Haskell QuasiQuotes Text.RawString.QQ插值

Question

我如何像这样进行插值：

{-# LANGUAGE QuasiQuotes #-}
import Text.RawString.QQ

myText :: Text -> Text
myText myVariable = [r|line one
line two
line tree
${ myVariable }
line five|]

myText' :: Text
myText' = myText "line four"

${ myVariable }打印为文字，而不是插值，在这种情况下，我可以做一些类似于插值的事情吗？

Answer 1

Quasi r不实现插值。它只适用于原始字符串。您需要另一个准引号。

完整代码：

{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE QuasiQuotes #-}

import Data.Text (Text)
import Text.RawString.QQ (r)
import NeatInterpolation (text)

rQuote :: Text -> Text
rQuote myVariable = [r|line one
line two
line tree
${ myVariable }
line five|]

neatQuote :: Text -> Text
neatQuote myVariable = [text|line one
line two
line tree
$myVariable
line five|]

rText, neatText :: Text
rText    = rQuote    "line four"
neatText = neatQuote "line four"

在ghci中

*Main> import Data.Text.IO as TIO
*Main TIO> TIO.putStrLn rText
line one
line two
line tree
${ myVariable }
line five
*Main TIO> TIO.putStrLn neatText
line one
line two
line tree
line four
line five

Answer 2

我实现目标的唯一方法就是连接：

{-# LANGUAGE QuasiQuotes #-}
import Text.RawString.QQ

myText :: Text -> Text
myText myVariable = [r|line one
line two
line tree
|] <> myVariable <> [r|
line five|]

myText' :: Text
myText' = myText "line four"