X-Git-Url: https://gerrit.simantics.org/r/gitweb?p=simantics%2Fplatform.git;a=blobdiff_plain;f=bundles%2Forg.simantics.scl.runtime%2Fscl%2FPrelude.scl;h=6acbf924b1995ea0a082b29931d689bda66b53bb;hp=f06acb29fce55e74e98c111364ede07908947df9;hb=b3bbcce2479bba631466a15bef11581bafa676cc;hpb=8c1a41b09c7fbc5760f048ff9d3e5f9b468f8fbd diff --git a/bundles/org.simantics.scl.runtime/scl/Prelude.scl b/bundles/org.simantics.scl.runtime/scl/Prelude.scl index f06acb29f..6acbf924b 100644 --- a/bundles/org.simantics.scl.runtime/scl/Prelude.scl +++ b/bundles/org.simantics.scl.runtime/scl/Prelude.scl @@ -1081,12 +1081,12 @@ replicate n v = build (\empty cons -> /// FunctorM /// -class (Functor f) => FunctorM f where +class (FunctorE f) => FunctorM f where "`mapM f` is equivalent to `sequence . map f`." - mapM :: Monad m => (a -> m b) -> f a -> m (f b) + mapM :: Monad m => (a -> m b) -> f a -> m (f b) "Evaluate each action in the sequence from left to right, and collect the results." sequence :: Monad m => f (m a) -> m (f a) - mapM f l = sequence (fmap f l) + mapM f l = sequence (map f l) /// MonadE /// @@ -1162,6 +1162,14 @@ class IndexedSequence f where "`seq ! i` returns the `i`th element of the sequence `seq`. Indexing starts from zero." (!) :: f a -> Integer -> a +"Returns the first element of a sequence" +@inline +first l = l!0 + +"Returns the last element of a sequence" +@inline +last l = l!(length l-1) + instance IndexedSequence [] where (!) = getList @@ -1941,7 +1949,7 @@ importJava "org.simantics.scl.runtime.Lists" where Given a list of values and a function computing a key for each value, the function produces a function that finds a value effeciently for the given key. """ - indexBy :: (a -> b) -> [a] -> b -> Maybe a + indexBy :: (a -> b) -> [a] -> (b -> Maybe a) "Works like `index` but uses the given functions as hash codes and equality." indexWith :: (a -> Integer) -> (a -> a -> Boolean) -> [(a,b)] -> a -> Maybe b