rangeParser : Parser RawStr (Range Nat)
rangeParser =
    const (\first -> \last -> Range.new first last)
    |> keep digits
    |> skip (codeunit '-')
    |> keep digits

# Copied from roc-parser for debugging
digits : Parser RawStr Nat
digits =
    oneOrMore digit
    |> map \ds -> List.walk ds 0 (\sum, d -> sum * 10 + d)

Range a : { first : Num a, last : Num a } where a implements Bool.Eq

new : Num a, Num a -> Range a
new = \a, b -> { first: a, last: b }

── TYPE MISMATCH ──────────────────────────────────────────────────── main.roc ─

Something is off with the body of the rangeParser definition:

50│   rangeParser : Parser RawStr (Range Nat)
51│   rangeParser =
52│>      const (\first -> \last -> Range.new first last)
53│>      |> keep digits
54│>      |> skip (codeunit '-')
55│>      |> keep digits

This Core.keep call produces:

    Parser (List (Int Unsigned8)) (Range (Integer Natural))

But the type annotation on rangeParser says it should be:

    Parser (List (Int Unsigned8)) (Range Nat)

keep : Parser input (a -> b), Parser input a -> Parser input b

rangeBuilder : Nat -> Nat -> Range Nat
rangeBuilder = \first -> \last -> Range.new first last

── NOT END OF FILE ────────────────────────────────────────────────── main.roc ─

I expected to reach the end of the file, but got stuck here:

50│  rangeBuilder : Nat -> Nat -> Range Nat
                               ^

Range a : { first : a, last : a } where a implements Bool.Eq

new : Num a, Num a -> Range (Num a)
new = \a, b -> { first: a, last: b }

── TYPE MISMATCH ──────────────────────────────────────────────────── main.roc ─

Something is off with the body of the rangeParser definition:

52│   rangeParser : Parser RawStr (Range U32)
53│   rangeParser =
54│>      const (\first -> \last -> Range.new first last)
55│>      |> keep digits
56│>      |> skip (codeunit '-')
57│>      |> keep digits

This Core.keep call produces:

    Parser (List (Int Unsigned8)) (Range (Integer Natural))

But the type annotation on rangeParser says it should be:

    Parser (List (Int Unsigned8)) (Range U32)

rangeParser : Parser RawStr (Range U32)
rangeParser =
    const (\first -> \last -> Range.new (Num.intCast first) (Num.intCast last))
    |> keep digits
    |> skip (codeunit '-')
    |> keep digits

── TYPE MISMATCH ──────────────────────────────────────────────────── main.roc ─

Something is off with the body of the rangeParser definition:

52│   rangeParser : Parser RawStr (Range U32)
53│   rangeParser =
54│>      const (\first -> \last -> Range.new (Num.intCast first) (Num.intCast last))
55│>      |> keep digits
56│>      |> skip (codeunit '-')
57│>      |> keep digits

This Core.keep call produces:

    Parser (List (Int Unsigned8)) (Range (Integer b)) where b implements Eq

But the type annotation on rangeParser says it should be:

    Parser (List (Int Unsigned8)) (Range U32)

interface Range exposes [Range, new, min, max, intersection, isContained] imports []

Range := { first : U32, last : U32 } implements [Eq { isEq: rangeIsEq }]

rangeIsEq : Range, Range -> Bool
rangeIsEq = \@Range ra, @Range rb -> ra == rb

new : U32, U32 -> Range
new = \first, last -> @Range { first, last }

min : Range -> U32
min = \@Range { first, last } -> if first <= last then first else last

max : Range -> U32
max = \@Range { first, last } -> if first <= last then last else first

intersection : Range, Range -> [Disjoint, Intersecting (Range)]
intersection = \rangeA, rangeB ->
    if min rangeA > max rangeB || min rangeB > max rangeA then
        Disjoint
    else
        first = Num.max (min rangeA) (min rangeB)
        last = Num.min (max rangeA) (max rangeB)
        Intersecting (new first last)

expect intersection (new 0 5) (new 1 3) == Intersecting (new 1 3)

isContained : Range, Range -> Bool
isContained = \inner, outer ->
    intersection inner outer == Intersecting inner

expect new 1 3 == @Range {first: 1, last: 3}