AttrName: remove IsString instance

This change is motivated by the API wart that results from the
overloading of both "<>" and string literals that resulted in code like
this:

  a :: AttrName
  a = "blah" <> "things"

While this worked to create an AttrName with two segments, it is far too
easy to read this as two strings concatenated. The overloading hides
what is really going on with the segments of the attribute name. The way
to write the above example after this change is:

  a :: AttrName
  a = attrName "blah" <> attrName "things"

programs/AttrDemo.hs

@@ -23,28 +23,28 @@ import Brick.Widgets.Core
   , modifyDefAttr
   )
 import Brick.Util (on, fg)
-import Brick.AttrMap (attrMap, AttrMap)
+import Brick.AttrMap (attrMap, AttrMap, attrName)
 
 ui :: Widget n
 ui =
     vBox [ str "This text uses the global default attribute."
-         , withAttr "foundFull" $
+         , withAttr (attrName "foundFull") $
            str "Specifying an attribute name means we look it up in the attribute tree."
-         , (withAttr "foundFgOnly" $
+         , (withAttr (attrName "foundFgOnly") $
            str ("When we find a value, we merge it with its parent in the attribute")
            <=> str "name tree all the way to the root (the global default).")
-         , withAttr "missing" $
+         , withAttr (attrName "missing") $
            str "A missing attribute name just resumes the search at its parent."
-         , withAttr ("general" <> "specific") $
+         , withAttr (attrName "general" <> attrName "specific") $
            str "In this way we build complete attribute values by using an inheritance scheme."
-         , withAttr "foundFull" $
+         , withAttr (attrName "foundFull") $
            str "You can override everything ..."
-         , withAttr "foundFgOnly" $
+         , withAttr (attrName "foundFgOnly") $
            str "... or only what you want to change and inherit the rest."
          , str "Attribute names are assembled with the Monoid append operation to indicate"
          , str "hierarchy levels, e.g. \"window\" <> \"title\"."
          , str " "
-         , withAttr "linked" $
+         , withAttr (attrName "linked") $
            str "This text is hyperlinked in terminals that support hyperlinking."
          , str " "
          , hyperlink "http://www.google.com/" $
@@ -59,11 +59,12 @@ globalDefault = white `on` blue
 
 theMap :: AttrMap
 theMap = attrMap globalDefault
-    [ ("foundFull",               white `on` green)
-    , ("foundFgOnly",             fg red)
-    , ("general",                 yellow `on` black)
-    , ("general" <> "specific",   fg cyan)
-    , ("linked",                  fg yellow `withURL` "http://www.google.com/")
+    [ (attrName "foundFull",               white `on` green)
+    , (attrName "foundFgOnly",             fg red)
+    , (attrName "general",                 yellow `on` black)
+    , (attrName "general" <> attrName "specific",
+                                           fg cyan)
+    , (attrName "linked",                  fg yellow `withURL` "http://www.google.com/")
     ]
 
 app :: App () e ()

programs/BorderDemo.hs

@@ -68,7 +68,7 @@ mkBorderDemo (styleName, sty) =
     txt $ "  " <> styleName <> " style  "
 
 titleAttr :: A.AttrName
-titleAttr = "title"
+titleAttr = A.attrName "title"
 
 borderMappings :: [(A.AttrName, V.Attr)]
 borderMappings =

programs/CacheDemo.hs

@@ -1,5 +1,4 @@
 {-# LANGUAGE CPP #-}
-{-# LANGUAGE OverloadedStrings #-}
 module Main where
 
 import Control.Monad (void)
@@ -31,6 +30,7 @@ import Brick.Widgets.Center
   )
 import Brick.AttrMap
   ( AttrName
+  , attrName
   , attrMap
   )
 
@@ -66,7 +66,7 @@ appEvent (VtyEvent (V.EvKey V.KEsc [])) = M.halt
 appEvent _ = return ()
 
 emphAttr :: AttrName
-emphAttr = "emphasis"
+emphAttr = attrName "emphasis"
 
 app :: M.App Int e Name
 app =

programs/FileBrowserDemo.hs

@@ -12,7 +12,7 @@ import Control.Monad.State (get)
 import qualified Data.Text as Text
 import qualified Brick.Main as M
 import qualified Brick.Widgets.List as L
-import Brick.AttrMap (AttrName)
+import Brick.AttrMap (AttrName, attrName)
 import Brick.Types
   ( Widget
   , BrickEvent(..)
@@ -77,7 +77,7 @@ appEvent (VtyEvent ev) = do
 appEvent _ = return ()
 
 errorAttr :: AttrName
-errorAttr = "error"
+errorAttr = attrName "error"
 
 theMap :: A.AttrMap
 theMap = A.attrMap V.defAttr

programs/LayerDemo.hs

@@ -1,5 +1,4 @@
 {-# LANGUAGE CPP #-}
-{-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE TemplateHaskell #-}
 module Main where
 
@@ -31,6 +30,7 @@ import Brick.Util (fg)
 import Brick.AttrMap
   ( attrMap
   , AttrName
+  , attrName
   )
 
 data St =
@@ -96,7 +96,7 @@ appEvent (T.VtyEvent (V.EvKey V.KEsc [])) = M.halt
 appEvent _ = return ()
 
 arrowAttr :: AttrName
-arrowAttr = "attr"
+arrowAttr = attrName "attr"
 
 app :: M.App St e Name
 app =

programs/ListDemo.hs

@@ -1,4 +1,3 @@
-{-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE CPP #-}
 module Main where
 
@@ -84,7 +83,7 @@ initialState :: L.List () Char
 initialState = L.list () (Vec.fromList ['a','b','c']) 1
 
 customAttr :: A.AttrName
-customAttr = L.listSelectedAttr <> "custom"
+customAttr = L.listSelectedAttr <> A.attrName "custom"
 
 theMap :: A.AttrMap
 theMap = A.attrMap V.defAttr

programs/ListViDemo.hs

@@ -1,4 +1,3 @@
-{-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE CPP #-}
 module Main where
 
@@ -75,7 +74,7 @@ initialState :: L.List () Char
 initialState = L.list () (Vec.fromList ['a','b','c']) 1
 
 customAttr :: A.AttrName
-customAttr = L.listSelectedAttr <> "custom"
+customAttr = L.listSelectedAttr <> A.attrName "custom"
 
 theMap :: A.AttrMap
 theMap = A.attrMap V.defAttr

programs/MouseDemo.hs

@@ -1,5 +1,4 @@
 {-# LANGUAGE CPP #-}
-{-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE TemplateHaskell #-}
 module Main where
 
@@ -51,9 +50,9 @@ buttonLayer st =
       C.hCenterLayer (vLimit 3 $ hLimit 50 $ E.renderEditor (str . unlines) True (st^.edit))
     where
         buttons = mkButton <$> buttonData
-        buttonData = [ (Button1, "Button 1", "button1")
-                     , (Button2, "Button 2", "button2")
-                     , (Button3, "Button 3", "button3")
+        buttonData = [ (Button1, "Button 1", attrName "button1")
+                     , (Button2, "Button 2", attrName "button2")
+                     , (Button3, "Button 3", attrName "button3")
                      ]
         mkButton (name, label, attr) =
             let wasClicked = (fst <$> st^.lastReportedClick) == Just name
@@ -82,7 +81,7 @@ infoLayer st = T.Widget T.Fixed T.Fixed $ do
                 Just (name, T.Location l) ->
                     "Mouse down at " <> show name <> " @ " <> show l
     T.render $ translateBy (T.Location (0, h-1)) $ clickable Info $
-               withDefAttr "info" $
+               withDefAttr (attrName "info") $
                C.hCenter $ str msg
 
 appEvent :: T.BrickEvent Name e -> T.EventM Name St ()
@@ -104,10 +103,10 @@ appEvent ev =
 
 aMap :: AttrMap
 aMap = attrMap V.defAttr
-    [ ("info",      V.white `on` V.magenta)
-    , ("button1",   V.white `on` V.cyan)
-    , ("button2",   V.white `on` V.green)
-    , ("button3",   V.white `on` V.blue)
+    [ (attrName "info",      V.white `on` V.magenta)
+    , (attrName "button1",   V.white `on` V.cyan)
+    , (attrName "button2",   V.white `on` V.green)
+    , (attrName "button3",   V.white `on` V.blue)
     , (E.editFocusedAttr, V.black `on` V.yellow)
     ]
 

programs/ThemeDemo.hs

@@ -1,4 +1,3 @@
-{-# LANGUAGE OverloadedStrings #-}
 module Main where
 
 import Control.Monad (void)
@@ -32,7 +31,7 @@ import Brick.Widgets.Core
   , withDefAttr
   )
 import Brick.Util (on, fg)
-import Brick.AttrMap (AttrName)
+import Brick.AttrMap (AttrName, attrName)
 
 ui :: Widget n
 ui =
@@ -44,7 +43,7 @@ ui =
          ]
 
 keybindingAttr :: AttrName
-keybindingAttr = "keybinding"
+keybindingAttr = attrName "keybinding"
 
 theme1 :: Theme
 theme1 =

programs/VisibilityDemo.hs

@@ -1,4 +1,3 @@
-{-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE TemplateHaskell #-}
 {-# LANGUAGE CPP #-}
 module Main where
@@ -16,7 +15,7 @@ import qualified Brick.Types as T
 import qualified Brick.Main as M
 import qualified Brick.Widgets.Center as C
 import qualified Brick.Widgets.Border as B
-import Brick.AttrMap (AttrMap, AttrName, attrMap)
+import Brick.AttrMap (AttrMap, AttrName, attrMap, attrName)
 import Brick.Util (on)
 import Brick.Types
   ( Widget
@@ -56,7 +55,7 @@ vp3Size :: (Int, Int)
 vp3Size = (25, 25)
 
 selectedAttr :: AttrName
-selectedAttr = "selected"
+selectedAttr = attrName "selected"
 
 drawUi :: St -> [Widget Name]
 drawUi st = [ui]

src/Brick/AttrMap.hs

@@ -2,9 +2,6 @@
 {-# LANGUAGE DeriveGeneric #-}
 -- | This module provides types and functions for managing an attribute
 -- map which maps attribute names ('AttrName') to attributes ('Attr').
--- This module is designed to be used with the 'OverloadedStrings'
--- language extension to permit easy construction of 'AttrName' values
--- and you should also use 'mappend' ('<>') to combine names.
 --
 -- Attribute maps work by mapping hierarchical attribute names to
 -- attributes and inheriting parent names' attributes when child names
@@ -52,7 +49,6 @@ import Data.Bits ((.|.))
 import qualified Data.Map as M
 import Data.Maybe (catMaybes)
 import Data.List (inits)
-import Data.String (IsString(..))
 import GHC.Generics (Generic)
 
 import Graphics.Vty (Attr(..), MaybeDefault(..), Style)
@@ -65,9 +61,9 @@ import Graphics.Vty (Attr(..), MaybeDefault(..), Style)
 -- example:
 --
 -- @
--- "window" <> "border"
--- "window" <> "title"
--- "header" <> "clock" <> "seconds"
+-- attrName "window" <> attrName "border"
+-- attrName "window" <> attrName "title"
+-- attrName "header" <> attrName "clock" <> attrName "seconds"
 -- @
 data AttrName = AttrName [String]
               deriving (Show, Read, Eq, Ord, Generic, NFData)
@@ -79,9 +75,6 @@ instance Monoid AttrName where
     mempty = AttrName []
     mappend = (Sem.<>)
 
-instance IsString AttrName where
-    fromString = AttrName . (:[])
-
 -- | An attribute map which maps 'AttrName' values to 'Attr' values.
 data AttrMap = AttrMap Attr (M.Map AttrName Attr)
              | ForceAttr Attr

src/Brick/Forms.hs

@@ -642,15 +642,15 @@ toPassword s = txt $ T.replicate (T.length $ T.concat s) "*"
 
 -- | The namespace for the other form attributes.
 formAttr :: AttrName
-formAttr = "brickForm"
+formAttr = attrName "brickForm"
 
 -- | The attribute for form input fields with invalid values.
 invalidFormInputAttr :: AttrName
-invalidFormInputAttr = formAttr <> "invalidInput"
+invalidFormInputAttr = formAttr <> attrName "invalidInput"
 
 -- | The attribute for form input fields that have the focus.
 focusedFormInputAttr :: AttrName
-focusedFormInputAttr = formAttr <> "focusedInput"
+focusedFormInputAttr = formAttr <> attrName "focusedInput"
 
 -- | Returns whether all form fields in the form currently have valid
 -- values according to the fields' validation functions. This is useful

src/Brick/Widgets/Border.hs

@@ -39,7 +39,7 @@ import qualified Brick.BorderMap as BM
 
 -- | The top-level border attribute name.
 borderAttr :: AttrName
-borderAttr = "border"
+borderAttr = attrName "border"
 
 -- | Draw the specified border element using the active border style
 -- using 'borderAttr'.

src/Brick/Widgets/Core.hs

@@ -1544,17 +1544,17 @@ viewport vpname typ p =
 
 -- | The base attribute for scroll bars.
 scrollbarAttr :: AttrName
-scrollbarAttr = "scrollbar"
+scrollbarAttr = attrName "scrollbar"
 
 -- | The attribute for scroll bar troughs. This attribute is a
 -- specialization of @scrollbarAttr@.
 scrollbarTroughAttr :: AttrName
-scrollbarTroughAttr = scrollbarAttr <> "trough"
+scrollbarTroughAttr = scrollbarAttr <> attrName "trough"
 
 -- | The attribute for scroll bar handles. This attribute is a
 -- specialization of @scrollbarAttr@.
 scrollbarHandleAttr :: AttrName
-scrollbarHandleAttr = scrollbarAttr <> "handle"
+scrollbarHandleAttr = scrollbarAttr <> attrName "handle"
 
 maybeClick :: (Ord n)
            => n

src/Brick/Widgets/Dialog.hs

@@ -99,15 +99,15 @@ dialog title buttonData w =
 
 -- | The default attribute of the dialog
 dialogAttr :: AttrName
-dialogAttr = "dialog"
+dialogAttr = attrName "dialog"
 
 -- | The default attribute for all dialog buttons
 buttonAttr :: AttrName
-buttonAttr = "button"
+buttonAttr = attrName "button"
 
 -- | The attribute for the selected dialog button (extends 'dialogAttr')
 buttonSelectedAttr :: AttrName
-buttonSelectedAttr = buttonAttr <> "selected"
+buttonSelectedAttr = buttonAttr <> attrName "selected"
 
 -- | Render a dialog with the specified body widget. This renders the
 -- dialog as a layer, which makes this suitable as a top-level layer in

src/Brick/Widgets/Edit.hs

@@ -193,12 +193,12 @@ applyEdit f e = e & editContentsL %~ f
 
 -- | The attribute assigned to the editor when it does not have focus.
 editAttr :: AttrName
-editAttr = "edit"
+editAttr = attrName "edit"
 
 -- | The attribute assigned to the editor when it has focus. Extends
 -- 'editAttr'.
 editFocusedAttr :: AttrName
-editFocusedAttr = editAttr <> "focused"
+editFocusedAttr = editAttr <> attrName "focused"
 
 -- | Get the contents of the editor.
 getEditContents :: Monoid t => Editor t n -> [t]

src/Brick/Widgets/FileBrowser.hs

@@ -165,7 +165,7 @@ import qualified System.FilePath as FP
 import Text.Printf (printf)
 
 import Brick.Types
-import Brick.AttrMap (AttrName)
+import Brick.AttrMap (AttrName, attrName)
 import Brick.Widgets.Core
 import Brick.Widgets.List
 
@@ -837,49 +837,49 @@ attrForFileType UnixSocket = fileBrowserUnixSocketAttr
 
 -- | The base attribute for all file browser attributes.
 fileBrowserAttr :: AttrName
-fileBrowserAttr = "fileBrowser"
+fileBrowserAttr = attrName "fileBrowser"
 
 -- | The attribute used for the current directory displayed at the top
 -- of the browser.
 fileBrowserCurrentDirectoryAttr :: AttrName
-fileBrowserCurrentDirectoryAttr = fileBrowserAttr <> "currentDirectory"
+fileBrowserCurrentDirectoryAttr = fileBrowserAttr <> attrName "currentDirectory"
 
 -- | The attribute used for the entry information displayed at the
 -- bottom of the browser.
 fileBrowserSelectionInfoAttr :: AttrName
-fileBrowserSelectionInfoAttr = fileBrowserAttr <> "selectionInfo"
+fileBrowserSelectionInfoAttr = fileBrowserAttr <> attrName "selectionInfo"
 
 -- | The attribute used to render directory entries.
 fileBrowserDirectoryAttr :: AttrName
-fileBrowserDirectoryAttr = fileBrowserAttr <> "directory"
+fileBrowserDirectoryAttr = fileBrowserAttr <> attrName "directory"
 
 -- | The attribute used to render block device entries.
 fileBrowserBlockDeviceAttr :: AttrName
-fileBrowserBlockDeviceAttr = fileBrowserAttr <> "block"
+fileBrowserBlockDeviceAttr = fileBrowserAttr <> attrName "block"
 
 -- | The attribute used to render regular file entries.
 fileBrowserRegularFileAttr :: AttrName
-fileBrowserRegularFileAttr = fileBrowserAttr <> "regular"
+fileBrowserRegularFileAttr = fileBrowserAttr <> attrName "regular"
 
 -- | The attribute used to render character device entries.
 fileBrowserCharacterDeviceAttr :: AttrName
-fileBrowserCharacterDeviceAttr = fileBrowserAttr <> "char"
+fileBrowserCharacterDeviceAttr = fileBrowserAttr <> attrName "char"
 
 -- | The attribute used to render named pipe entries.
 fileBrowserNamedPipeAttr :: AttrName
-fileBrowserNamedPipeAttr = fileBrowserAttr <> "pipe"
+fileBrowserNamedPipeAttr = fileBrowserAttr <> attrName "pipe"
 
 -- | The attribute used to render symbolic link entries.
 fileBrowserSymbolicLinkAttr :: AttrName
-fileBrowserSymbolicLinkAttr = fileBrowserAttr <> "symlink"
+fileBrowserSymbolicLinkAttr = fileBrowserAttr <> attrName "symlink"
 
 -- | The attribute used to render Unix socket entries.
 fileBrowserUnixSocketAttr :: AttrName
-fileBrowserUnixSocketAttr = fileBrowserAttr <> "unixSocket"
+fileBrowserUnixSocketAttr = fileBrowserAttr <> attrName "unixSocket"
 
 -- | The attribute used for selected entries in the file browser.
 fileBrowserSelectedAttr :: AttrName
-fileBrowserSelectedAttr = fileBrowserAttr <> "selected"
+fileBrowserSelectedAttr = fileBrowserAttr <> attrName "selected"
 
 -- | A file type filter for use with 'setFileBrowserEntryFilter'. This
 -- filter permits entries whose file types are in the specified list.

src/Brick/Widgets/List.hs

@@ -250,17 +250,17 @@ listMoveToEnd l = listMoveTo (max 0 $ length (listElements l) - 1) l
 
 -- | The top-level attribute used for the entire list.
 listAttr :: AttrName
-listAttr = "list"
+listAttr = attrName "list"
 
 -- | The attribute used only for the currently-selected list item when
 -- the list does not have focus. Extends 'listAttr'.
 listSelectedAttr :: AttrName
-listSelectedAttr = listAttr <> "selected"
+listSelectedAttr = listAttr <> attrName "selected"
 
 -- | The attribute used only for the currently-selected list item when
 -- the list has focus. Extends 'listSelectedAttr'.
 listSelectedFocusedAttr :: AttrName
-listSelectedFocusedAttr = listSelectedAttr <> "focused"
+listSelectedFocusedAttr = listSelectedAttr <> attrName "focused"
 
 -- | Construct a list in terms of container 't' with element type 'e'.
 list :: (Foldable t)

src/Brick/Widgets/ProgressBar.hs

@@ -22,11 +22,11 @@ import Brick.Widgets.Core
 
 -- | The attribute of the completed portion of the progress bar.
 progressCompleteAttr :: AttrName
-progressCompleteAttr = "progressComplete"
+progressCompleteAttr = attrName "progressComplete"
 
 -- | The attribute of the incomplete portion of the progress bar.
 progressIncompleteAttr :: AttrName
-progressIncompleteAttr = "progressIncomplete"
+progressIncompleteAttr = attrName "progressIncomplete"
 
 -- | Draw a progress bar with the specified (optional) label and
 -- progress value. This fills available horizontal space and is one row