Binary operations for AnyInt hierarchy

[LVMVRQUXL]

Description

Implement binary operations for the AnyInt hierarchy.

Checklist

• Implement the plus operations.
• Implement the minus operations.
• Implement the times operations.
• Implement the div operations.
• Implement the rem operations.
• Refactor code.
• Update the Unreleased section in changelog.

[LVMVRQUXL]

We should also introduce binary operations using the Int type as a parameter or receiver for a better integration with the standard library.

[LVMVRQUXL]

Here is the list of plus operations to implement:

/** Adds the [other] integer to this one. */
operator fun Int.plus(other: AnyInt): Int
operator fun AnyInt.plus(other: Int): Int
operator fun AnyInt.plus(other: AnyInt): Int

[LVMVRQUXL]

Here's the list of minus operations to implement:

/** Subtracts the [other] integer from this one. */
operator fun Int.minus(other: AnyInt): Int
operator fun AnyInt.minus(other: Int): Int
operator fun AnyInt.minus(other: AnyInt): Int

[LVMVRQUXL]

Here's the list of times operations to implement:

/** Multiplies this integer by the [other] one. */
operator fun Int.times(other: AnyInt): Int
operator fun AnyInt.times(other: Int): Int
operator fun AnyInt.times(other: AnyInt): Int

[LVMVRQUXL]

Here's the list of div operations to implement:

/**
 * Divides this integer by the [other] one, truncating the result to an integer
 * that is closer to [zero][ZeroInt].
 */
operator fun Int.div(other: NonZeroInt): Int
operator fun AnyInt.div(other: NonZeroInt): Int
operator fun PositiveInt.div(other: StrictlyPositiveInt): PositiveInt
operator fun PositiveInt.div(other: StrictlyNegativeInt): NegativeInt
operator fun NegativeInt.div(other: StrictlyPositiveInt): NegativeInt
operator fun NegativeInt.div(other: StrictlyNegativeInt): PositiveInt

[LVMVRQUXL]

Here's the list of rem operations to implement:

/**
 * Calculates the remainder of truncating division of this integer by the
 * [other] one.
 */
operator fun Int.rem(other: NonZeroInt): Int
operator fun AnyInt.rem(other: NonZeroInt): Int
operator fun PositiveInt.rem(other: NonZeroInt): PositiveInt
operator fun NegativeInt.rem(other: NonZeroInt): NegativeInt

[LVMVRQUXL]

Those changes will not be implemented according to our design principles.

[LVMVRQUXL]

Implementing those changes will simplify the usage of the AnyInt hierarchy.

val x: NonZeroInt = NonZeroInt.random()
val y: PositiveInt = PositiveInt.random()
var result: Int
// before
result = x.toInt() + 1
result = 1 + x.toInt()
result = x.toInt() + y.toInt()
// after
result = x + 1
result = 1 + x
result = x + y