[Haskell] Read the contents from the clipboard in Haskell

有時候只是想要做一點簡單的事情的時候，其實會直接貼上 string 做處理。但是因為不知道怎麼在 ghci 上貼入 multiple line string，所以想到可以直接讀取複製的內容直接做處理。

在 Mac OSX 裡有一個相當好用的指令是 pbpaste，可以直接蛉出在剪貼簿中的指令。開一個 subprocess 把指令的 output pipe 進來就可以了。嘗試如下。

	-- Read the contents of clipboard
	-- Ref: http://stackoverflow.com/questions/1712347/closest-equivalent-to-subprocess-communicate-in-haskell
	import System.Process
	processData :: String -> String
	processData = (id :: String -> String)
	processPaste :: (String -> String) -> IO ()
	processPaste pd = do
	let cmd = "pbpaste"
	args = []
	instr = []
	(rc, out, err) <- readProcessWithExitCode cmd args instr
	putStrLn $ pd out

view raw read_pbpaste.hs hosted with ❤ by GitHub

嘗試執行結果如下

Prelude> :l read_pbpaste.hs
[1 of 1] Compiling Main             ( read_pbpaste.hs, interpreted )
Ok, modules loaded: Main.
*Main> import Data.Char
*Main Data.Char> processPaste Data.Char.to
Data.Char.toLower  Data.Char.toTitle  Data.Char.toUpper
*Main Data.Char> processPaste $ map Data.Char.toUpper
Loading package array-0.4.0.1 ... linking ... done.
Loading package deepseq-1.3.0.1 ... linking ... done.
Loading package filepath-1.3.0.1 ... linking ... done.
Loading package old-locale-1.0.0.5 ... linking ... done.
Loading package time-1.4.0.1 ... linking ... done.
Loading package bytestring-0.10.0.2 ... linking ... done.
Loading package unix-2.6.0.1 ... linking ... done.
Loading package directory-1.2.0.1 ... linking ... done.
Loading package process-1.1.0.2 ... linking ... done.
ING PACKAGE ARRAY-0.4.0.1 ... LINKING ... DONE.
LOADING PACKAGE DEEPSEQ-1.3.0.1 ... LINKING ... DONE.
LOADING PACKAGE FILEPATH-1.3.0.1 ... LINKING ... DONE.
LOADING PACKAGE OLD-LOCALE-1.0.0.5 ... LINKING ... DONE.
LOADING PACKAGE TIME-1.4.0.1 ... LINKING ... DONE.
LOADING PACKAGE BYTESTRING-0.10.0.2 ... LINKING ... DONE.
LOADING PACKAGE UNIX-2.6.0.1 ... LINKING ... DONE.
LOADING PACKAGE DIRECTORY-1.2.0.1 ... LINKING ... DONE.
LOADING PACKAGE PROCESS-1.1.0.2 ... LINKING ... DONE.
HTTPS://EN.WIKIPEDIA.ORG/WIKI/CONTINUATION-PASSING_STYLE
*Main Data.Char>

---

2013/09/08 09:17 AM 早上試一下，還可以這樣子幹也蠻方便的

Prelude System.Process> putStrLn =<< readProcess "pbpaste" [] []
http://hackage.haskell.org/packages/archive/process/1.0.1.1/doc/html/System-Process.html
Prelude System.Process> import Data.Char
Prelude System.Process Data.Char> putStrLn . (map toUpper) =<< readProcess "pbpaste" [] []
HTTP://HACKAGE.HASKELL.ORG/PACKAGES/ARCHIVE/PROCESS/1.0.1.1/DOC/HTML/SYSTEM-PROCESS.HTML

所以想要寫完全沒有彈性的碼可以這樣子寫。

	processPaste' :: (String -> String) -> IO ()
	processPaste' pd = putStrLn . pd =<< readProcess "pbpaste" [] []

view raw read_pbpaste_2.hs hosted with ❤ by GitHub