Last active
January 12, 2023 13:11
-
-
Save darvil82/fa81443a787abc13c71c196f94ef9b05 to your computer and use it in GitHub Desktop.
A shitty constexpr range thing in C++20
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
// Thanks craftablescience for some improvements! | |
#include <cstdio> | |
template<typename T = int> | |
class Range { | |
template<T start, T step> | |
class iterator { | |
T current = start; | |
public: | |
constexpr const T& operator*() const { return this->current; } | |
constexpr T& operator*() { return this->current; } | |
constexpr T* operator->() { return &this->current; } | |
constexpr const T* operator->() const { return &this->current; } | |
constexpr T& operator++() { | |
// yes += exists, doing this so the type does not require the overload. | |
return this->current = this->current + step; | |
} | |
template<T start_other> | |
constexpr bool operator!=(const iterator<start_other, step>& other) const { | |
return this->current != *other; | |
} | |
}; | |
public: | |
Range() = delete; | |
template<T start, T end_v, T step> requires (end_v >= start && step != 0) | |
struct between_step { | |
constexpr iterator<start, step> begin() { return {}; } | |
constexpr iterator<end_v, step> end() { return {}; } | |
}; | |
template<T start, T end> using between = between_step<start, end, 1>; | |
template<T end> using until = between<0, end>; | |
}; | |
consteval int test(){ | |
int value = 0; | |
for (int i : Range<>::between<5, 10>()) { | |
value += i; | |
} | |
return value; | |
} | |
int main() { | |
int result = test(); | |
printf("%d\n", result); | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment