94 lines
2.1 KiB
C++
94 lines
2.1 KiB
C++
#include <concepts>
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#include <string>
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namespace clanguml {
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namespace t00056 {
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template <typename T, typename L>
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concept greater_than_simple = sizeof(T) > sizeof(L);
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template <typename T, typename P>
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concept greater_than_with_requires =
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requires(T l, P r) { sizeof(l) > sizeof(r); };
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// Constraint expression
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template <typename T>
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concept max_four_bytes = sizeof(T) <= 4;
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// Simple requirement
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template <typename T>
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concept iterable = requires(T container) {
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container.begin();
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container.end();
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};
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// Type requirement
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template <typename T>
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concept has_value_type = requires { typename T::value_type; };
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template <typename T>
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concept convertible_to_string =
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max_four_bytes<T> && requires(T s) {
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std::string{s};
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{
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std::to_string(s)
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} noexcept;
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{
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std::to_string(s)
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} -> std::same_as<std::string>;
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};
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// Compound requirement
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// ...
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// Combined concept
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template <typename T>
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concept iterable_with_value_type = iterable<T> && has_value_type<T>;
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template <typename T>
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concept iterable_or_small_value_type =
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iterable_with_value_type<T> || max_four_bytes<T>;
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// Simple type constraint
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template <max_four_bytes T> struct A {
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T a;
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};
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// Requires constant expression
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template <typename T>
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requires iterable_or_small_value_type<T>
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struct B {
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T b;
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};
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// Anonymous concept requirement (TODO)
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template <convertible_to_string T>
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requires requires(T t) {
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--t;
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t--;
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}
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struct C {
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T c;
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};
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template <iterable T1, typename T2, iterable T3, typename T4, typename T5>
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requires max_four_bytes<T2> && max_four_bytes<T5>
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struct D { };
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template <typename T1, typename T2, typename T3>
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requires greater_than_with_requires<T1, T3>
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struct E {
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T1 e1;
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T2 e2;
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T3 e3;
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};
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template <typename T1, typename T2, typename T3>
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requires greater_than_simple<T1, T3>
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struct F {
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T1 f1;
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T2 f2;
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T3 f3;
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};
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}
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} |