Is it possible to debug Turtle scripts (equivalent of "-x" flag in bash)?

Question

I've recently started using Haskell Turtle library to replace some of my shell scripts.

Is there a way to somehow enable echoing of built in Turtle commands (like cd) ala set -x in bash scripts? I find it quite problematic to debug Turtle scripts in cases where many commands are executed and one of them fails with exception (like cp command with Exception:openBinaryFile: does not exist). Alternatively do you have some recommendation how to quickly isolate problems like these, so that I don't have to intersperse puStrLn/echo commands throughout my script?

Answer 1

Sadly, it is not possible, as turtle does not provide tracing. For example, mv is defined only with Haskell function (no shell call), so there is no way to print anything when it is ran:

mv :: MonadIO io => FilePath -> FilePath -> io ()
mv oldPath newPath = liftIO (Filesystem.rename oldPath newPath)

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This limitation mentioned in the documentation, where the author recommends to take a look at Shelly, which is similar but provide extra features:

turtle is designed to be beginner-friendly, but as a result lacks certain features, like tracing commands. If you feel comfortable using turtle then you should also check out the Shelly library which provides similar functionality.