Very basic incomplete text editor experiment

programs/Main.hs

@@ -10,12 +10,13 @@ import Brick
 data St =
     St { msg :: String
        , focus :: FocusRing
+       , stEditor :: Editor
        }
 
 drawUI :: St -> Widget
 drawUI st =
-    let editor = txt (msg st) `withNamedCursor` (Name "edit", Location (length $ msg st, 0))
-    in vBox [ editor `withAttr` (cyan `on` blue)
+    let ew = edit (stEditor st)
+    in vBox [ ew `withAttr` (cyan `on` blue)
             , hBorder '-'
             , "stuff and things"
             ]
@@ -34,8 +35,10 @@ pickCursor st ls =
 
 initialState :: St
 initialState =
+    let eName = Name "edit"
     St { msg = ""
-       , focus = focusRing [Name "edit"]
+       , focus = focusRing [eName]
+       , stEditor = editor eName ""
        }
 
 main :: IO ()

src/Brick.hs

@@ -34,6 +34,28 @@ txt s = Widget { render = \_ _ a -> ( string a s
 instance IsString Widget where
     fromString = txt
 
+data Editor =
+    Editor { editStr :: String
+           , editCursorPos :: Int
+           , editorName :: Name
+           }
+
+editor :: Name -> String -> Editor
+editor name s = Editor s (length name) name
+
+edit :: Editor -> Widget
+edit e =
+    Widget { render = renderEditor
+           }
+    where
+        renderEditor loc sz@(width, _) attr =
+            let cursorPos = CursorLocation (Location (editCursorPos e, 0)) (Just $ editorName e)
+                w = hBox [ txt (editStr e)
+                         , txt (replicate (width - (length $ editStr e)) ' ')
+                         ]
+                (img, _) = render_ w loc sz attr
+            in (img, [cursorPos])
+
 hBorder :: Char -> Widget
 hBorder ch =
     Widget { render = \_ (width, _) attr -> ( charFill attr ch width 1