Customize the command printing function

[chrismwendt]

Useful for adding color or a prefix like "Running command: " <> cmd <> " ...".

[andreasabel]

Please add test and investigate backwards compatibility, so a decision can be made whether this PR should be merged.

[andreasabel]

Switching from echo to sPrintCommandsFn with standard semantics TIO.hPutStrLn does not seem to preserve the current behavior, see the current definition of echo:

Shelly.hs/src/Shelly/Base.hs

Line 304 in 25a7884

echo msg = traceEcho msg >> liftIO (TIO.putStrLn msg >> hFlush stdout)

[chrismwendt]

Added a test, and I'm pretty sure it's backwards compatible because previously it was TIO.putStrLn and now the default isTIO.hPutStrLn stdout, which is the definition of TIO.putStrLn:

-- | Write a string to 'stdout', followed by a newline.
putStrLn :: Text -> IO ()
putStrLn = hPutStrLn stdout

https://github.com/haskell/text/blob/1.2.4.1/src/Data/Text/IO.hs#L314-L316

[andreasabel]

Thanks for the test!
Also, now the semantics of echo is preserved.

AFAICS, State is an internal data structure not part of the API, so the API is only extended by a new function, not changed, so this could be released as a minor version (1.12.1). Is that right?

Could you formulate a sentence for the changelog?

[chrismwendt]

Added a changelog entry. This adds an option to the API, so users don't have to change their code when they upgrade.

[andreasabel]

So after merging your other PR (#229), there are conflicts...

[chrismwendt]

I'm on it

[chrismwendt]

Fixed conflicts

[andreasabel]

Thanks for the update!

Sorry, I have to request further changes. I remembered that there is also the API Shelly.Lifted which should evolve in sync with Shelly. Could you please extend this API by the new functionality? (That would be echoWith and print_commands_with, I think.)

[chrismwendt]

Updated Lifted

[andreasabel]

Thanks!

I squashed the commits and bumped the version.

Candidate at: https://hackage.haskell.org/package/shelly-1.12.1/candidate/changelog

[andreasabel]

Published: https://hackage.haskell.org/package/shelly-1.12.1