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hylogen 1.4
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| import Hylogen.Expr | |
| import Hylogen.WithHylide | |
| findWithDefault :: ToGLSLType a => | |
| (Expr a -> Booly) -> Expr a -> [Expr a] -> Expr a | |
| findWithDefault predicate = foldr (\x acc -> sel (predicate x) x acc) | |
| findWithDefault' :: (ToGLSLType a, ToGLSLType b) => | |
| (Expr a -> Booly) -> Expr b -> [(Expr a, Expr b)] -> Expr b | |
| findWithDefault' predicate x = foldr (\(a, b) acc -> sel (predicate a) b acc) x | |
| foo :: Vec1 | |
| foo = findWithDefault (`lt`10) 0 [1, 2, 11, 12, 14] | |
| -- ( (true && (1.0 < 10.0)) ? 1.0 : ( (true && (2.0 < 10.0)) ? 2.0 : ( (true && (11.0 < 10.0)) ? 11.0 : ( (true && (12.0 < 10.0)) ? 12.0 : ( (true && (14.0 < 10.0)) ? 14.0 : 0.0))))) | |
| bar :: Vec1 | |
| bar = findWithDefault' (`gt` time) 0 [(0, 0), (100, 1)] | |
| -- ( (true && (0.0 > time)) ? 0.0 : ( (true && (100.0 > time)) ? 1.0 : 0.0)) |
Here are the functions with explicit recursion:
Keep in mind sel is just the ternary operator:
-- haskell
sel b x y
-- C, javascript
b ? x : y
If x matches by the predicate, sel branches to x. Else, it recurses down the list.
findWithDefault predicate def (x:xs) = sel (predicate x) x (findWithDefault predicate def xs)
findWithDefault predicate def [] = defGiven (a, b) from the list, if a matches by the predicate, sel branches to b. Else, it recurses down the list.
findWithDefault' predicate def ((a, b):xs) = sel (predicate a) b (findWithDefault predicate def xs)
findWithDefault' predicate def [] = def
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