XMonad.Util.Run

This module provides several commands to run an external process. Additionally, it provides an abstraction—particularly geared towards programs like terminals or Emacs—to specify these processes from XMonad in a compositional way.

Originally, this module was composed of functions formerly defined in XMonad.Util.Dmenu (by Spencer Janssen), XMonad.Util.Dzen (by [e-mail]) and XMonad.Util.RunInXTerm (by Andrea Rossato).

Usage

You can use this module by importing it in your xmonad.hs

import XMonad.Util.Run

It then all depends on what you want to do:

• If you want to compositionally spawn programs, see the relevant extended documentation.
• For an example usage of runInTerm see XMonad.Prompt.Ssh.
• For an example usage of runProcessWithInput see XMonad.Util.Dmenu, or XMonad.Prompt.Shell.
• For an example usage of runProcessWithInputAndWait see XMonad.Util.Dzen.

runProcessWithInput :: MonadIO m => FilePath -> [String] -> String -> m String

Returns the output.

runProcessWithInputAndWait :: MonadIO m => FilePath -> [String] -> String -> Int -> m ()

Wait is in μ (microseconds)

safeSpawn :: MonadIO m => FilePath -> [String] -> m ()

safeSpawn bypasses spawn, because spawn passes strings to /bin/sh to be interpreted as shell commands. This is often what one wants, but in many cases the passed string will contain shell metacharacters which one does not want interpreted as such (URLs particularly often have shell metacharacters like '&' in them). In this case, it is more useful to specify a file or program to be run and a string to give it as an argument so as to bypass the shell and be certain the program will receive the string as you typed it.

Examples:

, ((modm, xK_Print), unsafeSpawn "import -window root $HOME/xwd-$(date +%s)$$.png")
, ((modm, xK_d    ), safeSpawn "firefox" [])

Note that the unsafeSpawn example must be unsafe and not safe because it makes use of shell interpretation by relying on $HOME and interpolation, whereas the safeSpawn example can be safe because Firefox doesn't need any arguments if it is just being started.

safeSpawnProg :: MonadIO m => FilePath -> m ()

Simplified safeSpawn; only takes a program (and no arguments):

, ((modm, xK_d    ), safeSpawnProg "firefox")

unsafeSpawn :: MonadIO m => String -> m ()

An alias for spawn; the name emphasizes that one is calling out to a Turing-complete interpreter which may do things one dislikes; for details, see safeSpawn.

runInTerm :: String -> String -> X ()

Open a terminal emulator. The terminal emulator is specified in the default configuration as xterm by default. It is then asked to pass the shell a command with certain options. This is unsafe in the sense of unsafeSpawn

safeRunInTerm :: String -> String -> X ()

Run a given program in the preferred terminal emulator; see runInTerm. This makes use of safeSpawn.

seconds :: Rational -> Int

Multiplies by ONE MILLION, for functions that take microseconds.

Use like:

(5.5 `seconds`)

In GHC 7 and later, you must either enable the PostfixOperators extension (by adding

{-# LANGUAGE PostfixOperators #-}

to the top of your file) or use seconds in prefix form:

seconds 5.5

spawnPipe :: MonadIO m => String -> m Handle

Launch an external application through the system shell and return a Handle to its standard input. Note that the Handle is a text Handle using the current locale encoding.

spawnPipeWithLocaleEncoding :: MonadIO m => String -> m Handle

Same as spawnPipe.

spawnPipeWithUtf8Encoding :: MonadIO m => String -> m Handle

Same as spawnPipe, but forces the UTF-8 encoding regardless of locale.

spawnPipeWithNoEncoding :: MonadIO m => String -> m Handle

Same as spawnPipe, but forces the char8 encoding, so unicode strings need encodeString. Should never be needed, but some X functions return already encoded Strings, so it may possibly be useful for someone.

Compositionally Spawning Processes

To use the provided EDSL, you must first add the spawnExternalProcess combinator to your xmonad configuration, like so:

main = xmonad $ … $ spawnExternalProcess def $ … $ def

See ProcessConfig for a list of all default configuration options, in case you'd like to change them—especially if you want to make use of the Emacs integration.

After that, the real fun begins! The format for spawning these processes is always the same: a call to proc, its argument being a bunch of function calls, separated by the pipe operator (>->). You can just bind the resulting function to a key; no additional plumbing required. For example, using XMonad.Util.EZConfig syntax and with terminal = "alacritty" in you XMonad configuration, spawning a ghci session with a special class name, "calculator", would look like

("M-y", proc $ inTerm >-> setXClass "calculator" >-> execute "ghci")

which would translate, more or less, to /usr/bin/sh -c "alacritty --class calculator -e ghci". The usefulness of this notation becomes apparent with more complicated examples:

proc $ inEmacs
   >-> withEmacsLibs [OwnFile "mailboxes"]
   >-> execute (elispFun "notmuch")
   >-> setFrameName "mail"

This is equivalent to spawning

emacs -l /home/slot/.config/emacs/lisp/mailboxes.el
      -e '(notmuch)'
      -F '(quote (name . "mail"))'

Notice how we did not have to specify the whole path to mailboxes.el, since we had set the correct emacsLispDir upon starting xmonad. This becomes especially relevant when running Emacs in batch mode, where one has to include [M,Non-GNU]ELPA packages in the call, whose exact names may change at any time. Then the following

do url <- getSelection  -- from XMonad.Util.XSelection
   proc $ inEmacs
      >-> withEmacsLibs [ElpaLib "dash", ElpaLib "s", OwnFile "arXiv-citation"]
      >-> asBatch
      >-> execute (elispFun $ "arXiv-citation" <> asString url)

becomes

emacs -L /home/slot/.config/emacs/elpa/dash-20220417.2250
      -L /home/slot/.config/emacs/elpa/s-20210616.619
      -l /home/slot/.config/emacs/lisp/arXiv-citation.el
      --batch
      -e '(arXiv-citation "<url-in-the-primary-selection>")'

which would be quite bothersome to type indeed!

A blog post going into some more detail and also explaining how to integrate this new language with the XMonad.Util.NamedScratchpad module is available here.

Configuration and Running

data ProcessConfig

Additional information that might be useful when spawning external programs.

Constructors

ProcessConfig

Fields

• editor :: !String

  Default editor. Defaults to "emacsclient -c -a ''".

• emacsLispDir :: !FilePath

  Directory for your custom Emacs lisp files. Probably user-emacs-directory or user-emacs-directory/lisp. Defaults to "~/.config/emacs/lisp/"

• emacsElpaDir :: !FilePath

  Directory for all packages from [M,Non-GNU]ELPA; probably user-emacs-directory/elpa. Defaults to "~/.config/emacs/elpa".

• emacs :: !String

  Standalone Emacs executable; this should not be emacsclient since, for example, the client does not support --batch mode. Defaults to "emacs".

Instances

Default ProcessConfig

Defined in XMonad.Util.Run

Methods

def :: ProcessConfig

type Input = ShowS

Convenient type alias.

spawnExternalProcess :: forall (l :: Type -> Type). ProcessConfig -> XConfig l -> XConfig l

Given a ProcessConfig, remember it for spawning external processes later on.

proc :: X Input -> X ()

Spawn a completed input.

getInput :: X Input -> X String

Get the completed input string.

toInput :: String -> X Input

Create an effectful Input from a String.

Programs

inEditor :: X Input

Use the editor.

inTerm :: X Input

Use the terminal.

termInDir :: X Input

Spawn the terminal in some directory; it must support the --working-directory option.

inProgram :: String -> X Input

Use the given program.

General Combinators

(>->) :: X Input -> X Input -> X Input infixr 3

Combine inputs together.

(>-$) :: X Input -> X String -> X Input infixr 3

Combine an input with an ordinary string.

(>&&>) :: X Input -> X Input -> X Input infixr 2

a >&&> b glues the different inputs a and b by means of &&. For example,

pure "do something" >&&> pure "do another thing"

would result in do something && do another thing being executed by a shell.

(>||>) :: X Input -> X Input -> X Input infixr 2

Like (>&&>), but with ||.

inWorkingDir :: X Input

Spawn thing in the current working directory. thing must support a --working-directory option.

eval :: String -> X Input

Eval(uate) the argument. Current thing must support a --eval option.

execute :: String -> X Input

Execute the argument. Current thing must support a -e option. For programs such as Emacs, eval may be the safer option; while emacsclient supports -e, the emacs executable itself does not.

Note that this function always wraps its argument in single quotes; see executeNoQuote for an alternative.

executeNoQuote :: String -> X Input

Like execute, but doesn't wrap its argument in single quotes.

setXClass :: String -> X Input

Set the appropriate X class for a window. This will more often than not actually be the instance name.

asString :: String -> String

Treat an argument as a string; i.e., wrap it with quotes.

>>> asString "string"
" \"string\" "

Emacs Integration

data EmacsLib

An Emacs library.

Constructors

OwnFile !String

A file from emacsLispDir.

ElpaLib !String

A directory in emacsElpaDir.

Special !String

Special files; these will not be looked up somewhere, but forwarded verbatim (as a path).

setFrameName :: String -> X Input

Set a frame name for the emacsclient.

Note that this uses the -F option to set the frame parameters alist, which the emacs executable does not support.

withEmacsLibs :: [EmacsLib] -> X Input

Load some Emacs libraries. This is useful when executing scripts in batch mode.

inEmacs :: X Input

Use emacs.

elispFun :: String -> String

Transform the given input into an elisp function; i.e., surround it with parentheses.

>>> elispFun "arxiv-citation URL"
" '( arxiv-citation URL )' "

asBatch :: X Input

Tell Emacs to enable batch-mode.

require :: String -> String

Require a package.

>>> require "arxiv-citation"
"(require (quote arxiv-citation))"

progn :: [String] -> String

Wrap the given commands in a progn. The given commands need not be wrapped in parentheses (but can); this will be done by the function. For example:

>>> progn [require "this-lib", "function-from-this-lib arg", "(other-function arg2)"]
"(progn (require (quote this-lib)) (function-from-this-lib arg) (other-function arg2))"

quote :: String -> String

Quote a symbol.

>>> quote "new-process"
"(quote new-process)"

findFile :: String -> String

Call find-file.

>>> findFile "/path/to/file"
"(find-file \"/path/to/file\" )"

list :: [String] -> String

Make a list of the given inputs.

>>> list ["foo", "bar", "baz", "qux"]
"(list foo bar baz qux)"

saveExcursion :: [String] -> String

Like progn, but with save-excursion.

>>> saveExcursion [require "this-lib", "function-from-this-lib arg", "(other-function arg2)"]
"(save-excursion (require (quote this-lib)) (function-from-this-lib arg) (other-function arg2))"

Re-exports

hPutStr :: Handle -> String -> IO ()

Computation hPutStr hdl s writes the string s to the file or channel managed by hdl.

This operation may fail with:

• isFullError if the device is full; or
• isPermissionError if another system resource limit would be exceeded.

hPutStrLn :: Handle -> String -> IO ()

The same as hPutStr, but adds a newline character.