Hello, I pleased to announce that Happstack Irregular News Issue #2 is now available. You can view it online at: http://www.happstack.com/C/ViewPage/12 Or continue reading the rest of this message. Happstack Irregular News Issue #2 ================================= Hello! It is I, your editor Jeremy Shaw. I am pleased to bring you Happstack Irregular News Issue #2. Some exciting things have happened since the last issue! clckwrks -------- The biggest news since the last issue is the release of clckwrks: [clckwrks](http://www.clckwrks.com/) clckwrks is a Haskell-based blog and CMS framework with support for editing pages via the browser plus downloadable themes and plugins. clckwrks is now powering happstack.com and clckwrks.com. We are currently focusing on making the clckwrks blogging portion solid. We have moved the official Happstack blog to clckwrks in order to encourage us to make it better :) If you want to help out, you can [browse our bug list](http://www.clckwrks.com/B/Timeline) and find something to take action on. We are more than happy to provide guidance and other assistance. reform ------ The other new big release was [reform](http://www.happstack.com/C/ViewPage/11). `reform` is a form generation library that continues in the footsteps of `formlets` and `digestive-functors <= 0.2`. `digestive-functors 0.3` has gone off to explore a different direction, and we wanted to continue pushing the development in this direction. There are still many ideas we can share between the two libraries. Two changes we want to make in the next release include: 1. switch to `Bifunctors` package instead of homebrewed `IndexedApplicative` (thanks to Leonid Onokhov for pointing that out). (Another alternative might be `index-core`, though it does not yet export the `Applicative` instances). 2. consider using a `Free Applicative` / `Operational Applicative` for implementing the `reform` applicative instances. `digestive functors 0.3` does something like this and Jasper Van der Jeugt said it was very beneficial and we should try it in `reform` as well. happstack-yui ------------- Dag Odenhall has released `happstack-yui`, which makes it easy to use YUI with Happstack. According the YUI website: "YUI is a free, open source JavaScript and CSS framework for building richly interactive web applications." [happstack-yui](http://www.happstack.com/docs/happstack-yui-7351.4.1/doc/html/happstack-yui/...) [YUI website](http://yuilibrary.com/) HSX --- Niklas Broberg and I (Jeremy Shaw) did some work on HSX. It now builds with GHC 7.4 and we also fixed some hidden bugs in `HSX.Transform`. One thing we have been experimenting with is a `QuasiQuoter` for HSX. A demo version can be found here: darcs get http://src.seereason.com/hsx-qq/ The QQ provides an alternative to the `trhsx` preprocessor and allows you to write things like: html :: (XMLGenerator m) => XMLGenT m (XMLType m) html = [hsx| <p class="foo"><% map toUpper "hello, world!" %></p> |] This should be included in the next release of HSX. The next release of HSX will also contain a major refactoring of the packages. Mostly we are just planning to move modules into different packages and divide things up differently. One major benefit of the new arrangement is that you will no longer be required to install `HJavaScript` and `HJScript` even though you probably never use them. Other Minor Fixes ----------------- * changed types in `happstack-lite` so that `serveFile` and `asContentType` work better together, and added `guessContentType`, `MimeMap`, `mimeType` * patched `happstack-jmacro` to work with older versions of `template haskell` * tweaks to `ixset.cabal` so that it does not require the latest `Cabal` to build acid-state and hackage2 ----------------------- I have started research into why hackage2 requires so much RAM to run. I will be blogging about that separately. I do expect that we can substantially reduce that amount of RAM it requires. So far I have uncovered two minor issues: 1. it turns out that `mapM Lazy.readFile fileList` returns the file contents lazily but opens all the files immediately. This means you can run out of file descriptors if you have a lot of checkpoints or event files. A patch has been submitted for `acid-state` and it will be fixed in the next release. 2. `acid-state` reads the entire checkpoint file into RAM before decoding it. There are a couple places in the code that cause this to happen. The first place is in `cereal`. The `getLazyByteString` function does return a lazy `ByteString`.. but it does it by first reading a strict `ByteString` of the required length and then converting it into a lazy `ByteString`. Changing the behavior of `getLazyByteString` is actually quite difficult, as `cereal` was designed to allow for value-level error handling, instead of throwing async exceptions. We can probably work around this by using `runGetState` to get one-chunk at a time and build the lazy `ByteString` that way. That might actually be a lot less hackish than it sounds at first, because it allows us to explicity detect and handle failure cases and control how much and when things are read into RAM. Though, at that point, it starts to feel a bit like enumerators/iteratee/etc. Perhaps we will switch to `pipes` at some point in time. `pipes` provides streaming for pure (non-IO) values -- which is probably what we want here. ELM --- Evan Czaplicki has been doing a ton of work on ELM recently. As described on the [ELM Language Homepage](http://elm-lang.org/): "Elm is a type-safe, functional reactive language that compiles to HTML, CSS, and JavaScript." It is easy to use ELM with Happstack -- no special support is required. (i.e., we do not need `happstack-elm`). Vincent Ambo has created a simple demo here: [elm-happstack demo](https://github.com/tazjin/Elm/tree/master/Examples/elm-happstack) web-routes + Hamlet ------------------- Vincent also wrote a nice blog post showing how to combine `web-routes` (type-safe URL routing) with `Hamlet` (a `QuasiQuoter` for generating `blaze-html` from HTML-like syntax): [Best of both worlds: Using Hamlet and web-routes with Happstack](http://tazj.in/en/1335123720) quasi-quoter for language-css ----------------------------- `JMacro` is great for creating JavaScript, but we still have a hole when it comes to generating CSS. The [language-css](http://hackage.haskell.org/package/language-css) library already contains combinators and a syntax ADT for CSS3. If it had a parser, then we could also create a syntax-checking `[css| |]` `QuasiQuoter`. I have discussed the idea with Anton Kholomiov, and he is interested -- but we could use some one else to help write the parser. If you love writing parsers, this should be a fun little project. happstack.com theme ------------------- Finally, if you could suggest one thing that would make the happstack.com website nicer that would be awesome. There are four things we already plan to change: 1. use black on white text instead of gray on white 2. fix the paragraph width so that paragraphs are around 45em wide. 3. fix the grid alignment so that things are properly aligned to the grid 4. add more dates to the pages so that it clear that the site and project is still active If you have other suggestions, we would love to hear them! If you want to hack on the theme directly, that is even better! Until next time, happy hacking. - Jeremy Shaw