Re: [xmonad] XMonad.Config.Prime, a monadic config syntax

Just looking at the Haddocks, I like it very much! Can you say a bit more about exactly why TH is required? I get that fclabels depends on it, but why do you have to turn on the TemplateHaskell flag in your xmonad config? (I haven't actually looked at the code.) I'm a bit wary of adding a TH dep, but for a different reason than what others have said. TH versions are tied tightly to the changing Haskell syntax supported by different releases of GHC, so in theory a TH dep makes it harder to have a package that works under a wide range of GHC (and hence TH) versions. I don't know how much of a problem this is in practice. -Brent On Sun, Sep 23, 2012 at 11:36:58PM -0700, Devin Mullins wrote:

Hello, folks. Loooong time no see. I had some free time and spare energy this weekend, and this one had always been curiousing me. A couple things:

1. I `darcs rec`d with --no-test, since Minimize was complaining about a shadowed identifier.

2. This adds new build deps on fclabels and template-haskell. I know y'all are generally fairly conservative on new deps. What do you think?

3. Here's a live copy of the haddock doc: http://twifkak.com/xmonad-junk/XMonad-Config-Prime.html

Sun Sep 23 22:57:31 PDT 2012 Devin Mullins * XMonad.Config.Prime, a monadic config syntax This is an attempt at a cleaner and more modular config syntax, a follow up to http://thread.gmane.org/gmane.comp.lang.haskell.xmonad/5398. (Hello, everybody! How have the last four years been?)

FAQ:

Why fclabels instead of data-lens? Of the two, it was the one that successfully compiled on my ancient Ubuntu Lucid machine when I ran `cabal install`.

...

data L = forall l. L l g f (L l) = L (f l) so I can't really make a generic Layout transformer. I spent a few minutes

Ick, template-haskell? Really? Yeah, I know. Unfortunately, it seems that GHC won't let me write: heading down the path of parameterized monads and NoImplicitPrelude, but the type-system mind games and the juggling between (Prelude.>>) for IO and (Control.Monad.Parameterized.>>) for state were melting my brain.

Sun Sep 23 23:20:20 PDT 2012 Devin Mullins * minor tweaks to X.C.Prime

[XMonad.Config.Prime, a monadic config syntax Devin Mullins **20120924055731 Ignore-this: e5d7c999a892d2eb8447de692edec708 This is an attempt at a cleaner and more modular config syntax, a follow up to http://thread.gmane.org/gmane.comp.lang.haskell.xmonad/5398. (Hello, everybody! How have the last four years been?)

FAQ:

Why fclabels instead of data-lens? Of the two, it was the one that successfully compiled on my ancient Ubuntu Lucid machine when I ran `cabal install`.

...

data L = forall l. L l g f (L l) = L (f l) so I can't really make a generic Layout transformer. I spent a few minutes

Ick, template-haskell? Really? Yeah, I know. Unfortunately, it seems that GHC won't let me write: heading down the path of parameterized monads and NoImplicitPrelude, but the type-system mind games and the juggling between (Prelude.>>) for IO and (Control.Monad.Parameterized.>>) for state were melting my brain. ] { addfile ./XMonad/Config/Prime.hs hunk ./XMonad/Config/Prime.hs 1 +{-# LANGUAGE ExistentialQuantification, FlexibleContexts, FlexibleInstances, FunctionalDependencies, MultiParamTypeClasses, TemplateHaskell, TypeOperators, TypeSynonymInstances #-} + +----------------------------------------------------------------------------- +-- | +-- Module : XMonad.Config.Prime +-- Copyright : Devin Mullins +-- License : BSD-style (see LICENSE) +-- +-- Maintainer : Devin Mullins +-- Stability : unstable +-- Portability : unportable +-- +-- This is a draft of a brand new config syntax for xmonad. It aims to be: +-- +-- * easier to copy/paste snippets from the docs +-- +-- * easier to get the gist for what's going on, for you imperative programmers +-- +-- It's brand new, so it's pretty much guaranteed to break or change syntax. +-- But what's the worst that could happen? Xmonad crashes and logs you out? +-- Give it a try. Start at the /Start here/ section. +-- +----------------------------------------------------------------------------- + +-- monads, lenses, dsls, oh my! +module XMonad.Config.Prime ( +-- * Start here +-- $start_here +xmonad, +nothing, + +-- * Attributes you can set +-- $settables +normalBorderColor, +focusedBorderColor, +terminal, +modMask, +borderWidth, +focusFollowsMouse, +(=:), +-- | This lets you set an attribute. +(=.), +-- | This lets you apply a function to an attribute (i.e. read, modify, write). + +-- * Attributes you can add to +-- $summables +keys, +mouseBindings, +manageHook, +handleEventHook, +workspaces, +logHook, +startupHook, +(=+), + +-- * Modifying the layoutHook +-- $layout +addLayout, +modifyLayout, +resetLayout, +layoutHook, + +-- * Update entire XConfig +-- $update +modify, +update, + +-- * The rest of XMonad +-- | Everything you know and love from the core "XMonad" is available for use in +-- your config file, too. +module XMonad, + +-- * Example config +-- $example + +-- * Devel stuff +-- | People wanting to implement extensions to the config system, or just play +-- around, might want access to these. Regular people shouldn't need them. +Prime, +getConfig, +Summable, +) where + +import Control.Monad.State.Lazy (StateT, execStateT) +import qualified Data.Map as M +import Data.Label (lens, (:->)) +import Data.Label.PureM ((=:), (=.), gets) +import Data.Monoid (All, Monoid, mappend) +import Language.Haskell.TH (Exp, Q) + +import XMonad hiding (xmonad, XConfig(..), gets) +import XMonad (XConfig(XConfig)) +import qualified XMonad as X (xmonad, XConfig(..)) + +import XMonad.Util.EZConfig (additionalKeysP, additionalMouseBindings) + +-- $start_here +-- To start with, have a @~\/.xmonad\/xmonad.hs@ that looks like this: +-- +-- > {-# LANGUAGE TemplateHaskell #-} +-- > +-- > import XMonad.Config.Prime +-- > +-- > -- Imports go here. +-- > +-- > main = xmonad $ do +-- > nothing +-- > -- Configs go here. +-- +-- This will give you a default xmonad install, with room to grow. The lines +-- starting with double dashes are comments. You may delete them. Note that +-- Haskell is a bit precise about indentation. Make sure all the statements in +-- your do-block start at the same column, and make sure that any multi-line +-- statements are indented further on the subsequent lines. (For an example, +-- see the 'keys' statement in the /Example config/ section, below.) + +-- +-- The Prime Monad +-- + +-- | As you can see, this is a 'StateT' 'IO'. You can weave IO into your config +-- modification. Note that it's an 'XConfig' 'Layout' -- you'll have to unwrap +-- the existential to do anything useful to the layout. +type Prime = StateT (XConfig Layout) IO () + +wrapConf :: (LayoutClass l Window, Read (l Window)) => XConfig l -> XConfig Layout +wrapConf conf = conf { X.layoutHook = Layout $ X.layoutHook conf } + +defaultConf :: XConfig Layout +defaultConf = wrapConf defaultConfig + +-- | This is the xmonad main function. It passes defaultConfig to your +-- do-block, takes the modified config out of your do-block, and runs xmonad. +-- +-- The do-block is a 'Prime' monad. Advanced readers can skip right to that +-- definition. +xmonad :: Prime -> IO () +xmonad prime = do + conf@XConfig { X.layoutHook = Layout l } <- getConfig prime + X.xmonad conf { X.layoutHook = l } + +-- | This doesn't modify the config in any way. It's just here for your initial +-- config because Haskell doesn't allow empty do-blocks. Feel free to delete it +-- once you've added other stuff. +nothing :: Prime +nothing = return () + +-- $settables +-- These are a bunch of attributes that you can set. Syntax looks like this: +-- +-- > terminal =: "urxvt" +-- +-- Strings are double quoted, Dimensions are unquoted integers, booleans are +-- 'True' or 'False' (case-sensitive), and 'modMask' is usually 'mod1Mask' or +-- 'mod4Mask'. + +-- | Non-focused windows border color. Default: @\"#dddddd\"@ +normalBorderColor :: XConfig Layout :-> String +normalBorderColor = lens X.normalBorderColor (\x c -> c { X.normalBorderColor = x }) + +-- | Focused windows border color. Default: @\"#ff0000\"@ +focusedBorderColor :: XConfig Layout :-> String +focusedBorderColor = lens X.focusedBorderColor (\x c -> c { X.focusedBorderColor = x }) + +-- | The preferred terminal application. Default: @\"xterm\"@ +terminal :: XConfig Layout :-> String +terminal = lens X.terminal (\x c -> c { X.terminal = x }) + +-- | The mod modifier, as used by key bindings. Default: @mod1Mask@ (which is +-- probably alt on your computer). +modMask :: XConfig Layout :-> KeyMask +modMask = lens X.modMask (\x c -> c { X.modMask = x }) + +-- | The border width (in pixels). Default: @1@ +borderWidth :: XConfig Layout :-> Dimension +borderWidth = lens X.borderWidth (\x c -> c { X.borderWidth = x }) + +-- | Whether window focus follows the mouse cursor on move, or requires a mouse +-- click. (Mouse? What's that?) Default: @True@ +focusFollowsMouse :: XConfig Layout :-> Bool +focusFollowsMouse = lens X.focusFollowsMouse (\x c -> c { X.focusFollowsMouse = x }) + +-- $summables +-- In addition to being able to set these attributes, they have a special +-- syntax for being able to add to them. The operator is @=+@ (the plus comes +-- /after/ the equals), but each attribute has a different syntax for what +-- comes after the operator. + +-- | The action to run when a new window is opened. Default: +-- +-- > manageHook =: composeAll [className =? "MPlayer" --> doFloat, className =? "Gimp" --> doFloat] +-- +-- To add more rules to this list, you can say, for instance: +-- +-- > manageHook =+ (className =? "Emacs" --> doF . kill =<< ask) +-- > manageHook =+ (className =? "Vim" --> doF . shiftMaster =<< ask) +-- +-- Note that operator precedence mandates the parentheses here. +manageHook :: XConfig Layout :-> ManageHook +manageHook = lens X.manageHook (\x c -> c { X.manageHook = x }) + +-- | Custom X event handler. Return @All True@ if the default handler should +-- also be run afterwards. Default does nothing. To add an event handler: +-- +-- > import XMonad.Hooks.ServerMode +-- > ... +-- > manageHook =+ serverModeEventHook +handleEventHook :: XConfig Layout :-> (Event -> X All) +handleEventHook = lens X.handleEventHook (\x c -> c { X.handleEventHook = x }) + +-- | List of workspaces' names. Default: @map show [1 .. 9 :: Int]@. Adding +-- appends to the end: +-- +-- > workspaces =+ ["0"] +-- +-- This is useless unless you also create keybindings for this. +workspaces :: XConfig Layout :-> [String] +workspaces = lens X.workspaces (\x c -> c { X.workspaces = x }) + +-- TODO: Rework the workspaces thing to pair names with keybindings. + +-- | Map from key presses to actions. Default: see `man xmonad`. @keys +=@ +-- takes a list of keybindings specified emacs-style, as documented in +-- 'XMonad.Util.EZConfig.mkKeyMap'. For example, to add a help button to +-- XMonad: +-- +-- > keys += [("<F1>", spawn "echo RTFS | dzen2 -p 2")] +keys :: XConfig Layout :-> (XConfig Layout -> M.Map (ButtonMask,KeySym) (X ())) +keys = lens X.keys (\x c -> c { X.keys = x }) + +-- | Map from button presses to actions. Default: see `man xmonad`. To make +-- mod-<scrollwheel> switch workspaces: +-- +-- > import XMonad.Actions.CycleWS (nextWS, prevWS) +-- > ... +-- > mouseBindings =+ [((mod4Mask, button4), prevWS), +-- > ((mod4Mask, button5), nextWS)] +-- +-- Note that you need to specify the numbered mod-mask e.g. 'mod4Mask' instead +-- of just 'modMask'. +mouseBindings :: XConfig Layout :-> (XConfig Layout -> M.Map (ButtonMask, Button) (Window -> X ())) +mouseBindings = lens X.mouseBindings (\x c -> c { X.mouseBindings = x }) + +-- TODO: Fix the need to specify mod4Mask instead of modMask? Does anybody care? + +-- | The action to perform when the windows set is changed. This happens +-- whenever focus change, a window is moved, etc. @logHook =+@ takes an @X ()@ +-- and appends it via '(>>)'. For instance: +-- +-- > import XMonad.Hooks.ICCCMFocus +-- > ... +-- > logHook =+ takeTopFocus +logHook :: XConfig Layout :-> X () +logHook = lens X.logHook (\x c -> c { X.logHook = x }) + +-- | The action to perform on startup. @startupHook =+@ takes an @X ()@ and +-- appends it via '(>>)'. For instance: +-- +-- > import XMonad.Hooks.SetWMName +-- > ... +-- > startupHook =+ setWMName "LG3D" +startupHook :: XConfig Layout :-> X () +startupHook = lens X.startupHook (\x c -> c { X.startupHook = x }) + +-- The Summable class and instance definitions are further down. + +-- $layout +-- Layouts are special. Theoretically, you can use the @=:@ and @=.@ syntax to +-- set them, but I'm not sure you want to. There's some cruft involved. The +-- following macros make it a little nicer: + +-- (Stupid existential quantification. Make me write ridiculous code like this.) + +-- | Add a layout to the list of layouts choosable with mod-space. For instance: +-- +-- > import XMonad.Layout.Tabbed +-- > ... +-- > $(addLayout [| simpleTabbed |]) +addLayout :: Q Exp -> Q Exp +addLayout qexp = [| layoutHook =. (\(Layout l) -> Layout (l ||| $qexp)) |] + +-- | Modify your 'layoutHook' with some wrapper function. You probably want to call +-- this after you're done calling 'addLayout'. Example: +-- +-- > import XMonad.Layout.NoBorders +-- > ... +-- > $(modifyLayout [| smartBorders |]) +modifyLayout :: Q Exp -> Q Exp +modifyLayout qexp = [| layoutHook =. (\(Layout l) -> Layout ($qexp l)) |] + +-- | Reset the layoutHook from scratch. For instance, to get rid of the wide +-- layout: +-- +-- > $(resetLayout [| Tall 1 (3/100) (1/2) ||| Full |]) +resetLayout :: Q Exp -> Q Exp +resetLayout qexp = [| layoutHook =: Layout $qexp |] + +layoutHook :: XConfig Layout :-> Layout Window +layoutHook = lens X.layoutHook (\x c -> c { X.layoutHook = x }) + +-- $update +-- Finally, there are a few contrib modules that bundle multiple attribute +-- updates up into functions that update the entire configuration. You can use +-- 'modify' or 'update' to wire them into this config syntax. Which one +-- depends on whether or not the IO monad is involved. +-- +-- For instance, 'XMonad.Hooks.UrgencyHook.withUrgencyHook' returns an @XConfig +-- l@, so we need to use 'modify': +-- +-- > import XMonad.Hooks.UrgencyHook +-- > ... +-- > modify $ withUrgencyHook dzenUrgencyHook +-- +-- On the other hand, 'XMonad.Hooks.DynamicLog.xmobar' returns an @IO (XConfig +-- l)@, so we need to use 'update': +-- +-- > import XMonad.Actions.WindowNavigation +-- > ... +-- > update $ xmobar +-- +-- (Haskellers will note that the dollar sign is not actually necessary in this +-- case, but it doesn't hurt. The dollar sign is like an auto-closing +-- parenthesis.) + +update :: (XConfig Layout -> IO (XConfig Layout)) -> Prime +update f = get >>= io . f >>= put + +-- | Returns the modified config file resulting from passing 'defaultConfig' to +-- the 'Prime'. Implementing a 'Show' instance for 'XConfig' 'Layout' is left +-- as an exercise for the reader. +getConfig :: Prime -> IO (XConfig Layout) +getConfig m = execStateT m defaultConf + +-- +-- Summables +-- + +-- | The class for summable things. If you want to invent new summable +-- attributes, here's what you use. +class Summable a b | a -> b where + -- | How you add to a summable. + (=+) :: a -> b -> Prime + infix 0 =+ + +instance Summable (XConfig Layout :-> (XConfig Layout -> M.Map (ButtonMask,KeySym) (X ()))) + [(String, X ())] where + _ =+ newKeys = modify (`additionalKeysP` newKeys) + +instance Summable (XConfig Layout :-> (XConfig Layout -> M.Map (ButtonMask, Button) (Window -> X ()))) + [((ButtonMask, Button), Window -> X ())] where + _ =+ newMouseBindings = modify (`additionalMouseBindings` newMouseBindings) + +instance Summable (XConfig Layout :-> ManageHook) ManageHook where + l =+ new = l =. (<+> new) + +instance Summable (XConfig Layout :-> (Event -> X All)) (Event -> X All) where + l =+ new = do + old <- gets l + l =: \evt -> old evt `mappend` new evt + +instance Summable (XConfig Layout :-> [String]) [String] where + l =+ new = l =. (++ new) + +instance Summable (XConfig Layout :-> X ()) (X ()) where + l =+ new = l =. (>> new) + +-- $example +-- As an example, I've included below a subset of my current config. Note that +-- my import statements specify individual identifiers in parentheticals. +-- That's optional. The default is to import the entire module. I just find it +-- helpful to remind me where things came from. +-- +-- > {-# LANGUAGE TemplateHaskell #-} +-- > +-- > import XMonad.Config.Prime +-- > +-- > import XMonad.Actions.CycleWS (nextWS, prevWS) +-- > import XMonad.Actions.WindowNavigation (withWindowNavigation) +-- > import XMonad.Hooks.ManageHelpers (doFullFloat, isFullscreen) +-- > import XMonad.Layout.NoBorders (smartBorders) +-- > import XMonad.Prompt (defaultXPConfig, XPConfig(position), XPPosition(Top)) +-- > import XMonad.Prompt.Shell (shellPrompt) +-- > +-- > main = xmonad $ do +-- > modMask =: mod4Mask +-- > normalBorderColor =: "#222222" +-- > terminal =: "urxvt" +-- > manageHook =+ (isFullscreen --> doFullFloat) +-- > $(modifyLayout [| smartBorders |]) +-- > focusFollowsMouse =: False +-- > update $ withWindowNavigation (xK_w, xK_a, xK_s, xK_d) +-- > keys =+ [ +-- > ("M-.", sendMessage (IncMasterN 1)), +-- > ("M-,", sendMessage (IncMasterN (-1))), +-- > ("M-p", shellPrompt defaultXPConfig { position = Top }), +-- > ("M-i", prevWS), +-- > ("M-o", nextWS), +-- > ("C-S-q", return ()), +-- > ("<XF86AudioLowerVolume>", spawn "amixer set Master 5%-"), +-- > ("<XF86AudioRaiseVolume>", spawn "amixer set Master unmute 5%+"), +-- > ("XF86AudioMute", spawn "amixer set Master toggle") ] hunk ./xmonad-contrib.cabal 64 extensions: ForeignFunctionInterface cpp-options: -DXFT

- build-depends: mtl >= 1 && < 3, unix, X11>=1.6 && < 1.7, xmonad>=0.10.1 && < 0.11, utf8-string + build-depends: mtl >= 1 && < 3, unix, X11>=1.6 && < 1.7, xmonad>=0.10.1 && < 0.11, utf8-string, + fclabels, template-haskell

if true ghc-options: -fwarn-tabs -Wall hunk ./xmonad-contrib.cabal 146 XMonad.Config.Droundy XMonad.Config.Gnome XMonad.Config.Kde + XMonad.Config.Prime XMonad.Config.Sjanssen XMonad.Config.Xfce XMonad.Hooks.CurrentWorkspaceOnTop } [minor tweaks to X.C.Prime Devin Mullins **20120924062020 Ignore-this: 367385e5c3612f3bcdb7e28acad42513 ] { hunk ./XMonad/Config/Prime.hs 87 import Control.Monad.State.Lazy (StateT, execStateT) import qualified Data.Map as M import Data.Label (lens, (:->)) -import Data.Label.PureM ((=:), (=.), gets) -import Data.Monoid (All, Monoid, mappend) +import Data.Label.PureM ((=:), (=.)) +import Data.Monoid (All) import Language.Haskell.TH (Exp, Q)

hunk ./XMonad/Config/Prime.hs 91 -import XMonad hiding (xmonad, XConfig(..), gets) +import XMonad hiding (xmonad, XConfig(..), gets, modify) import XMonad (XConfig(XConfig)) hunk ./XMonad/Config/Prime.hs 93 -import qualified XMonad as X (xmonad, XConfig(..)) +import qualified XMonad as X

import XMonad.Util.EZConfig (additionalKeysP, additionalMouseBindings)

hunk ./XMonad/Config/Prime.hs 317 -- On the other hand, 'XMonad.Hooks.DynamicLog.xmobar' returns an @IO (XConfig -- l)@, so we need to use 'update': -- --- > import XMonad.Actions.WindowNavigation +-- > import XMonad.Hooks.DynamicLog -- > ... -- > update $ xmobar -- hunk ./XMonad/Config/Prime.hs 325 -- case, but it doesn't hurt. The dollar sign is like an auto-closing -- parenthesis.)

+modify :: (MonadState s m) => (s -> s) -> m () +modify = X.modify + update :: (XConfig Layout -> IO (XConfig Layout)) -> Prime update f = get >>= io . f >>= put

hunk ./XMonad/Config/Prime.hs 360 l =+ new = l =. (<+> new)

instance Summable (XConfig Layout :-> (Event -> X All)) (Event -> X All) where - l =+ new = do - old <- gets l - l =: \evt -> old evt `mappend` new evt + l =+ new = l =. (<+> new)

instance Summable (XConfig Layout :-> [String]) [String] where l =+ new = l =. (++ new) }

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