286 questions
3
votes
2
answers
779
views
Using boost msm state machine with more than 50 transitions
MSMs transition table uses a mpl::vector. The default maximum size is 20.
You can change the size with
#define BOOST_MPL_CFG_NO_PREPROCESSED_HEADERS
#define BOOST_MPL_LIMIT_VECTOR_SIZE 50 ...
- 119
0
votes
1
answer
49
views
Boost metaparse how to return custom types
I'm trying to create a simple parser with metaparse to demonstrate how I can return my own custom types.
If I had a custom type ValNum, how can I integrate this into a basic parser such that it is ...
- 1,262
1
vote
0
answers
38
views
question about using mpl::range_c with mpl::fold
i have below simple function to convert a mpl::vector<...> to pack<...>
namespace mpl = boost::mpl;
template <typename... Ts>
struct pack{};
struct A{};
struct B{};
template <...
- 161
1
vote
1
answer
261
views
Use the value of strongly typed enum as index in boost::mpl::map
I am using a C++ map structure defined similar to std::map<Foo, std::any> for storing attributes of a compiler symbol table. The Foo is a strongly typed enum, such as enum class Foo {ENUM}. ...
- 75
3
votes
3
answers
501
views
Cartesian product of multiple templates
I have a few classes:
template <int,char>
class Foo{};
template <int,char>
class Bar{};
And I want to get all combinations with a few arguments, like this:
// {1, 2}, {'a', 'b'}
using ...
- 664
0
votes
2
answers
148
views
Using Custom Unary Predicates With boost::mpl::find_if in C++
I have a number of different class types each with the member function GetParameterString() which returns a string specific to the class. I'd like to be able to store these class types in a boost::mpl:...
- 1
0
votes
1
answer
173
views
Template metaprogramming - trying to implement Dimensional Analysis
For a better understanding and learning, I tried to use the boost mp11 library to implement the Dimensional Analysis from "C++ Template Metaprogramming" book (also found in the documentation ...
0
votes
0
answers
97
views
Boost mpl - append an element for each element in a vector
I have a boost mpl vector with types in it (obviously). I want to, after declaring this vector, iterate over it and append each type, wrapped in another template, to that vector. I have tried many ...
- 19.6k
1
vote
1
answer
227
views
Compile-time Size of Struct Minus Padding
I'm trying to use Boost MPL and Fusion to calculate the size of a struct exclusive of any padding. This is my current best attempt:
Live example
template<class T>
constexpr std::size_t ...
- 191
2
votes
2
answers
161
views
How to transform Parameter Pack into something else than std::tuple?
It is better explained by an example:
template <typename T1, typename T2>
struct OnePair
{
using TupleOfArgs = std::tuple<T1, T2>;
using TupleOfPairs = std::tuple<std::pair<...
- 633
0
votes
1
answer
237
views
Does std::variant provide functionality similar to boost::variant<>::types?
boost::variant exposes its list of variant types via boost::variant<>::types, which can be conveniently used with boost::mpl::for_each. std::variant is missing such a member.
I see std::...
- 1,507
0
votes
1
answer
158
views
Boost 1.61 header is trying to redefine mpl_::bool_
I'm on Boost 1.61 and compiling with clang 4.0.1 and I'm compiling for linux-gnu
Previously I was on Boost 1.52 and was not having this issue. Just by changing versions, I'm getting a compiler error ...
- 1,411
1
vote
1
answer
119
views
How to expand the content of an mpl::set as template parameters of a function template
I have a function template with a variadic number of template parameters:
template <typename T1, typename... Ts>
void doSomething()
{
...
}
Furthermore I have an mpl set defined as follows:...
- 121
0
votes
1
answer
1k
views
Replacing Boost MPL containers with C++17 features
I have some old code based on MPL containers, using enable_if to to activate some dispatch like this:
typedef boost::mpl::vector<std::int16_t, std::int32_t, int64_t, float, double, std::complex<...
- 22k
1
vote
0
answers
42
views
Will translation units built with different FUSION_MAX_VECTOR_SIZE (and similar) be linkable with each other?
I work on a large computational project that heavily use boost::mpl and boost:fusion on C++11.
Sometimes, in order to get some translation units to compile, I have to define the following BOOST ...
- 8,054
0
votes
2
answers
956
views
C++ map key to object
Hi is there a container where a key is a typename and value is an object/instance in boost or std???
What I want to achieve is I have a object pool for each data type and when I want to construct ...
- 469
3
votes
2
answers
223
views
Obtain regular MPL list from push_front operation
I am using Boost.MPL, I have a compile-time list (boost::mpl::list).
When I push back an element, I get something that is probably equivalent to a list but is not an boost::mpl::list.
#include <...
- 16.1k
4
votes
1
answer
254
views
Boost MPL Sorting Template Parameter Pack
The problem I'm trying to solve is to sort a template parameter pack according to the return value of a constexpr templated function specialized for each of the types I'm sorting.
I have a list of ...
- 149
0
votes
1
answer
65
views
MPL Map Instantiate Type
I have the following:
class Message
{
public:
bool process()
{
return doProcess();
}
protected:
virtual bool doProcess() = 0;
};
class Hello : public Message
{
protected:
...
- 463
-1
votes
1
answer
237
views
boost multi index convert index to tag and loop on indexes
I have a template class(CrMultiIndex) that receive a template parameter a definition of boost multi index(GlobalHash).I work with c++14
I need a way to translate index to tag(n_to_tag)? And to loop ...
- 383
1
vote
1
answer
80
views
Tag dispatching with transformed `boost::mpl::vector`s
I am trying to tag-dispatch into a function with a reversed copy of a boost::mpl::vector:
using InitOrder = boost::mpl::vector<
struct Foo,
struct Bar,
struct Baz
>;
template <...
- 63k
1
vote
1
answer
118
views
Can I use metaprogramming to transform a list of types into a new type that has specific implicit-conversion behavior to each type in the list?
I have a boost::mpl::vector containing several types, e.g.
typedef boost::mpl::vector<T1, T2, T3, T4> list_type;
For some known types T1, T2, T3, T4. Is there any way to use metaprogramming to ...
- 11.6k
1
vote
1
answer
214
views
How to get member type of boost::mpl placeholders during fold
Say there are two classes:
struct A
{
using Key = int;
using Value = char;
};
struct B
{
using Key = char;
using Value = float;
};
I want to use their member types to define the ...
- 3,312
1
vote
1
answer
2k
views
Calling a generic lambda in boost::mpl::for_each()
A few answers here (How to loop through a boost::mpl::list? being the one I started with) imply that I should be able to construct a generic lambda to feed to a boost::mpl::for_each() but I'm unable ...
- 137
0
votes
1
answer
240
views
boost MPL - doing transform on joint_view
Consider:
template<typename T>
struct MakeVectorOfType
{
typedef std::vector<T> type;
};
typedef boost::mpl::vector<int, double> TScalarTypes;
typedef boost::mpl::transform<...
- 19.6k
2
votes
1
answer
523
views
Using boost::mpl::find_if with custom predicate
Given
struct A {};
struct B {};
struct C {C(B) {}};
struct D : B {};
struct E {operator A() const {return A();}};
struct F {};
using AllowedTypes = boost::mpl::vector<A, C>;
I'm trying to ...
1
vote
2
answers
197
views
Assert if template parameter is allowed
I'm trying to limit a templated method to a given list of allowed types and their "repeated" flavour.
typedef boost::mpl::set<bool, int, double> allowedTypes;
class Foo
{
typedef boost::...
- 2,503
1
vote
0
answers
56
views
Boost MPL sequences and default parameters
I'm currently stuck on C++03, so variadic templates don't work for me.
I can do what I want with a limited number of arguments using boost::mpl::vector and boost::mpl::inherit_linearly, but I want to ...
- 178
1
vote
1
answer
283
views
Derive from `boost::static-visitor` to remove code duplication
In one of my projects I'm using boost-variant excessively. At some point I exceeded the maximum number of template parameters (20) for boost-variant. Hence, I derived the following solution by linking ...
- 6,064
5
votes
1
answer
1k
views
Getting all base classes [Meta-Programming]
Yesterday faced with problem how to get all base classes from some class.
For example:
class Object
{
public:
Object() = default;
};
class DerivedOne
: public Object
{
public:
DerivedOne() ...
- 882
3
votes
1
answer
912
views
How to simplify type generated by make_variant_over
Boost variant has a function called make_variant_over that takes an MPL sequence (for example list<A, B, C>) and produces a variant from those types.
However if one looks carefully the type ...
- 16.1k
3
votes
1
answer
438
views
Classify Types in Boost Variant using Visitor does not compile
I'm using boost-variant throughout my projects. In one scenario I need to classify the types contained in my boost-variant into several classes. As I have quite a lot of types in my variant I came up ...
- 6,064
0
votes
1
answer
98
views
How process knows when to stop listening for receive?
Consider a mesh whose bins are decomposed among processes. The numbers in the image are the ranks of processes.
At each time step, some of the points displace so that it is needed to send them to new ...
- 6,119
2
votes
1
answer
246
views
How do I merge two mpl maps producing a new map?
However I tweek the following code, there seems to be a point I am missing. It will not compile. I have two maps int -> int. I want to produce a third int -> int map containing all the key-value pairs ...
- 255
1
vote
0
answers
83
views
Boost MPL push_back all elements in one vector into another [duplicate]
Just starting to look at boost MPL, say I have 2 vectors that I want to combine, is it possible with the boost MPL or do I need to write the code myself?
Say I have:
typedef vector<Class0, Class1,...
- 3,940
1
vote
1
answer
879
views
Boost mpl::vector and hana
I'm searching some kind of meta vector/linked list. Seems like mpl::vector was the best way of doing this. But now there is hana. Unfortunately I can't find some kind of hana::vector. I saw an adapter ...
- 1,476
2
votes
1
answer
471
views
using boost mpl lambda with variadic template class
I am having a hard time understanding why the following simple program won't compile. I have a variadic template class (my_type below) which I want to use to transform an mpl vector. The following ...
- 3,813
1
vote
1
answer
178
views
boost accumulator_set: expect primary expression
I am a new to Boost library. I want a program that could compute the min, max, mean and variance of a distance vector (of type std::vector < double >) and I wrote the following code
std::vector ...
- 2,777
2
votes
1
answer
177
views
boost mpl count for simple example
I am trying to learn boost mpl, tried a very simple example to count the number of times a type appears in mpl map. Could somebody explain why the output of this program is 0
typedef map<
...
- 1,581
1
vote
1
answer
370
views
boost::mpl::equal is always false for vector and vector_c
I'm trying to reproduce the example "3.1 Dimensional Analysis" from the book "C++ Template Metaprogramming" by Abrahams and Gurtovoy. At some moment, they compare that the "dimensions" of a value (of ...
- 1,207
2
votes
2
answers
613
views
Boost Fusion: validate adapted struct member ordering at compile time
I'm using BOOST_FUSION_ADAPT_STRUCT(), and I need to check that all the members are declared and in the correct order. So first I did this:
template <typename Sequence>
struct checker
{
...
- 248k
0
votes
1
answer
283
views
Utilize boost-variant to create generic factory method with boost::mpl::for_each
In one of my projects I needed to map the int of the boost::variant which()-Function to the types of the boost::variant.
For some reasons the map doesn't contain the correct TVar Type? Why is that?
#...
- 6,064
7
votes
2
answers
2k
views
Creating a new boost-variant type from given nested boost-variant type
Assume that I have a nested boost::variant-type TNested containing some types and some other boost::variant types (that itself cannot contain again boost::variant types, so that there will be no ...
- 6,064
5
votes
1
answer
9k
views
C++ map of string as key and type as value
Is there an alternative to boost-hana in boost library which will allow me to create something like
typedef boost::AlterinativeToHana::map< make_pair<"abcd",ABCDType>,
...
- 1,975
2
votes
3
answers
1k
views
Get boost::variant's type index with boost::mpl
boost::variant has member types which is some kind of boost::mpl structure.
Is there a way to get an index of type in that structure at compile time, so late in in runtime i could do
if(...
- 118
2
votes
1
answer
709
views
Boost variant visitor with variadic template arguments
In one of my projects I'm actively using boost::variant and I stumbled upon a question I couldn't resolve on my own. I have a boost::variant that might contain atomic datatypes and STL containers of ...
- 6,064
1
vote
1
answer
229
views
boost::mpl::string size error messages
Here is the smaller version of a use case that I am working on.
#ifndef BOOST_MPL_LIMIT_STRING_SIZE
# define BOOST_MPL_LIMIT_STRING_SIZE 64
#endif
#include <boost/mpl/string.hpp>
#include <...
- 1,975
1
vote
1
answer
130
views
How to use nested metafunctions in Boost.MPL?
I have a simple metafunction:
template <typename T>
using is_const_lvalue_reference = mpl::and_<
std::is_lvalue_reference<T>,
std::is_const<typename std::remove_reference<...
- 7,800
1
vote
0
answers
48
views
Get subset of fusion::set with types from mpl::vector
Given a fusion::set and an mpl::vector, what's the easiest way to obtain a view of the set with types specified by the vector? Is there some built-in way to do it without manually writing index ...
- 7,800
4
votes
3
answers
933
views
Determining largest sizeof() in boost variant
Given:
boost::variant<T1,T2,T3,...,TN>
Calculate the following at compile time:
max(sizeof(T1), sizeof(T2), sizeof(T3),... ,sizeof(TN))
I had no idea how to approach this, but this answer ...
- 618