71 lines
1.4 KiB
Text
71 lines
1.4 KiB
Text
-- main = head (Cons (sum (repeat 10 5)) Nil);
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main = case (bind (fmap (\s . s + 1) (Just 5)) (\s . pure (s + 10))) of {
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Just a => a ;
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Nothing => minusOne ;
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};
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---- MAYBE MONAD ----
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data Maybe () where {
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Just : Int -> Maybe ()
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Nothing : Maybe ()
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};
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fmap : (Int -> Int) -> Maybe () -> Maybe () ;
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fmap f m = case m of {
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Just a => pure (f a) ;
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Nothing => Nothing ;
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};
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pure : Int -> Maybe () ;
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pure x = Just x;
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-- scombinator not working yet :)
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bind : Maybe () -> (Int -> Maybe ()) -> Maybe () ;
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bind x f = case x of {
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Just x => f x ;
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Nothing => Nothing ;
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};
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-- represents minus one :)
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minusOne : Int ;
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minusOne = 9223372036854775807 + 9223372036854775807 + 1;
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---- LIST STUFF ----
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-- a simple list data type containing ints
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data List () where {
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Cons : Int -> List () -> List ()
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Nil : List ()
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};
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-- take the length of a list
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length : List () -> Int ;
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length x = case x of {
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Cons _ xs => 1 + length xs ;
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Nil => 0 ;
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};
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-- sum a list
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sum : List () -> Int ;
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sum x = case x of {
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Cons a xs => a + sum xs ;
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Nil => 0 ;
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};
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-- sum + length of a list
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sumlength: List () -> Int ;
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sumlength x = sum x + length x ;
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-- take the head of a list
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head : List () -> Int ;
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head x = case x of {
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Cons h _ => h ;
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};
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-- repeat an element n times
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repeat : Int -> Int -> List () ;
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repeat x n = case n of {
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0 => Nil ;
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n => Cons x (repeat x (n + minusOne)) ;
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};
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