Regex 用Haskell正则表达式库替换/替换

在Haskell中是否有用于搜索并替换为正则表达式的高级API？我特别关注

Text.Regex.TDFA

或

Text.Regex.Posix

包。我真的想要一种：

f :: Regex -> (ResultInfo -> m String) -> String -> m String

例如，用“猫”代替“狗”，你可以写

runIdentity . f "dog" (return . const "cat")    -- :: String -> String

或者用monad做更高级的事情，比如计算事件发生次数等

---

这方面的Haskell文档非常缺乏。一些低级API注释是。

我不知道有任何现有函数可以创建此功能，但我认为我最终会使用类似的东西来模拟它：

replaceAll :: RegexLike r String => r -> (String -> String) -> String -> String
replaceAll re f s = start end
  where (_, end, start) = foldl' go (0, s, id) $ getAllMatches $ match re s
        go (ind,read,write) (off,len) =
          let (skip, start) = splitAt (off - ind) read 
              (matched, remaining) = splitAt len matched 
          in (off + len, remaining, write . (skip++) . (f matched ++))

replaceAllM :: (Monad m, RegexLike r String) => r -> (String -> m String) -> String -> m String
replaceAllM re f s = do
  let go (ind,read,write) (off,len) = do
      let (skip, start) = splitAt (off - ind) read 
      let (matched, remaining) = splitAt len matched 
      replacement <- f matched
      return (off + len, remaining, write . (skip++) . (replacement++))
  (_, end, start) <- foldM go (0, s, return) $ getAllMatches $ match re s
  start end

replaceAll:：RegexLike r String=>r->（String->String）->String->String
replaceAll re f s=开始-结束
其中（u，end，start）=foldl'go（0，s，id）$getAllMatches$match re s
去（读，写）（关，兰）=
let（skip，start）=splitAt（off-ind）read
（匹配，剩余）=在len匹配时拆分
在（off+len，剩余，写入）中。（跳过++）（f匹配++）
replaceAllM:：（Monad m，RegexLike r String）=>r->（String->m String）->String->m String
replaceAllM re f s=do
放手，放手
let（skip，start）=splitAt（off-ind）read
let（匹配，剩余）=在len匹配时拆分
更换包装内的
regex compat
如何

Prelude> import Text.Regex (mkRegex, subRegex)

Prelude> :t mkRegex
mkRegex :: String -> Regex

Prelude> :t subRegex
subRegex :: Regex -> String -> String -> String

Prelude> subRegex (mkRegex "foo") "foobar" "123"
"123bar"

也许这种方法适合你

import Data.Array (elems)
import Text.Regex.TDFA ((=~), MatchArray)

replaceAll :: String -> String -> String -> String        
replaceAll regex new_str str  = 
    let parts = concat $ map elems $ (str  =~  regex :: [MatchArray])
    in foldl (replace' new_str) str (reverse parts) 

  where
     replace' :: [a] -> [a] -> (Int, Int) -> [a]
     replace' new list (shift, l)   = 
        let (pre, post) = splitAt shift list
        in pre ++ new ++ (drop l post)

基于@rampion的答案，但由于排印错误已修复，因此它不仅仅是
：

您可以从中使用
replaceAll

我建议用“monad的更高级的东西，比如计数事件等”来进行“搜索和替换”

有关如何计数事件的具体示例，请参阅软件包自述

replaceAll :: Regex -> (String -> String) -> String -> String
replaceAll re f s = start end
  where (_, end, start) = foldl' go (0, s, id) $ getAllMatches $ match re s
        go (ind,read,write) (off,len) =
            let (skip, start) = splitAt (off - ind) read 
                (matched, remaining) = splitAt len start 
            in (off + len, remaining, write . (skip++) . (f matched ++))

Prelude> :set -XOverloadedStrings
Prelude> import Data.Text.ICU.Replace
Prelude Data.Text.ICU.Replace> replaceAll "cat" "dog" "Bailey is a cat, and Max is a cat too."
"Bailey is a dog, and Max is a dog too."