hledger/hledger-ui/Hledger/UI/Editor.hs
Simon Michael 43159f4fea ;ui: E key: comment
[ci skip]
2019-12-15 11:07:26 -08:00

110 lines
4.1 KiB
Haskell

{- | Editor integration. -}
-- {-# LANGUAGE OverloadedStrings #-}
module Hledger.UI.Editor (
-- TextPosition
endPosition
,runEditor
,runIadd
)
where
import Control.Applicative ((<|>))
import Safe
import System.Environment
import System.Exit
import System.FilePath
import System.Process
import Hledger
-- | A position we can move to in a text editor: a line and optional column number.
-- Line number 1 or 0 means the first line. A negative line number means the last line.
type TextPosition = (Int, Maybe Int)
-- | The text position meaning "last line, first column".
endPosition :: Maybe TextPosition
endPosition = Just (-1,Nothing)
-- | Run the hledger-iadd executable on the given file, blocking until it exits,
-- and return the exit code; or raise an error.
-- hledger-iadd is an alternative to the built-in add command.
runIadd :: FilePath -> IO ExitCode
runIadd f = runCommand ("hledger-iadd -f " ++ f) >>= waitForProcess
-- | Run the user's preferred text editor (or try a default editor),
-- on the given file, blocking until it exits, and return the exit
-- code; or raise an error. If a text position is provided, the editor
-- will be focussed at that position in the file, if we know how.
runEditor :: Maybe TextPosition -> FilePath -> IO ExitCode
runEditor mpos f = editFileAtPositionCommand mpos f >>= runCommand >>= waitForProcess
-- | Get a shell command line to open the user's preferred text editor
-- (or a default editor) on the given file, and to focus it at the
-- given text position if one is provided and if we know how.
-- We know how to focus on position for: emacs, vi, nano.
-- We know how to focus on last line for: vi.
--
-- Some tests: With line and column numbers specified,
-- @
-- if EDITOR is: the command should be:
-- ------------- -----------------------------------
-- notepad notepad FILE
-- vi vi +LINE FILE
-- vi + FILE # negative LINE
-- emacs emacs +LINE:COL FILE
-- emacs FILE # negative LINE
-- (unset) emacsclient -a '' -nw +LINE:COL FILE
-- emacsclient -a '' -nw FILE # negative LINE
-- @
--
-- How to open editors at the last line of a file:
-- @
-- emacs: emacs FILE -f end-of-buffer
-- emacsclient: can't
-- vi: vi + FILE
-- @
--
editFileAtPositionCommand :: Maybe TextPosition -> FilePath -> IO String
editFileAtPositionCommand mpos f = do
let f' = singleQuoteIfNeeded f
editcmd <- getEditCommand
let editor = lowercase $ takeFileName $ headDef "" $ words' editcmd
let positionarg =
case mpos of
Just (l, mc)
| editor `elem` [
"ex",
"vi","vim","view","nvim","evim","eview",
"gvim","gview","rvim","rview","rgvim","rgview"
] -> plusAndMaybeLine l mc
Just (l, mc)
| editor `elem` ["emacs", "emacsclient"] -> plusLineAndMaybeColonColumnOrEnd l mc
Just (l, mc)
| editor `elem` ["nano"] -> plusLineAndMaybeCommaColumn l mc
_ -> ""
where
plusAndMaybeLine l _ = "+" ++ if l >= 0 then show l else ""
plusLineAndMaybeCommaColumn l mc = "+" ++ show l ++ maybe "" ((","++).show) mc
plusLineAndMaybeColonColumnOrEnd l mc
| l >= 0 = "+" ++ show l ++ maybe "" ((":"++).show) mc
| otherwise = ""
-- otherwise = "-f end-of-buffer"
-- XXX Problems with this:
-- it must appear after the filename, whereas +LINE:COL must appear before
-- it works only with emacs, not emacsclient
return $ unwords [editcmd, positionarg, f']
-- | Get the user's preferred edit command. This is the value of the
-- $HLEDGER_UI_EDITOR environment variable, or of $EDITOR, or a
-- default ("emacsclient -a '' -nw", which starts/connects to an emacs
-- daemon in terminal mode).
getEditCommand :: IO String
getEditCommand = do
hledger_ui_editor_env <- lookupEnv "HLEDGER_UI_EDITOR"
editor_env <- lookupEnv "EDITOR"
let Just cmd = hledger_ui_editor_env <|> editor_env <|> Just "emacsclient -a '' -nw"
return cmd