>(nullptr))),
m_f(std::move(f))
{
}
bool compare_types_with_cast(const std::vector<Boxed_Value> &vals, const Type_Conversions_State &t_conversions) const override
{
return detail::compare_types_cast(static_cast<Func *>(nullptr), vals, t_conversions);
}
bool operator==(const Proxy_Function_Base &t_func) const override
{
return dynamic_cast<const Proxy_Function_Callable_Impl<Func, Callable> *>(&t_func) != nullptr;
}
protected:
Boxed_Value do_call(const std::vector<Boxed_Value> &params, const Type_Conversions_State &t_conversions) const override
{
return detail::call_func(detail::Function_Signature<Func>(), m_f, params, t_conversions);
}
private:
Callable m_f;
};
class Assignable_Proxy_Function : public Proxy_Function_Impl_Base
{
public:
explicit Assignable_Proxy_Function(const std::vector<Type_Info> &t_types)
: Proxy_Function_Impl_Base(t_types)
{
}
virtual void assign(const std::shared_ptr<const Proxy_Function_Base> &t_rhs) = 0;
};
template<typename Func>
class Assignable_Proxy_Function_Impl final : public Assignable_Proxy_Function
{
public:
Assignable_Proxy_Function_Impl(std::reference_wrapper<std::function<Func>> t_f, std::shared_ptr<std::function<Func>> t_ptr)
: Assignable_Proxy_Function(detail::build_param_type_list(static_cast<Func *>(nullptr))),
m_f(std::move(t_f)), m_shared_ptr_holder(std::move(t_ptr))
{
assert(!m_shared_ptr_holder || m_shared_ptr_holder.get() == &m_f.get());
}
bool compare_types_with_cast(const std::vector<Boxed_Value> &vals, const Type_Conversions_State &t_conversions) const override
{
return detail::compare_types_cast(static_cast<Func *>(nullptr), vals, t_conversions);
}
bool operator==(const Proxy_Function_Base &t_func) const override
{
return dynamic_cast<const Assignable_Proxy_Function_Impl<Func> *>(&t_func) != nullptr;
}
std::function<Func> internal_function() const
{
return m_f.get();
}
void assign(const std::shared_ptr<const Proxy_Function_Base> &t_rhs) override {
m_f.get() = dispatch::functor<Func>(t_rhs, nullptr);
}
protected:
Boxed_Value do_call(const std::vector<Boxed_Value> &params, const Type_Conversions_State &t_conversions) const override
{
return detail::call_func(detail::Function_Signature<Func>(), m_f.get(), params, t_conversions);
}
private:
std::reference_wrapper<std::function<Func>> m_f;
std::shared_ptr<std::function<Func>> m_shared_ptr_holder;
};
/// Attribute getter Proxy_Function implementation
template<typename T, typename Class>
class Attribute_Access final : public Proxy_Function_Base
{
public:
explicit Attribute_Access(T Class::* t_attr)
: Proxy_Function_Base(param_types(), 1),
m_attr(t_attr)
{
}
bool is_attribute_function() const override { return true; }
bool operator==(const Proxy_Function_Base &t_func) const override
{
const Attribute_Access<T, Class> * aa
= dynamic_cast<const Attribute_Access<T, Class> *>(&t_func);
if (aa) {
return m_attr == aa->m_attr;
} else {
return false;
}
}
bool call_match(const std::vector<Boxed_Value> &vals, const Type_Conversions_State &) const override
{
if (vals.size() != 1)
{
return false;
}
return vals[0].get_type_info().bare_equal(user_type<Class>());
}
protected:
Boxed_Value do_call(const std::vector<Boxed_Value> &params, const Type_Conversions_State &t_conversions) const override
{
const Boxed_Value &bv = params[0];
if (bv.is_const())
{
const Class *o = boxed_cast<const Class *>(bv, &t_conversions);
return do_call_impl<T>(o);
} else {
Class *o = boxed_cast<Class *>(bv, &t_conversions);
return do_call_impl<T>(o);
}
}
private:
template<typename Type>
auto do_call_impl(Class *o) const -> std::enable_if_t<std::is_pointer<Type>::value, Boxed_Value>
{
return detail::Handle_Return<Type>::handle(o->*m_attr);
}
template<typename Type>
auto do_call_impl(const Class *o) const -> std::enable_if_t<std::is_pointer<Type>::value, Boxed_Value>
{
return detail::Handle_Return<const Type>::handle(o->*m_attr);
}
template<typename Type>
auto do_call_impl(Class *o) const -> std::enable_if_t<!std::is_pointer<Type>::value, Boxed_Value>
{
return detail::Handle_Return<typename std::add_lvalue_reference<Type>::type>::handle(o->*m_attr);
}
template<typename Type>
auto do_call_impl(const Class *o) const -> std::enable_if_t<!std::is_pointer<Type>::value, Boxed_Value>
{
return detail::Handle_Return<typename std::add_lvalue_reference<typename std::add_const<Type>::type>::type>::handle(o->*m_attr);
}
static std::vector<Type_Info> param_types()
{
return {user_type<T>(), user_type<Class>()};
}
T Class::* m_attr;
};
}
namespace exception
{
/// \brief Exception thrown in the case that a method dispatch fails
/// because no matching function was found
///
/// May be thrown due to an arity_error, a guard_error or a bad_boxed_cast
/// exception
class dispatch_error : public std::runtime_error
{
public:
dispatch_error(std::vector<Boxed_Value> t_parameters,
std::vector<Const_Proxy_Function> t_functions)
: std::runtime_error("Error with function dispatch"), parameters(std::move(t_parameters)), functions(std::move(t_functions))
{
}
dispatch_error(std::vector<Boxed_Value> t_parameters,
std::vector<Const_Proxy_Function> t_functions,
const std::string &t_desc)
: std::runtime_error(t_desc), parameters(std::move(t_parameters)), functions(std::move(t_functions))
{
}
dispatch_error(const dispatch_error &) = default;
~dispatch_error() noexcept override = default;
std::vector<Boxed_Value> parameters;
std::vector<Const_Proxy_Function> functions;
};
}
namespace dispatch
{
namespace detail
{
template<typename FuncType>
bool types_match_except_for_arithmetic(const FuncType &t_func, const std::vector<Boxed_Value> &plist,
const Type_Conversions_State &t_conversions)
{
const std::vector<Type_Info> &types = t_func->get_param_types();
if (t_func->get_arity() == -1) { return false; }
assert(plist.size() == types.size() - 1);
return std::mismatch(plist.begin(), plist.end(),
types.begin()+1,
[&](const Boxed_Value &bv, const Type_Info &ti) {
return Proxy_Function_Base::compare_type_to_param(ti, bv, t_conversions)
|| (bv.get_type_info().is_arithmetic() && ti.is_arithmetic());
}
) == std::make_pair(plist.end(), types.end());
}
template<typename InItr, typename Funcs>
Boxed_Value dispatch_with_conversions(InItr begin, const InItr &end, const std::vector<Boxed_Value> &plist,
const Type_Conversions_State &t_conversions, const Funcs &t_funcs)
{
InItr matching_func(end);
while (begin != end)
{
if (types_match_except_for_arithmetic(begin->second, plist, t_conversions))
{
if (matching_func == end)
{
matching_func = begin;
} else {
// handle const members vs non-const member, which is not really ambiguous
const auto &mat_fun_param_types = matching_func->second->get_param_types();
const auto &next_fun_param_types = begin->second->get_param_types();
if (plist[0].is_const() && !mat_fun_param_types[1].is_const() && next_fun_param_types[1].is_const()) {
matching_func = begin; // keep the new one, the const/non-const matchup is correct
} else if (!plist[0].is_const() && !mat_fun_param_types[1].is_const() && next_fun_param_types[1].is_const()) {
// keep the old one, it has a better const/non-const matchup
} else {
// ambiguous function call
throw exception::dispatch_error(plist, std::vector<Const_Proxy_Function>(t_funcs.begin(), t_funcs.end()));
}
}
}
++begin;
}
if (matching_func == end)
{
// no appropriate function to attempt arithmetic type conversion on
throw exception::dispatch_error(plist, std::vector<Const_Proxy_Function>(t_funcs.begin(), t_funcs.end()));
}
std::vector<Boxed_Value> newplist;
newplist.reserve(plist.size());
const std::vector<Type_Info> &tis = matching_func->second->get_param_types();
std::transform(tis.begin() + 1, tis.end(),
plist.begin(),
std::back_inserter(newplist),
[](const Type_Info &ti, const Boxed_Value &param) -> Boxed_Value {
if (ti.is_arithmetic() && param.get_type_info().is_arithmetic()
&& param.get_type_info() != ti) {
return Boxed_Number(param).get_as(ti).bv;
} else {
return param;
}
}
);
try {
return (*(matching_func->second))(newplist, t_conversions);
} catch (const exception::bad_boxed_cast &) {
//parameter failed to cast
} catch (const exception::arity_error &) {
//invalid num params
} catch (const exception::guard_error &) {
//guard failed to allow the function to execute
}
throw exception::dispatch_error(plist, std::vector<Const_Proxy_Function>(t_funcs.begin(), t_funcs.end()));
}
}
/**
* Take a vector of functions and a vector of parameters. Attempt to execute
* each function against the set of parameters, in order, until a matching
* function is found or throw dispatch_error if no matching function is found
*/
template<typename Funcs>
Boxed_Value dispatch(const Funcs &funcs,
const std::vector<Boxed_Value> &plist, const Type_Conversions_State &t_conversions)
{
std::vector<std::pair<size_t, const Proxy_Function_Base *>> ordered_funcs;
ordered_funcs.reserve(funcs.size());
const constexpr auto boxed_type = user_type<Boxed_Value>();
const constexpr auto dynamic_type = user_type<Dynamic_Object>();
for (const auto &func : funcs)
{
const auto arity = func->get_arity();
if (arity == -1)
{
ordered_funcs.emplace_back(plist.size(), func.get());
} else if (arity == static_cast<int>(plist.size())) {
size_t numdiffs = 0;
for (size_t i = 0; i < plist.size(); ++i)
{
const auto &p_type = plist[i].get_type_info();
const auto &f_type = func->get_param_types()[i+1];
if (!(f_type.bare_equal(boxed_type) && p_type.bare_equal(dynamic_type)) && !f_type.bare_equal(p_type))
{
++numdiffs;
}
}
ordered_funcs.emplace_back(numdiffs, func.get());
}
}
for (size_t i = 0; i <= plist.size(); ++i)
{
for (const auto &func : ordered_funcs )
{
try {
if (func.first == i && (i == 0 || func.second->filter(plist, t_conversions)))
{
return (*(func.second))(plist, t_conversions);
}
} catch (const exception::bad_boxed_cast &) {
//parameter failed to cast, try again
} catch (const exception::arity_error &) {
//invalid num params, try again
} catch (const exception::guard_error &) {
//guard failed to allow the function to execute,
//try again
}
}
}
return detail::dispatch_with_conversions(ordered_funcs.cbegin(), ordered_funcs.cend(), plist, t_conversions, funcs);
}
}
}
#endif