Int

Ints are infinite precision integer values.

Dark v1 Problems

Infinite precision

Problem: Dark v1 integers are 63-bit integers, they should be infinite precision.

Solution: make them infinite precision instead using a BigNum library

Status: Spec'ed

Problem: when we automatically coerce integers to/from JSON, many JSON implementations do not support integers larger than 53 bits (for example, the Twitter API has "id" and "id_str" fields because sometimes the "id" is bigger than 53 bits)

Solution:

Integer conversion into JSON should use a string if appropriate.
Integer conversion from JSON should always be typed, and so if there's an int it can be parsed from a stringified integer literal if appropriate

Status: Not spec'ed

Negative numbers

Problem: The fluid editor does not allow negative numbers.

Solution: a UX for negative numbers is described below, it was quite straightforward.

Status: Spec'ed

Arithmetic errors

Problem: some arithmetic operations can lead to errors:

division by 0
modulus by 0

Solution: these should return Result (Int, IntError). One problem here is how we can make the error rail less cumbersome so that this isn't really irritating to handle.

Status: spec'ed

Integers of other sizes

Problem: it can be useful to have integers of specific sizes, in order to better model specific values or enforce overflow

Solution: we should add int8, int16, int32, int64, uint8, uint16, uint32, uint64

Status: not spec'ed

v2 Spec

v2 Language definition

type Expr =
  | EInt { val = BigInt }
  | ...

type Pattern =
  | PInt { val : BigInt }
  | ...

type Dval =
  | DInt { val = BigInt }
  | ...

type DType =
  | TInt
  | ...

v2 Standard library: Int

type Error =
  | DivideByZero

// the same as V1
Int::absoluteValue(Int: a) -> Int
Int::add(Int: a, Int: b) -> Int
Int::clamp(Int: value, Int: limitA, Int: limitB) -> Int
Int::greaterThan(Int: a, Int: b) -> Bool
Int::greaterThanOrEqualTo(Int: a, Int: b) -> Bool
Int::lessThan(Int: a, Int: b) -> Bool
Int::lessThanOrEqualTo(Int: a, Int: b) -> Bool
Int::max(Int: a, Int: b) -> Int
Int::min(Int: a, Int: b) -> Int
Int::multiply(Int: a, Int: b) -> Int
Int::negate(Int: a) -> Int
Int::power(Int: base, Int: exponent) -> Int
Int::random_v1(Int: start, Int: end) -> Int
Int::remainder(Int: value, Int: divisor) -> Result
Int::sqrt(Int: a) -> Float
Int::subtract(Int: a, Int: b) -> Int
Int::toFloat(Int: a) -> Float

// different from v1
Int::divide(Int: a, Int: b) -> Result (Int, Error)
Int::mod(Int: a, Int: b) -> Result (Int, Error)
Int::sum(List Int: a) -> Int

v2 Editor changes

support negative integers
- allow entering - at the start of an integer to convert it to a negative number
- allow deleting - from the start of an integer to convert it back to a positive
- if typing - in a position that is not a binop, start a partial (already happens). Once a partial of -gets a number added, turn it into an integer
remove the conversion when a number gets too big - no longer needed for infinite precision ints

Json serialization changes

TODO: wait til we figure out how JSON serialization works in Dark v2

Darklang roadmap

Int