diff options
Diffstat (limited to 'BJC-Utils2/src/main/java/bjc/utils/funcdata/theory')
| -rw-r--r-- | BJC-Utils2/src/main/java/bjc/utils/funcdata/theory/Bifunctor.java | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/BJC-Utils2/src/main/java/bjc/utils/funcdata/theory/Bifunctor.java b/BJC-Utils2/src/main/java/bjc/utils/funcdata/theory/Bifunctor.java index 3bea135..e8c74fc 100644 --- a/BJC-Utils2/src/main/java/bjc/utils/funcdata/theory/Bifunctor.java +++ b/BJC-Utils2/src/main/java/bjc/utils/funcdata/theory/Bifunctor.java @@ -51,6 +51,47 @@ public interface Bifunctor<LeftType, RightType> { fmapRight(Function<OldRight, NewRight> func); /** + * Lift a pair of functions to a single function that maps over both + * parts of a pair + * + * @param <OldLeft> + * The old left type of the pair + * @param <OldRight> + * The old right type of the pair + * @param <NewLeft> + * The new left type of the pair + * @param <NewRight> + * The new right type of the pair + * @param leftFunc + * The function that maps over the left of the pair + * @param rightFunc + * The function that maps over the right of the pair + * @return A function that maps over both parts of the pair + */ + public default <OldLeft, OldRight, NewLeft, NewRight> + Function<Bifunctor<OldLeft, OldRight>, Bifunctor<NewLeft, NewRight>> + bimap(Function<OldLeft, NewLeft> leftFunc, + Function<OldRight, NewRight> rightFunc) { + Function<Bifunctor<OldLeft, OldRight>, Bifunctor<NewLeft, NewRight>> bimappedFunc = + (argPair) -> { + Function<Bifunctor<OldLeft, OldRight>, Bifunctor<NewLeft, OldRight>> leftMapper = + argPair.<OldLeft, OldRight, NewLeft> fmapLeft( + leftFunc); + + Bifunctor<NewLeft, OldRight> leftMappedFunctor = + leftMapper.apply(argPair); + Function<Bifunctor<NewLeft, OldRight>, Bifunctor<NewLeft, NewRight>> rightMapper = + leftMappedFunctor + .<NewLeft, OldRight, NewRight> fmapRight( + rightFunc); + + return rightMapper.apply(leftMappedFunctor); + }; + + return bimappedFunc; + } + + /** * Get the value contained on the left of this bifunctor * * @return The value on the left side of this bifunctor |