bloglang/13/examples/letin.txt

48 lines
949 B
Plaintext

data Bool = { True, False }
data List a = { Nil, Cons a (List a) }
defn if c t e = {
case c of {
True -> { t }
False -> { e }
}
}
defn mergeUntil l r p = {
let {
defn mergeLeft nl nr = {
case nl of {
Nil -> { Nil }
Cons x xs -> { if (p x) (Cons x (mergeRight xs nr)) Nil }
}
}
defn mergeRight nl nr = {
case nr of {
Nil -> { Nil }
Cons x xs -> { if (p x) (Cons x (mergeLeft nl xs)) Nil }
}
}
} in {
mergeLeft l r
}
}
defn const x y = { x }
defn sum l = {
case l of {
Nil -> { 0 }
Cons x xs -> { x + sum xs }
}
}
defn main = {
let {
defn firstList = { Cons 1 (Cons 3 (Cons 5 Nil)) }
defn secondList = { Cons 2 (Cons 4 (Cons 6 Nil)) }
} in {
sum (mergeUntil firstList secondList (const True))
}
}