Proposal: die to System.Exit (and/or Prelude)

[John Lato]

+1 to adding 'die' to System.Exit
-1 to adding to Prelude

I've pretty much only wanted this in command-line type programs, but as the
proposal notes, it's very frequently required in that situation.

John L.


On Sat, Dec 14, 2013 at 2:56 AM, Simon Hengel <sol at typeful.net> wrote:

> Hi!
> I propose to add
>
>     die :: String -> IO ()
>     die err = hPutStrLn stderr err >> exitFailure
>
> to System.Exit.
>
> Reasoning:
>
> (1) It's a frequently required functionality.  Almost every command-line
>     program has code similar to this.
>
> (2) The definition is relatively short, but in addition to the
>     definition, you need two import statements.
>
> (3) It's frequently done wrong (e.g. writing to stdout instead of
>     stderr, or not using exitFailure, or both).
>
> I haven't done any extensive research on Hackage, but I quickly looked
> at Haddock.  Here we have a definition of die [1], but we also print to
> stdout at a couple of place and then call exitFailure [2].
>
> Personally, I think it should be re-exported from Prelude.  But this may
> be controversial.  So let's have two separate votes:
>
> Add System.Exit.die:            +1
> Re-export it from Prelude:      +1
>
> (discussion until December, 28th)
>
> Cheers,
> Simon
>
> [1]
> https://github.com/ghc/haddock/blob/8d4c94ca5a969a5ebbb791939fb0195dc672429e/src/Haddock/Utils.hs#L303
> [2]
> https://github.com/ghc/haddock/blob/c6faeae064668125721b0d5e60f067f90c538933/src/Haddock.hs#L87
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