Where pipes IO replaces lazy IO, Producer Text IO r replaces lazy Text. The official IO of this package and the pipes ecosystem generally would use the IO functions in Pipes.ByteString and the encoding and decoding material in Pipes.Text.Encoding.

The streaming functions exported here, namely, readFile, writeFile, fromHandle, toHandle, stdin and stdout simplify this and use the system encoding on the model of Data.Text.IO and Data.Text.Lazy.IO Some caveats described below.

The main points are as in Pipes.ByteString:

A Handle can be associated with a Producer or Consumer according as it is read or written to.

import Pipes
import qualified Pipes.Text as Text
import qualified Pipes.Text.IO as Text
import System.IO

main =
    withFile "inFile.txt"  ReadMode  $ \hIn  ->
    withFile "outFile.txt" WriteMode $ \hOut ->
    runEffect $ Text.fromHandle hIn >-> Text.toHandle hOut

To stream from files, the following is perhaps more Prelude-like (note that it uses Pipes.Safe):

import Pipes
import qualified Pipes.Text as Text
import qualified Pipes.Text.IO as Text
import Pipes.Safe

main = runSafeT $ runEffect $ Text.readFile "inFile.txt" >-> Text.writeFile "outFile.txt"

Finally, you can stream to and from stdin and stdout using the predefined stdin and stdout pipes, as with the following "echo" program:

main = runEffect $ Text.stdin >-> Text.stdout

These programs, unlike the corresponding programs written with the line-based functions, will pass along a 1 terabyte line without affecting memory use.

The operations exported here are a convenience, like the similar operations in Data.Text.IO (or rather, Data.Text.Lazy.IO, since, again, Producer Text m r is 'effectful text' and something like the pipes equivalent of lazy Text.)

• Like the functions in Data.Text.IO, they attempt to work with the system encoding.
• Like the functions in Data.Text.IO, they significantly slower than ByteString operations. Where you know what encoding you are working with, use Pipes.ByteString and Pipes.Text.Encoding instead, e.g. view utf8 Bytes.stdin instead of Text.stdin
• Like the functions in Data.Text.IO , they use Text exceptions, not the standard Pipes protocols.