numeric.go

package nstd

// Signed is a constraint that permits any signed integer type.
// If future releases of Go add new predeclared signed integer types,
// this constraint will be modified to include them.
type Signed interface {
	~int | ~int8 | ~int16 | ~int32 | ~int64
}

// Unsigned is a constraint that permits any unsigned integer type.
// If future releases of Go add new predeclared unsigned integer types,
// this constraint will be modified to include them.
type Unsigned interface {
	~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr
}

// Integer is a constraint that permits any integer type.
// If future releases of Go add new predeclared integer types,
// this constraint will be modified to include them.
type Integer interface {
	Signed | Unsigned
}

// Float is a constraint that permits any floating-point type.
// If future releases of Go add new predeclared floating-point types,
// this constraint will be modified to include them.
type Float interface {
	~float32 | ~float64
}

// Complex is a constraint that permits any complex numeric type.
// If future releases of Go add new predeclared complex numeric types,
// this constraint will be modified to include them.
type Complex interface {
	~complex64 | ~complex128
}

type Real interface {
	Integer | Float
}

type Numeric interface {
	Integer | Float | Complex
}

// Sign returns the sign of a value of a [Signed] integer type.
// For a negative integer, it returns -1;
// for a positive integer, it returns 1;
// for 0, it returns 0.
func Sign[T Signed](x T) int {
	if x < 0 {
		return -1
	}
	if x > 0 {
		return 1
	}
	return 0
}