ParameterPack< T > Struct Template Reference

#include <apibase.h>

Detailed Description

template<typename... T>
struct maxon::ParameterPack< T >

Helper class to work with parameter packs. IndexOf supports finding the index of a type in the argument list, At supports indexing into the list, ContainsAll implements a subset test:

ParameterPack<Int, Float, String, String>::IndexOf<Float>::value == 1
ParameterPack<Int, Float, String, String>::At<2>::type == String
ParameterPack<Int, Float, String, String>::ContainsAll<String, Int>::value == true

Template Parameters

T	The types of the parameter pack.

Classes
struct	At
struct	IndexOf

Public Types
using	FirstType = void
using	RestPack = ParameterPack<>
template<typename... X>
using	ContainsAll = maxon::details::ParameterPackContainsAll< ParameterPack, X... >
template<template< typename... > class TEMPLATE, typename... X>
using	Apply = TEMPLATE< X... >
template<template< typename... > class TEMPLATE, typename... X>
using	ApplyAppend = TEMPLATE< X... >
template<typename... X>
using	Append = ParameterPack< X... >
template<typename PACK >
using	AppendPack = PACK

Static Public Member Functions
template<Int OFFSET = 0, typename LAMBDA >
static ResultOk< void >	ForEach (const LAMBDA &lambda)

Static Public Attributes
static constexpr Int	COUNT

Member Typedef Documentation

FirstType

using FirstType = void

The first type of this parameter pack.

RestPack

using RestPack = ParameterPack<>

ContainsAll

using ContainsAll = maxon::details::ParameterPackContainsAll<ParameterPack, X...>

ContainsAll checks if this parameter pack contains all types X. Besides a list of types X can also be a ParameterPack itself.

ParameterPack<Int, Float, String, String>::ContainsAll<String, Int>::value == true
ParameterPack<Int, Float, String, String>::ContainsAll<ParameterPack<String, Int>>::value == true
ParameterPack<Int, Float, String, String>::ContainsAll<String, Int, Bool>::value == false

Template Parameters

X	Types to check. This can either be a list of types, or a single ParameterPack.

Apply

using Apply = TEMPLATE<X...>

ApplyAppend

using ApplyAppend = TEMPLATE<X...>

Append

using Append = ParameterPack<X...>

A type alias for a ParameterPack of the types T... and X... I.e., ParameterPack<T...>::Append<X...> is an alias for ParameterPack<T..., X...>.

Template Parameters

X	Types to append to this ParameterPack.

AppendPack

using AppendPack = PACK

A type alias for a ParameterPack of the types of this ParameterPack and PACK. I.e., ParameterPack<T...>::AppendPack<ParameterPack<X...>> is an alias for ParameterPack<T..., X...>.

Template Parameters

PACK	Another ParameterPack to append to this ParameterPack.

Member Function Documentation

ForEach()

static ResultOk<void> ForEach ( const LAMBDA &  lambda )

static

Calls lambda for each type of the parameterpack. lambda is called with a single argument of a type which has index and type members and also a constexpr conversion function to Int which returns the index. member type alias of name #type:

Pack::ForEach(
  [] (auto i) -> Result<void>
  {
    iferr_scope;
    using T = typename decltype(i)::type; // This gives the type of the current parameter pack member.
    constexpr Int index = decltype(i)::index; // This gives the index of the current parameter pack member.
    constexpr Int index2 = i; // Another way to get the index.
    ...
    return OK;
  }) iferr_return;

Parameters

[in]

lambda

Index within the parameter pack.

Member Data Documentation

COUNT

constexpr Int COUNT

staticconstexpr

The number of types of this parameter pack.