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operator_dispatch::operator()

For different Sign and Rhs, operator_dispatch<Sign, Rhs>::operator() are defined differently. sop denotes the sign of operator of each specialization.

Left-Hand-Side Operand Specializations

When Rhs is false, operator() of the specializations are defined as follows:

Unary & Binary SOPs

When Sign is one of "+", "-", "*", "&",

// (1)
template <class T>
/* see below */ operator()(T&& self) const
    noexcept(noexcept(sop std::forward<T>(self)))
    requires(requires { sop std::forward<T>(self); });

// (2)
template <class T, class Arg>
/* see below */ operator()(T&& self, Arg&& arg) const
    noexcept(noexcept(std::forward<T>(self) sop std::forward<Arg>(arg)))
    requires(requires { std::forward<T>(self) sop std::forward<Arg>(arg); });

(1) Returns sop std::forward<T>(self).

(2) Returns std::forward<T>(self) sop std::forward<Arg>(arg).

Binary SOPs

When Sign is one of "/", "%", "==", "!=", ">", "<", ">=", "<=", "<=>", "&&", "||", "|", "^", "<<", ">>", "+=", "-=", "*=", "/=", "&=", "|=", "^=", "<<=", ">>=", ",", "->*",

// (3)
template <class T, class Arg>
/* see below */ operator()(T&& self, Arg&& arg) const
    noexcept(noexcept(std::forward<T>(self) sop std::forward<Arg>(arg)))
    requires(requires { std::forward<T>(self) sop std::forward<Arg>(arg); });

(3) Returns std::forward<T>(self) sop std::forward<Arg>(arg).

"++" and "--"

When Sign is either "++", "--",

// (4)
template <class T>
/* see below */ operator()(T&& self) const
    noexcept(noexcept(sop std::forward<T>(self)))
    requires(requires { sop std::forward<T>(self); });

// (5)
template <class T>
/* see below */ operator()(T&& self, int) const
    noexcept(noexcept(std::forward<T>(self) sop))
    requires(requires { std::forward<T>(self) sop; });

(4) Returns sop std::forward<T>(self).

(5) Returns std::forward<T>(self) sop.

"!" and "~"

When Sign is either "!", "~",

// (6)
template <class T>
/* see below */ operator()(T&& self) const
    noexcept(noexcept(sop std::forward<T>(self)))
    requires(requires { sop std::forward<T>(self); });

(6) Returns sop std::forward<T>(self).

"()"

When Sign is "()",

// (7)
template <class T, class... Args>
/* see below */ operator()(T&& self, Args&&... args) const
    noexcept(noexcept(std::forward<T>(self)(std::forward<Args>(args)...)))
    requires(requires { std::forward<T>(self)(std::forward<Args>(args)...); });

(7) Returns std::forward<T>(self)(std::forward<Args>(args)...).

"[]"

When Sign is "[]",

// (8) (until C++23)
template <class T, class... Args>
/* see below */ operator()(T&& self, Args&&... args) const
    noexcept(noexcept(std::forward<T>(self)[std::forward<Args>(args)...]))
    requires(requires { std::forward<T>(self)[std::forward<Args>(args)...]; });

// (9) (since C++23)
template <class T, class Arg>
/* see below */ operator()(T&& self, Arg&& arg) const
    noexcept(noexcept(std::forward<T>(self)[std::forward<Arg>(arg)]))
    requires(requires { std::forward<T>(self)[std::forward<Arg>(arg)]; });

(8) Returns std::forward<T>(self)[std::forward<Args>(args)...]. Requires the multidimensional subscript feature in C++23.

(9) Returns std::forward<T>(self)[std::forward<Arg>(arg)].

Right-Hand-Side Operand Specializations

When Sign is one of "+", "-", "*", "/", "%", "==", "!=", ">", "<", ">=", "<=", "<=>", "&&", "||", "&", "|", "^", "<<", ">>", "+=", "-=", "*=", "/=", "&=", "|=", "^=", "<<=", ">>=", ",", "->*", and Rhs is true,

// (10)
template <class T, class Arg>
/* see below */ operator()(T&& self, Arg&& arg) const
    noexcept(noexcept(std::forward<Arg>(arg) sop std::forward<T>(self)))
    requires(requires { std::forward<Arg>(arg) sop std::forward<T>(self); });

(10) Returns std::forward<Arg>(arg) sop std::forward<T>(self).