用动态值扩展静态自动完成命令列表 [英] Extending the list of static autocompletion commands with dynamic values
问题描述
我在Haskell中有以下程序，该程序从命令行获取输入并修改mydata变量的状态:
I have following program in Haskell that takes input from command line and modifies state of mydata variable:
{-# LANGUAGE FlexibleInstances, MultiParamTypeClasses, UndecidableInstances #-}
import Text.Regex.PCRE
import System.Console.Haskeline
import System.IO
import System.IO.Unsafe
import Control.Monad.State.Strict
import qualified Data.ByteString.Char8 as B
import Data.Maybe
import Data.List
import qualified Data.Map as M
data MyDataState = MyDataState {
mydata :: [Int],
showEven :: Bool
} deriving (Show)
myfile :: FilePath
myfile = "data.txt"
defaultFlagValue :: Bool
defaultFlagValue = False
saveDataToFile :: [Int] -> IO ()
saveDataToFile _data = withFile myfile WriteMode $ \h -> hPutStr h (unwords $ map show _data)
{-# NOINLINE loadDataFromFile #-}
loadDataFromFile :: [Int]
loadDataFromFile = map read . words $ B.unpack $ unsafePerformIO $ B.readFile myfile
wordList = [":help", ":q", ":commands", ":show", ":save", ":edit", ":new", ":toggleShowEven"]
searchFunc :: String -> [Completion]
searchFunc str = map simpleCompletion $ filter (str `isPrefixOf`) (wordList)
mySettings :: Settings (StateT MyDataState IO)
mySettings = Settings { historyFile = Just "myhist"
, complete = completeWord Nothing " \t" $ return . searchFunc
, autoAddHistory = True
}
help :: InputT (StateT MyDataState IO) ()
help = liftIO $ mapM_ putStrLn
[ ""
, ":help - this help"
, ":q - quit"
, ":commands - list available commands"
, ""
]
commands :: InputT (StateT MyDataState IO) ()
commands = liftIO $ mapM_ putStrLn
[ ""
, ":show - display data"
, ":save - save results to file"
, ":edit - edit data"
, ":new - generate new element "
, ":toggleShowEven - toggle display of even elements"
, ""
]
toggleFlag :: InputT (StateT MyDataState IO) ()
toggleFlag = do
MyDataState mydata flag <- get
put $ MyDataState mydata (not flag)
instance MonadState s m => MonadState s (InputT m) where
get = lift get
put = lift . put
state = lift . state
parseInput :: String -> InputT (StateT MyDataState IO) ()
parseInput inp
| inp =~ "^\\:q" = return ()
| inp =~ "^\\:he" = help >> mainLoop
| inp =~ "^\\:commands" = commands >> mainLoop
| inp =~ "^\\:toggleShowEven" = toggleFlag >> mainLoop
| inp =~ "^\\:show" = do
MyDataState mydata showEven <- get
liftIO $ putStrLn $ unwords $ if showEven
then map show mydata
else map show $ filter odd mydata
mainLoop
| inp =~ "^\\:save" = do
MyDataState mydata _ <- get
liftIO $ saveDataToFile mydata
mainLoop
| inp =~ "^\\:load" = do
put (MyDataState loadDataFromFile defaultFlagValue)
mainLoop
| inp =~ "^\\:new" = do
MyDataState mydata showEven <- get -- reads the state
inputData <- getInputLine "\tEnter data: "
case inputData of
Nothing -> put ( MyDataState [0] showEven )
Just inputD ->
put $ if null mydata
then MyDataState [read inputD] showEven
else MyDataState (mydata ++ [read inputD]) showEven -- updates the state
mainLoop
| inp =~ ":" = do
outputStrLn $ "\nNo command \"" ++ inp ++ "\"\n"
mainLoop
| otherwise = handleInput inp
handleInput :: String -> InputT (StateT MyDataState IO) ()
handleInput inp = mainLoop
mainLoop :: InputT (StateT MyDataState IO ) ()
mainLoop = do
inp <- getInputLine "% "
maybe (return ()) parseInput inp
greet :: IO ()
greet = mapM_ putStrLn
[ ""
, " MyProgram"
, "=============================="
, "For help type \":help\""
, ""
]
main :: IO ((), MyDataState)
main = do
greet
runStateT (runInputT mySettings mainLoop) MyDataState {mydata = [] , showEven = defaultFlagValue}
与上述程序交互的示例:
Example of interaction with the program above:
*Main> main
MyProgram
==============================
For help type ":help"
% :commands
:show - display data
:save - save results to file
:edit - edit data
:new - generate new element
:toggleShowEven - toggle display of even elements
% :show
% :new
Enter data: 1
% :new
Enter data: 2
% :new
Enter data: 3
% :show
1 3
% :toggleShowEven
% :show
1 2 3
%
您可能已经注意到，该程序对典型命令(例如:show，:edit，:new等)使用命令行自动补全功能.
As you might have noticed, this program is using command line autocompletion for typical commands such as :show, :edit, :new, etc.
我的问题正在关注.是否可以使用MyDataState中的值扩展可用于自动补全的命令列表(wordsList变量)?例如，如果mydata包含值1, 2, 3，我希望将其与可用于自动补全的命令一起显示-键入: Tab 时，我将得到以下内容命令列表，而不是仅通过wordsList静态定义的命令列表: :help ， :q ， :commands ， :show ， :save ， :edit ， :new ， :toggleShowEven ， :1 ， :2 ， :3 .如何扩展searchFunc定义以包含在MyDataState中定义的值?有可能吗?
My question is following. Is it possible to extend the list of commands available for autocompletion (wordsList variable) with the values from MyDataState? For example, if mydata contains values 1, 2, 3, I want it to be shown together with commands available for autocompletion - when typing :Tab, I would get the following list of commands instead of just statically defined via wordsList: :help, :q, :commands, :show, :save, :edit, :new, :toggleShowEven, :1, :2, :3. How do I need to extend searchFunc definition to include values defined in MyDataState? Is it possible at all?
推荐答案
在Settings记录中，字段complete的类型为CompletionFunc (StateT MyDataState IO)，这意味着我们可以访问自动完成状态.
In the Settings record, the field complete has type CompletionFunc (StateT MyDataState IO), implying that we have access to the state for autocompletion.
当前mySettings使用的定义
complete = completeWord Nothing " \t" $ return . searchFunc
此return包装了一个纯函数，因此忽略了有状态上下文.我们可以用访问状态的计算来代替它:
This return wraps a pure function, which thus ignores the stateful context. We can replace that with a computation accessing the state:
complete = completeWord Nothing " \t" $ \str -> do
_data <- get
return (searchFunc _data str)
还将searchFunc的类型更改为:
searchFunc :: MyDataState -> String -> [Completion]
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