Counter proposal: Do not include whenM and ifM

[Bardur Arantsson]

On 2014-04-21 18:55, Tom Ellis wrote:
> (Since Carter asked for new proposals to be started in a separate thread I
> am reposting the contents of an earlier message with additions)
> 
> My (counter) proposal is that 'whenM' and 'ifM' *not* be added anywhere
> (under any names) because there is a completely generic alternative to these
> adhoc additions that warrants further investigation.
> 
> The executive summary is that instead of introducing another function
> 'unlessM' to be used like this
> 
>     unlessM doesDirectoryExist path $ do
>         putStrLn $ "Creating directory " ++ path
>         createDirectory path
> 
> we just use the existing 'unless' and a new generic combinator (<*>|) like
> this
> 
>     unless <$> doesDirectoryExist path <*>| pure (do
>         putStrLn $ "Creating directory " ++ path
>         createDirectory path)
> 

-1, completely ignores the pedagogic aspects of the original proposal.