~alcinnz/haskell-stylist: Implement style tree flattening utility.

fcbba23e577176b22b66ce920fe933c38df2867f — Adrian Cochrane 4 years ago b93db8b

Implement style tree flattening utility.

This will be useful in Rhapsode for making sure voice synthesizers continue to
have full voice features information as the user jumps around the document.
And it will be useful for visual browsers in transitioning from layout to render.

patch browse

1 files changed, 8 insertions(+), 1 deletions(-)

M src/Data/CSS/StyleTree.hs

M src/Data/CSS/StyleTree.hs => src/Data/CSS/StyleTree.hs +8 -1

@@ 1,7 1,7 @@
 -- | Abstracts away tree traversals.
 -- Mostly used by callers including (soon) XML Conduit Stylist,
 -- but also used internally for generating counter text.
-module Data.CSS.StyleTree(StyleTree(..), treeOrder, treeOrder', Path, treeMap) where
+module Data.CSS.StyleTree(StyleTree(..), treeOrder, treeOrder', Path, treeMap, treeFlatten) where
 
 data StyleTree p = StyleTree {
     style :: p,


@@ 26,3 26,10 @@ treeOrder' _ _ _ [] _ = error "Invalid path during tree traversal!"
 
 treeMap :: (p -> p') -> StyleTree p -> StyleTree p'
 treeMap cb = treeOrder (\_ _ _ p -> ((), cb p)) ()
+
+treeFlatten :: StyleTree p -> [p]
+treeFlatten = treeFlatten' . children
+treeFlatten' :: [StyleTree p] -> [p]
+treeFlatten' (StyleTree p []:ps) = p : treeFlatten' ps
+treeFlatten' (StyleTree _ childs:sibs) = treeFlatten' childs ++ treeFlatten' sibs
+treeFlatten' [] = []