BUG pretty not working on Windows: "invalid character"

[turbotimon]

Prettyprinter does not work on Windows when printing a special character

ghci> import Prettyprinter
ghci> pretty "hello"
hello
ghci> pretty "hello λ"
hello *** Exception: <stdout>: hPutChar: invalid argument (invalid character)

• Windows 10
• Tested with PowerShell and CMD
• prettyprinter-1.7.1 (stack snapshot lts-20.10)

[sjakobi]

What happens if you just input "hello λ"?

Did you configure your terminal to use UTF-8?

[turbotimon]

I looks like UTF-8 generally work in PS and CMD. In GHCI it get's escaped (but no error):

PS C:\Users\user> "hello ?"
hello λ
PS C:\Users\user> ghci
GHCi, version 9.2.5: https://www.haskell.org/ghc/  :? for help
ghci> "hello λ"
"hello \955"

I know other people having this issue on windows, it therefore seems not to be a isolated problem with my system.

[turbotimon]

I found a workaround by changing the codepage of the PowerShell or cmd.exe: chcp 65001

(this link may be also useful)

[das-g]

Here seems to be workaround that can probably be implemented in programs and libraries (rather than by the end user).

[sjakobi]

I'm not sure that prettyprinter should try to set encodings on Windows.

Maybe we can add a bit of documentation about this though. Where would you expect to find it?

[turbotimon]

Probably on the main page / readme?