Thanks!

I think compilation is a great tool for type- and syntax- checking a Haskell script, but to me, to remain a script, the actual executable has to be the source code, not a compiled binary. That way, I can, as a reader of scripts, tell what a script does (and how it does it) just by looking at it, instead of trying to track down the matching executable. There’s a bunch of times where I want to
* copy some of the behaviour of an existing script
* trace through a particular script to see if it’s got a bug, or if I’m misunderstanding its use.

I do these tasks and tasks like them time and time again with shell code. And though Haskell, and good practices like sensible error reporting will help somewhat, it’s no substitute for a human readable shell script.

So I’ll be sticking with runhaskell.

Thanks!

new | old == 100 = 0
| otherwise = 100

It gives me a conflicting definition error.

Cool article ;-) Thanks.

I think that on slide 25:

instance MonadError IO

should be

instance MonadError IOError IO

Also, it’s not clear to me what the ErrorT monad transformer buys you in:

newtype Shell a = Shell { runShell :: ErrorT String IO a }

since you’re ignoring the internal Either type from ErrorT. It is just that you get a throwError that you can use with a String instead of with an IOError?

System.Process