stellar_prune/build/packages/gleam_stdlib/src/gleam/int.gleam
2025-11-30 15:44:22 +01:00

828 lines
16 KiB
Gleam

//// Functions for working with integers.
////
//// ## Division by zero
////
//// In Erlang division by zero results in a crash, however Gleam does not have
//// partial functions and operators in core so instead division by zero returns
//// zero, a behaviour taken from Pony, Coq, and Lean.
////
//// This may seem unexpected at first, but it is no less mathematically valid
//// than crashing or returning a special value. Division by zero is undefined
//// in mathematics.
import gleam/float
import gleam/order.{type Order}
/// Returns the absolute value of the input.
///
/// ## Examples
///
/// ```gleam
/// absolute_value(-12)
/// // -> 12
/// ```
///
/// ```gleam
/// absolute_value(10)
/// // -> 10
/// ```
///
pub fn absolute_value(x: Int) -> Int {
case x >= 0 {
True -> x
False -> x * -1
}
}
/// Returns the results of the base being raised to the power of the
/// exponent, as a `Float`.
///
/// ## Examples
///
/// ```gleam
/// power(2, -1.0)
/// // -> Ok(0.5)
/// ```
///
/// ```gleam
/// power(2, 2.0)
/// // -> Ok(4.0)
/// ```
///
/// ```gleam
/// power(8, 1.5)
/// // -> Ok(22.627416997969522)
/// ```
///
/// ```gleam
/// 4 |> power(of: 2.0)
/// // -> Ok(16.0)
/// ```
///
/// ```gleam
/// power(-1, 0.5)
/// // -> Error(Nil)
/// ```
///
pub fn power(base: Int, of exponent: Float) -> Result(Float, Nil) {
base
|> to_float
|> float.power(exponent)
}
/// Returns the square root of the input as a `Float`.
///
/// ## Examples
///
/// ```gleam
/// square_root(4)
/// // -> Ok(2.0)
/// ```
///
/// ```gleam
/// square_root(-16)
/// // -> Error(Nil)
/// ```
///
pub fn square_root(x: Int) -> Result(Float, Nil) {
x
|> to_float
|> float.square_root()
}
/// Parses a given string as an int if possible.
///
/// ## Examples
///
/// ```gleam
/// parse("2")
/// // -> Ok(2)
/// ```
///
/// ```gleam
/// parse("ABC")
/// // -> Error(Nil)
/// ```
///
@external(erlang, "gleam_stdlib", "parse_int")
@external(javascript, "../gleam_stdlib.mjs", "parse_int")
pub fn parse(string: String) -> Result(Int, Nil)
/// Parses a given string as an int in a given base if possible.
/// Supports only bases 2 to 36, for values outside of which this function returns an `Error(Nil)`.
///
/// ## Examples
///
/// ```gleam
/// base_parse("10", 2)
/// // -> Ok(2)
/// ```
///
/// ```gleam
/// base_parse("30", 16)
/// // -> Ok(48)
/// ```
///
/// ```gleam
/// base_parse("1C", 36)
/// // -> Ok(48)
/// ```
///
/// ```gleam
/// base_parse("48", 1)
/// // -> Error(Nil)
/// ```
///
/// ```gleam
/// base_parse("48", 37)
/// // -> Error(Nil)
/// ```
///
pub fn base_parse(string: String, base: Int) -> Result(Int, Nil) {
case base >= 2 && base <= 36 {
True -> do_base_parse(string, base)
False -> Error(Nil)
}
}
@external(erlang, "gleam_stdlib", "int_from_base_string")
@external(javascript, "../gleam_stdlib.mjs", "int_from_base_string")
fn do_base_parse(a: String, b: Int) -> Result(Int, Nil)
/// Prints a given int to a string.
///
/// ## Examples
///
/// ```gleam
/// to_string(2)
/// // -> "2"
/// ```
///
@external(erlang, "erlang", "integer_to_binary")
@external(javascript, "../gleam_stdlib.mjs", "to_string")
pub fn to_string(x: Int) -> String
/// Prints a given int to a string using the base number provided.
/// Supports only bases 2 to 36, for values outside of which this function returns an `Error(Nil)`.
/// For common bases (2, 8, 16, 36), use the `to_baseN` functions.
///
/// ## Examples
///
/// ```gleam
/// to_base_string(2, 2)
/// // -> Ok("10")
/// ```
///
/// ```gleam
/// to_base_string(48, 16)
/// // -> Ok("30")
/// ```
///
/// ```gleam
/// to_base_string(48, 36)
/// // -> Ok("1C")
/// ```
///
/// ```gleam
/// to_base_string(48, 1)
/// // -> Error(Nil)
/// ```
///
/// ```gleam
/// to_base_string(48, 37)
/// // -> Error(Nil)
/// ```
///
pub fn to_base_string(x: Int, base: Int) -> Result(String, Nil) {
case base >= 2 && base <= 36 {
True -> Ok(do_to_base_string(x, base))
False -> Error(Nil)
}
}
@external(erlang, "erlang", "integer_to_binary")
@external(javascript, "../gleam_stdlib.mjs", "int_to_base_string")
fn do_to_base_string(a: Int, b: Int) -> String
/// Prints a given int to a string using base-2.
///
/// ## Examples
///
/// ```gleam
/// to_base2(2)
/// // -> "10"
/// ```
///
pub fn to_base2(x: Int) -> String {
do_to_base_string(x, 2)
}
/// Prints a given int to a string using base-8.
///
/// ## Examples
///
/// ```gleam
/// to_base8(15)
/// // -> "17"
/// ```
///
pub fn to_base8(x: Int) -> String {
do_to_base_string(x, 8)
}
/// Prints a given int to a string using base-16.
///
/// ## Examples
///
/// ```gleam
/// to_base16(48)
/// // -> "30"
/// ```
///
pub fn to_base16(x: Int) -> String {
do_to_base_string(x, 16)
}
/// Prints a given int to a string using base-36.
///
/// ## Examples
///
/// ```gleam
/// to_base36(48)
/// // -> "1C"
/// ```
///
pub fn to_base36(x: Int) -> String {
do_to_base_string(x, 36)
}
/// Takes an int and returns its value as a float.
///
/// ## Examples
///
/// ```gleam
/// to_float(5)
/// // -> 5.0
/// ```
///
/// ```gleam
/// to_float(0)
/// // -> 0.0
/// ```
///
/// ```gleam
/// to_float(-3)
/// // -> -3.0
/// ```
///
@external(erlang, "erlang", "float")
@external(javascript, "../gleam_stdlib.mjs", "identity")
pub fn to_float(x: Int) -> Float
/// Restricts an int between a lower and upper bound.
///
/// ## Examples
///
/// ```gleam
/// clamp(40, min: 50, max: 60)
/// // -> 50
/// ```
///
pub fn clamp(x: Int, min min_bound: Int, max max_bound: Int) -> Int {
x
|> min(max_bound)
|> max(min_bound)
}
/// Compares two ints, returning an order.
///
/// ## Examples
///
/// ```gleam
/// compare(2, 3)
/// // -> Lt
/// ```
///
/// ```gleam
/// compare(4, 3)
/// // -> Gt
/// ```
///
/// ```gleam
/// compare(3, 3)
/// // -> Eq
/// ```
///
pub fn compare(a: Int, with b: Int) -> Order {
case a == b {
True -> order.Eq
False ->
case a < b {
True -> order.Lt
False -> order.Gt
}
}
}
/// Compares two ints, returning the smaller of the two.
///
/// ## Examples
///
/// ```gleam
/// min(2, 3)
/// // -> 2
/// ```
///
pub fn min(a: Int, b: Int) -> Int {
case a < b {
True -> a
False -> b
}
}
/// Compares two ints, returning the larger of the two.
///
/// ## Examples
///
/// ```gleam
/// max(2, 3)
/// // -> 3
/// ```
///
pub fn max(a: Int, b: Int) -> Int {
case a > b {
True -> a
False -> b
}
}
/// Returns whether the value provided is even.
///
/// ## Examples
///
/// ```gleam
/// is_even(2)
/// // -> True
/// ```
///
/// ```gleam
/// is_even(3)
/// // -> False
/// ```
///
pub fn is_even(x: Int) -> Bool {
x % 2 == 0
}
/// Returns whether the value provided is odd.
///
/// ## Examples
///
/// ```gleam
/// is_odd(3)
/// // -> True
/// ```
///
/// ```gleam
/// is_odd(2)
/// // -> False
/// ```
///
pub fn is_odd(x: Int) -> Bool {
x % 2 != 0
}
/// Returns the negative of the value provided.
///
/// ## Examples
///
/// ```gleam
/// negate(1)
/// // -> -1
/// ```
///
pub fn negate(x: Int) -> Int {
-1 * x
}
/// Sums a list of ints.
///
/// ## Example
///
/// ```gleam
/// sum([1, 2, 3])
/// // -> 6
/// ```
///
pub fn sum(numbers: List(Int)) -> Int {
sum_loop(numbers, 0)
}
fn sum_loop(numbers: List(Int), initial: Int) -> Int {
case numbers {
[first, ..rest] -> sum_loop(rest, first + initial)
[] -> initial
}
}
/// Multiplies a list of ints and returns the product.
///
/// ## Example
///
/// ```gleam
/// product([2, 3, 4])
/// // -> 24
/// ```
///
pub fn product(numbers: List(Int)) -> Int {
product_loop(numbers, 1)
}
fn product_loop(numbers: List(Int), initial: Int) -> Int {
case numbers {
[first, ..rest] -> product_loop(rest, first * initial)
[] -> initial
}
}
@deprecated("Vendor this function into your codebase")
pub fn digits(x: Int, base: Int) -> Result(List(Int), Nil) {
case base < 2 {
True -> Error(Nil)
False -> Ok(digits_loop(x, base, []))
}
}
fn digits_loop(x: Int, base: Int, acc: List(Int)) -> List(Int) {
case absolute_value(x) < base {
True -> [x, ..acc]
False -> digits_loop(x / base, base, [x % base, ..acc])
}
}
@deprecated("Vendor this function into your codebase")
pub fn undigits(numbers: List(Int), base: Int) -> Result(Int, Nil) {
case base < 2 {
True -> Error(Nil)
False -> undigits_loop(numbers, base, 0)
}
}
fn undigits_loop(numbers: List(Int), base: Int, acc: Int) -> Result(Int, Nil) {
case numbers {
[] -> Ok(acc)
[digit, ..] if digit >= base -> Error(Nil)
[digit, ..rest] -> undigits_loop(rest, base, acc * base + digit)
}
}
/// Generates a random int between zero and the given maximum.
///
/// The lower number is inclusive, the upper number is exclusive.
///
/// ## Examples
///
/// ```gleam
/// random(10)
/// // -> 4
/// ```
///
/// ```gleam
/// random(1)
/// // -> 0
/// ```
///
/// ```gleam
/// random(-1)
/// // -> -1
/// ```
///
pub fn random(max: Int) -> Int {
{ float.random() *. to_float(max) }
|> float.floor
|> float.round
}
/// Performs a truncated integer division.
///
/// Returns division of the inputs as a `Result`: If the given divisor equals
/// `0`, this function returns an `Error`.
///
/// ## Examples
///
/// ```gleam
/// divide(0, 1)
/// // -> Ok(0)
/// ```
///
/// ```gleam
/// divide(1, 0)
/// // -> Error(Nil)
/// ```
///
/// ```gleam
/// divide(5, 2)
/// // -> Ok(2)
/// ```
///
/// ```gleam
/// divide(-99, 2)
/// // -> Ok(-49)
/// ```
///
pub fn divide(dividend: Int, by divisor: Int) -> Result(Int, Nil) {
case divisor {
0 -> Error(Nil)
divisor -> Ok(dividend / divisor)
}
}
/// Computes the remainder of an integer division of inputs as a `Result`.
///
/// Returns division of the inputs as a `Result`: If the given divisor equals
/// `0`, this function returns an `Error`.
///
/// Most the time you will want to use the `%` operator instead of this
/// function.
///
/// ## Examples
///
/// ```gleam
/// remainder(3, 2)
/// // -> Ok(1)
/// ```
///
/// ```gleam
/// remainder(1, 0)
/// // -> Error(Nil)
/// ```
///
/// ```gleam
/// remainder(10, -1)
/// // -> Ok(0)
/// ```
///
/// ```gleam
/// remainder(13, by: 3)
/// // -> Ok(1)
/// ```
///
/// ```gleam
/// remainder(-13, by: 3)
/// // -> Ok(-1)
/// ```
///
/// ```gleam
/// remainder(13, by: -3)
/// // -> Ok(1)
/// ```
///
/// ```gleam
/// remainder(-13, by: -3)
/// // -> Ok(-1)
/// ```
///
pub fn remainder(dividend: Int, by divisor: Int) -> Result(Int, Nil) {
case divisor {
0 -> Error(Nil)
divisor -> Ok(dividend % divisor)
}
}
/// Computes the modulo of an integer division of inputs as a `Result`.
///
/// Returns division of the inputs as a `Result`: If the given divisor equals
/// `0`, this function returns an `Error`.
///
/// Most the time you will want to use the `%` operator instead of this
/// function.
///
/// ## Examples
///
/// ```gleam
/// modulo(3, 2)
/// // -> Ok(1)
/// ```
///
/// ```gleam
/// modulo(1, 0)
/// // -> Error(Nil)
/// ```
///
/// ```gleam
/// modulo(10, -1)
/// // -> Ok(0)
/// ```
///
/// ```gleam
/// modulo(13, by: 3)
/// // -> Ok(1)
/// ```
///
/// ```gleam
/// modulo(-13, by: 3)
/// // -> Ok(2)
/// ```
///
pub fn modulo(dividend: Int, by divisor: Int) -> Result(Int, Nil) {
case divisor {
0 -> Error(Nil)
_ -> {
let remainder = dividend % divisor
case remainder * divisor < 0 {
True -> Ok(remainder + divisor)
False -> Ok(remainder)
}
}
}
}
/// Performs a *floored* integer division, which means that the result will
/// always be rounded towards negative infinity.
///
/// If you want to perform truncated integer division (rounding towards zero),
/// use `int.divide()` or the `/` operator instead.
///
/// Returns division of the inputs as a `Result`: If the given divisor equals
/// `0`, this function returns an `Error`.
///
/// ## Examples
///
/// ```gleam
/// floor_divide(1, 0)
/// // -> Error(Nil)
/// ```
///
/// ```gleam
/// floor_divide(5, 2)
/// // -> Ok(2)
/// ```
///
/// ```gleam
/// floor_divide(6, -4)
/// // -> Ok(-2)
/// ```
///
/// ```gleam
/// floor_divide(-99, 2)
/// // -> Ok(-50)
/// ```
///
pub fn floor_divide(dividend: Int, by divisor: Int) -> Result(Int, Nil) {
case divisor {
0 -> Error(Nil)
divisor ->
case dividend * divisor < 0 && dividend % divisor != 0 {
True -> Ok(dividend / divisor - 1)
False -> Ok(dividend / divisor)
}
}
}
/// Adds two integers together.
///
/// It's the function equivalent of the `+` operator.
/// This function is useful in higher order functions or pipes.
///
/// ## Examples
///
/// ```gleam
/// add(1, 2)
/// // -> 3
/// ```
///
/// ```gleam
/// import gleam/list
/// list.fold([1, 2, 3], 0, add)
/// // -> 6
/// ```
///
/// ```gleam
/// 3 |> add(2)
/// // -> 5
/// ```
///
pub fn add(a: Int, b: Int) -> Int {
a + b
}
/// Multiplies two integers together.
///
/// It's the function equivalent of the `*` operator.
/// This function is useful in higher order functions or pipes.
///
/// ## Examples
///
/// ```gleam
/// multiply(2, 4)
/// // -> 8
/// ```
///
/// ```gleam
/// import gleam/list
///
/// list.fold([2, 3, 4], 1, multiply)
/// // -> 24
/// ```
///
/// ```gleam
/// 3 |> multiply(2)
/// // -> 6
/// ```
///
pub fn multiply(a: Int, b: Int) -> Int {
a * b
}
/// Subtracts one int from another.
///
/// It's the function equivalent of the `-` operator.
/// This function is useful in higher order functions or pipes.
///
/// ## Examples
///
/// ```gleam
/// subtract(3, 1)
/// // -> 2
/// ```
///
/// ```gleam
/// import gleam/list
///
/// list.fold([1, 2, 3], 10, subtract)
/// // -> 4
/// ```
///
/// ```gleam
/// 3 |> subtract(2)
/// // -> 1
/// ```
///
/// ```gleam
/// 3 |> subtract(2, _)
/// // -> -1
/// ```
///
pub fn subtract(a: Int, b: Int) -> Int {
a - b
}
/// Calculates the bitwise AND of its arguments.
///
/// The exact behaviour of this function depends on the target platform.
/// On Erlang it is equivalent to bitwise operations on ints, on JavaScript it
/// is equivalent to bitwise operations on big-ints.
///
@external(erlang, "erlang", "band")
@external(javascript, "../gleam_stdlib.mjs", "bitwise_and")
pub fn bitwise_and(x: Int, y: Int) -> Int
/// Calculates the bitwise NOT of its argument.
///
/// The exact behaviour of this function depends on the target platform.
/// On Erlang it is equivalent to bitwise operations on ints, on JavaScript it
/// is equivalent to bitwise operations on big-ints.
///
@external(erlang, "erlang", "bnot")
@external(javascript, "../gleam_stdlib.mjs", "bitwise_not")
pub fn bitwise_not(x: Int) -> Int
/// Calculates the bitwise OR of its arguments.
///
/// The exact behaviour of this function depends on the target platform.
/// On Erlang it is equivalent to bitwise operations on ints, on JavaScript it
/// is equivalent to bitwise operations on big-ints.
///
@external(erlang, "erlang", "bor")
@external(javascript, "../gleam_stdlib.mjs", "bitwise_or")
pub fn bitwise_or(x: Int, y: Int) -> Int
/// Calculates the bitwise XOR of its arguments.
///
/// The exact behaviour of this function depends on the target platform.
/// On Erlang it is equivalent to bitwise operations on ints, on JavaScript it
/// is equivalent to bitwise operations on big-ints.
///
@external(erlang, "erlang", "bxor")
@external(javascript, "../gleam_stdlib.mjs", "bitwise_exclusive_or")
pub fn bitwise_exclusive_or(x: Int, y: Int) -> Int
/// Calculates the result of an arithmetic left bitshift.
///
/// The exact behaviour of this function depends on the target platform.
/// On Erlang it is equivalent to bitwise operations on ints, on JavaScript it
/// is equivalent to bitwise operations on big-ints.
///
@external(erlang, "erlang", "bsl")
@external(javascript, "../gleam_stdlib.mjs", "bitwise_shift_left")
pub fn bitwise_shift_left(x: Int, y: Int) -> Int
/// Calculates the result of an arithmetic right bitshift.
///
/// The exact behaviour of this function depends on the target platform.
/// On Erlang it is equivalent to bitwise operations on ints, on JavaScript it
/// is equivalent to bitwise operations on big-ints.
///
@external(erlang, "erlang", "bsr")
@external(javascript, "../gleam_stdlib.mjs", "bitwise_shift_right")
pub fn bitwise_shift_right(x: Int, y: Int) -> Int