implmenet 'daW' motion (next: test it)

fcore/cursor.sml

@@ -790,6 +790,130 @@ struct
   fun aroundWordNext (lineGap, cursorIdx) =
     AroundWordNext.foldNext (lineGap, cursorIdx, ())
 
+  structure AroundWORDPrev =
+    MakeIfCharFolderPrev
+      (struct
+         type env = unit
+
+         fun loopNonSpace (strPos, shd, absIdx, stl) =
+           if strPos < 0 then
+             case stl of
+               shd :: stl =>
+                 loopNonSpace (String.size shd - 1, shd, absIdx, stl)
+             | [] => 0
+           else
+             let
+               val chr = String.sub (shd, strPos)
+             in
+               if Char.isSpace chr then absIdx + 1
+               else loopNonSpace (strPos - 1, shd, absIdx - 1, stl)
+             end
+
+         fun loopSpace (strPos, shd, absIdx, stl) =
+           if strPos < 0 then
+             case stl of
+               shd :: stl => loopSpace (String.size shd - 1, shd, absIdx, stl)
+             | [] => 0
+           else
+             let
+               val chr = String.sub (shd, strPos)
+             in
+               if chr = #"\n" then
+                 absIdx + 1
+               else if Char.isSpace chr then
+                 loopSpace (strPos - 1, shd, absIdx - 1, stl)
+               else
+                 absIdx + 1
+             end
+
+         fun fStart (strPos, shd, _, absIdx, stl, _, _) =
+           let
+             val chr = String.sub (shd, strPos)
+           in
+             if chr = #"\n" then
+               absIdx
+             else if Char.isSpace chr then
+               loopSpace (strPos - 1, shd, absIdx - 1, stl)
+             else
+               loopNonSpace (strPos - 1, shd, absIdx - 1, stl)
+           end
+       end)
+
+  fun aroundWORDPrev (lineGap, cursorIdx) =
+    AroundWORDPrev.foldPrev (lineGap, cursorIdx, ())
+
+  structure AroundWORDNext =
+    MakeIfCharFolderNext
+      (struct
+         type env = unit
+
+         fun stopAtFirstNonSpace (strPos, shd, absIdx, stl) =
+           if strPos = String.size shd then
+             case stl of
+               shd :: stl => stopAtFirstNonSpace (0, shd, absIdx, stl)
+             | [] => absIdx
+           else
+             let
+               val chr = String.sub (shd, strPos)
+             in
+               if chr = #"\n" then
+                 absIdx - 1
+               else if Char.isSpace chr then
+                 stopAtFirstNonSpace (strPos + 1, shd, absIdx + 1, stl)
+               else
+                 absIdx - 1
+             end
+
+         fun loopNonSpace (strPos, shd, absIdx, stl) =
+           if strPos = String.size shd then
+             case stl of
+               shd :: stl => loopNonSpace (0, shd, absIdx, stl)
+             | [] => absIdx
+           else
+             let
+               val chr = String.sub (shd, strPos)
+             in
+               if chr = #"\n" then
+                 absIdx - 1
+               else if Char.isSpace chr then
+                 stopAtFirstNonSpace (strPos + 1, shd, absIdx + 1, stl)
+               else
+                 loopNonSpace (strPos + 1, shd, absIdx + 1, stl)
+             end
+
+         fun loopSpace (strPos, shd, absIdx, stl) =
+           if strPos = String.size shd then
+             case stl of
+               shd :: stl => loopSpace (0, shd, absIdx, stl)
+             | [] => absIdx
+           else
+             let
+               val chr = String.sub (shd, strPos)
+             in
+               if chr = #"\n" then
+                 absIdx - 1
+               else if Char.isSpace chr then
+                 loopSpace (strPos + 1, shd, absIdx + 1, stl)
+               else
+                 loopNonSpace (strPos + 1, shd, absIdx + 1, stl)
+             end
+
+         fun fStart (strPos, shd, _, absIdx, stl, _, _) =
+           let
+             val chr = String.sub (shd, strPos)
+           in
+             if chr = #"\n" then
+               absIdx
+             else if Char.isSpace chr then
+               loopSpace (strPos + 1, shd, absIdx + 1, stl)
+             else
+               loopNonSpace (strPos + 1, shd, absIdx + 1, stl)
+           end
+       end)
+
+  fun aroundWORDNext (lineGap, cursorIdx) =
+    AroundWORDNext.foldNext (lineGap, cursorIdx, ())
+
   fun isCursorAtStartOfLine (lineGap: LineGap.t, cursorIdx) =
     let
       val {rightStrings, idx = bufferIdx, ...} = lineGap