+ ln -s ~/Library/Haskell/logs/world ~/.cabal
+
+ Now I can find a link to what Cabal has done inside cabal's own folder, without needing to remember or hunt down where the hell on my disk that information has been stored. (Alright, to be honest, you can skip this whole step if you want. But I recommend doing it.)
+
+3. Still assuming you have Cabal, type the following in a Terminal:
+
+ cabal update
+ cabal install --user ghc-paths semigroups hoogle
+
+4. If you haven't already downloaded and installed the Juli8 libraries as described in Step 4 under the earlier OCaml section, do that now. Also type the following lines in a Terminal:
+
+ ln -s ~/.juli8/haskell ~/.ghc/juli8
+
+5. Check to see whether any of the following files exist on your system. `$HOME` will be some directory like `/Users/jim` or `/home/jim` or `C:/Documents\ and\ Settings/jim`:
+
+ * `$HOME/.ghci`
+ * `$HOME/.ghc/ghci.conf`
+ * `$HOME/"Application Data"/ghc/ghci.conf`
+
+ If you find such a file, you will add lines to it in the next step. If you don't find such a file, create one.
+
+6. Add these lines to the `.ghci` or `ghci.conf` file identified in the previous step:
+
+ -- reads ghci commands from any file named in $GHCIRC
+ :cmd (System.Environment.getEnvironment >>= maybe (return "") readFile . lookup "GHCIRC")
+
+ -- special :commands from Juli8
+ :{
+ :cmd do { dot_ghc <- System.Directory.getAppUserDataDirectory "ghc";
+ let { juli8 = dot_ghc ++ "/juli8";
+ cmds = juli8 ++ "/commands" };
+ juli8_exists <- System.Directory.doesDirectoryExist juli8;
+ cmds_exists <- System.Directory.doesFileExist cmds;
+ Control.Monad.when cmds_exists $ putStrLn "Loading juli8/commands ...";
+ return $ unlines $ if cmds_exists then [":set -i"++juli8, ":script "++cmds] else if juli8_exists then [":set -i"++juli8] else [] }
+ :}
+
+ :def! url (\l->return $ ":!open "++l)
+ -- :set editor vim
+ -- :set +m -- for multiline input
+ -- :set +t -- to print types after each binding
+
+ :load Juli8
+ :mod Juli8
+
+ You may want to uncomment the `:set editor vim` line, but only if you know how to use the text editor `vim`. Other text editors you may be familiar with, and can use here are:
+
+ :set editor emacs
+ :set editor nano
+ :set editor open -a TextEdit -- Mac-only
+ :set editor bbedit -- Mac-only, see http://www.barebones.com/support/bbedit/cmd-line-tools.html
+ :set editor mate -- Mac-only, see http://manual.macromates.com/en/using_textmate_from_terminal.html
+ -- for Windows, use one of https://wiki.haskell.org/Windows#Editors
+
+ You may want to uncomment the `:set +m` line. What this does is let you type multi-line commands in the `ghci` sessions. There is a different way to do that, where you type like this:
+
+ :{
+ multiline
+ command
+ :}
+
+ but that's pretty cumbersome. The downside of having `:set +m` on is that sometimes you'll have to type an extra blank line before `ghci` will respond to your input.
+
+If everything works, then when you start up GHCi, you should see a prompt like this:
+
+ Prelude Juli8>
+
+
+## What do I get from Juli8 for Haskell? ##
+
+There are two or three benefits that Juli8 provides for Haskell, and they're not a big deal. If you're already a seasoned Haskell user, you may or may not find them helpful.
+
+First, Juli8 comes with a bunch of extra `:commands` to use at the GHCi prompt. You can see a list of what it installs by typing `:?`. Some of the commands listed in `:?` were already present before Juli8 arrived, and are just here collected and explained in a way I find more helpful. Others are provided by Juli8 itself. Many of these are based on commands already published elsewhere on Haskell wikis and so on, so you may have installed some versions of them already yourself. I'll leave it to you to pick and choose whether anything that comes with Juli8 suits your further needs.
+
+I developed these `:commands` on a Mac, and expect that some of the assumptions I made won't work on other systems. As the library matures, we'll try to make it work for a broader range of systems, or give specific instructions about how to customize it.
+
+The command `:help` will give you the old, official help text, that doesn't show the extra commands installed by Juli8.
+
+Second, Juli8 comes with a module/library that collects together a number of elements from scattered other locations in the Haskell libraries. These include the Semigroup libraries you installed in Step 3 of the above instructions, which you should use in place of Haskell's standard Data.Monoid libraries. Note that the Semigroup library provides `First a` and `Last a` types that differ from the types of the same name in Data.Monoid. Juli8 also provides `OptFirst a` and `OptLast a` types that behave more like the `First a` and `Last a` types from Data.Monoid. It also provides analogous types `OptMax a` and `OptMin a`. (If you don't know what any of this means, don't worry about it.)
+
+Third, Juli8 comes with a module/library `IOPlus` that isn't loaded by default, but which you can load manually by saying `:add IOPlus`. This provides instances to make `IO a` a Monoid when `a` is, and to make `IO` act like an instance of the Alternative and MonadPlus typeclass. This has some limitations, and can't be done perfectly, which is why it isn't done in the standard libraries. There's also an `IOFirst` and an `IOLast`. This is more experimental than the rest of the stuff in Juli8 and may well change or be removed. I'll explain it and refine it another time.