[Haskell-cafe] Breaking up long lines

Donald Bruce Stewart dons at cse.unsw.edu.au
Sat Apr 1 21:36:11 EST 2006


miketerrance:
> What is a good technique for breaking up long lines of code (for easier readability)?
> 
> I have been inserting {- -} comments but there must be a better way.  Something like \ in Python?

Can you give an example?

Usually breaking long lines is just a matter of cutting on white space:

    lookupP (a,b) cmd = withModule ircCommands cmd
        (error $ "Parse error: " ++ show cmd) 
        (\m -> do
            privs <- gets ircPrivCommands -- no priv commands can be composed
            when (cmd `elem` privs) $ error "Privledged commands cannot be composed"
            return $ \str -> catchError 
                        (process m a b cmd str)
                        (\ex -> case (ex :: IRCError) of 
                                    (IRCRaised (NoMethodError _)) -> process_ m cmd str
                                    _ -> throwError ex))

once things get too big, use 'where' clauses .
Actually, use 'where' clauses when things aren't too big, anyway :)

There's also a set of programming guidelines here:
    
    http://haskell.org/haskellwiki/Programming_guidelines

-- Don


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