Questions tagged [template-meta-programming]
For code that uses templates to generate compile-time executed code. For ordinary use of templates, use the 'template' tag instead.
277 questions
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Namespace-scope try_lock_for / try_lock_until pt. 2
This is my second iteration of implementing try_lock_for/try_lock_until function templates in which I've cherry-picked a bunch ...
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4
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2
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124
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Implementing views and slicing for arbitrarily nested `std::vector`s in a header-only library
I implemented a templated vector_view class that holds a reference to an std::vector and provides the following operations:
...
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236
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A generic function that reads a line of numeric values from a file
I'm writing a library of IO functions for my physics laboratory class. In the meanwhile, I'm hoping to learn more about generic programming and C++20 concepts.
Some context
I usually came home from ...
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1
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113
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2
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117
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Member detection within a class
Needed to do some Meta programming.
I needed to check if a class has a specific member (one case a member variable second case a member type (two distinct use cases)).
Since I am writing a library, I ...
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4
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503
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Compile time string manipulation in C++
I recently had to work on some conversion of literal strings and wondered if that could be done at compile time using template meta programming. I couldn't find many examples online, so I started ...
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256
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Function composition in the context of data processing pipelines
Prior Notification
This follows a previous review of mine that addressed the core helper function named make_skippable.
The composition implementation presented ...
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3
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182
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Extending callable signature with std::optional in context of function composition (make_skippable)
(Please note: the post about the compose implementation announced below is now available.)
This is about decorating callables by making their argument and return value to be a ...
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127
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(C++) Template code for adding tagging types to add additional context
Below is a piece of template code which allows for adding a Tag to structure or class types.
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191
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C++ printing library with templates
I was mad C++ did not have support for printing containers. I also could not find a header only library for printing containers so I decided to make my own. My goals were: 1) practicing templates 2) ...
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3
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1
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172
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Partial specialization of class template with minimal code duplication
I have a class template that stores an std::optional<T>. A very reduced version of the class template looks like this:
...
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2
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1
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267
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Template for making distinct numeric type aliases
I've tried to make a small template for the creation of distinct (incompatible) numerical types. For example both row and column indices are usually represented as the same underlying type. However it ...
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C++ enum to string conversion utility
I needed to find a way to convert a bunch of enums to string for displaying in C++. The two main ways I found when searching was using dark magic macros or voodoo magic template metaprogramming.
As I ...
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68
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Variadic pack class providing operations over types without constructing objects of those types
Sometimes I find I want to call a function passing each of a set of types as a template parameter, but without needing to construct an object of those types. I also may want to do this in multiple ...
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253
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Transpose types variadicly
I want to do template metaprogramming to compute the conversion from std::variant<Ts...> to ...
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1
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121
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scoped timer class (3rd revision)
Again, here is the previous question. I have (re)revised my custom scoped timer using the valuable feedback I got from a helpful member of this community. However I feel the need to ask this question ...
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Is there a more elegant solution to store and process different types using templates? [closed]
I'm trying to create some system for profiling and I need to track different data types (double, float int). I have a container that can hold some base type, and then perform actions on the concrete ...
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Template to unpack arguments to a std::function
I am writing some C++ code to interact with an external scripting language. I want to be able to register arbitrary C++ callable code as functions to be called from the script.
The scripting library ...
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3
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661
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C++: Visit Any Type Holding Other Types (`std::any`, `std::variant`, etc.)
Intro
I want to visit the value held by a class, which could be of multiple types. This class is very similar to a std::any, so I will be using this in this ...
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221
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C++17 view over the Ith elements of tuples in containers of tuples
For mainly didactic reasons, I have designed my ElementsView<I, T> class template, which provides a view over the I th ...
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2
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117
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C++ variardic universal template for unknown types, used to handle multiple network protocols
I am creating a template function with variardic arguments, to handle a specific classes that have some interface, method, member or whatever is specialized in a specialization area. However I came to ...
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2k
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visit for std::any
While solving an online excersise I have written some basic implementation for a visit function that works with std::any.
The ...
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1
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771
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Binding move-only objects to functions (for a thread pool implementation)
I recently implemented a thread pool using std::functions. I only supported functions taking no arguments on the assumption that there would be no need to have them ...
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3k
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Mapping between Enum <-> Enum <-> String view
I've been working on some kind of mapper that would allow me to map between types.
My objectives:
it should allow mapping between two enums
it should allow mapping enum to string_view
it should allow ...
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389
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An rough implementation of `std::is_constructible`
As a challenge/fun activity/task, I have implemented my version of std::is_constructible.
Here is the source code:
...
2
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349
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Implementation of versatile IIR digital filter in C++
I have realized that all the digital filters of the IIR type have the same structure. They are described by difference equation in following form:
$$
y(k) = b_0\cdot x(k) + b_1\cdot x(k-1) + \ldots +...
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204
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invocable_traits v5
Goal: implement traits that for anything callable return its arity, return type and the argument types. Since pointers to data members are also callable, those should be handled (and be considered 0-...
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240
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invocable_traits v4
Update: there is a new version of this code: v5 is posted here
Goal: implement traits that for anything callable return its arity, return type and the argument types. Since pointers to data members ...
3
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81
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invocable_traits v3
Update: there is a new version of this code: v4 is posted here
Goal: implement traits that for anything callable return its arity, return type and the argument types. Since pointers to data members ...
3
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1
answer
107
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invocable_traits
Update: there are new versions of this code: v3 is posted here and v4 is posted here
Goal: implement traits that for anything callable return its arity, return type and the argument types. Since ...
4
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1
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1k
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c++20 compile time string utility v2
This is a follow up on c++20 compile time string utility, as suggested by G. Sliepen posted as a new question, so it can be reviewed on its own.
The following code has suggested improvements from the ...
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c++20 compile time string utility
While upgrading some meta-program running in production for years to the latest (c++20) standard, I rewrote this particular compile time string utility.
Even though this new version produces desired ...
- 95
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2
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957
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Automatically registering a class using header-only templated classes
I'm trying to reduce the boilerplate of a lot of header-only classes I'm using. Each of these classes must go through a registration step. I want this step to be defined in the same file as the class ...
- 621
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156
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One-time dynamic, many-time *almost* static type dispatch
Annoyed at the tension between good software design principles that require well-defined delimitations between interface and implementations, and the requirements for critical code to run fast, which ...
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C++17 : Typelist manipulation
I'm reading "Modern C++ Design"(A. Alexandrescu, 2002) and practicing basic TMP in chapter 3. Typelists. Since the book is quite dated, I revised example codes in C++17-esque manner.
Feel ...
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991
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template function for conditional dereference
I don't know why there's no such function in std (at least I didn't find one). I need a conditional template function to return a reference to an object of T. ...
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1k
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Object to ignore unused function output parameters
In our software we have some functions that return information through lvalue reference parameters, which, in some cases, are irrelevant for the calling code. For that reason, I tried to come up with ...
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443
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Handle C++ templates in Qt5
Searching for a solution to my problem I've read many posts regarding templates in Qt (including those on SE) and didn't find a complete solution (or I should say a complete example of a solution) so ...
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623
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Implementing apply_each for tuple c++
I'm implementing apply_each for tuple-like object as a general function which may be a combined version of for_each and ...
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2
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1
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319
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Creating a structural type array wrapper to be qualified as non-type template parameter C++
I'm trying to replicate std::array but with modifications that I should put the private data member to the public so the class template ...
- 195
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1
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136
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Computing nth Tribonacci number at compile time using C++ template metaprogramming facilities
I have this small C++ program for computing the \$n\$th Tribonacci number at compile-time. My main concern is: is it possible to get rid of the statickeyword (I had ...
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A multi key/value type "folded" map class template
I have recently come across a use case where I need to lump many maps into a single container. These maps can have different combinations of key/value types, but they all differ from one another.
For ...
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De-/Serialization of structs representing TCP messages
I wrote two template functions to serialize and deserialize structs representing messages to be sent and received via a TCP socket:
...
user51621
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330
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Generic way to access private/protected members
Motivation
I and the company is working on building C++ SDK automatically for several platforms, including Windows.
In summary, I have to test somehow if the private member of function pointers' type ...
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2k
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C++ Generic Callback class with removable listeners by unique id
I'm quite new to the STL.
Does this make sense? Is there a better way of removing the listeners instead of using shared_ptr while keeping the code short and simple? Is there something in the STL to ...
- 330
3
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1
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253
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Implementation of the basic matrix operations for embedded application in C++
I have been developing a control software in C++ and for implementation of the control algorithms I need basic matrix operations like addition, subtraction, multiplication and multiplication by scalar....
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1k
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C++ generic, multi-dimensional linear interpolation template
Use-case in a nutshell: Interpolate fixed-sized data (a lookup table) that provides output values for combinations of a (fixed) number of inputs. The appropriate scaling is done externally, each axis ...
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Binary IO inspired by struct pack
About
I'm writing a header-only template library for helping with binary IO. It is inspired by pack-d, which is in turn inspired by Python's struct module. I've only finished the output part and ...
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480
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Calculate the centroid of a collection of complex numbers
In working on another problem, one component I needed was to calculate the centroid of a collection of complex objects. The well-known way to calculate this is to simply average the real and ...
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struct,template arguments, C++ [closed]
I am writing color model logic in C++. I ask review in defining limits for the color model, by saying Limits I mean this.
Consider a struct which represents ...
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