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From 533f2c3b60ef3d3629543045fa308a82ebdcb089 Mon Sep 17 00:00:00 2001 From: Jasper Van der Jeugt Date: Mon, 28 Dec 2009 18:21:03 +0100 Subject: Some more changes for the 0.3 release. --- README.markdown | 215 ++------------------------------------------------------ 1 file changed, 4 insertions(+), 211 deletions(-) (limited to 'README.markdown') diff --git a/README.markdown b/README.markdown index 1b1080d..fbab8ef 100644 --- a/README.markdown +++ b/README.markdown @@ -9,216 +9,9 @@ reference. ## Installation - cabal install hakyll +cabal install hakyll -## Configuration +## Tutorial and information -Inspired by [xmonad](http://xmonad.org), a small Haskell program is used as -configuration file. In this file, you give instructions on how the site should -be generated. In the rest of this document, we will examine a small example. - -This is our directory layout: - - |-- _cache - |-- _site - |-- favicon.ico - |-- hakyll.hs - |-- images - | `-- foo.png - |-- templates - | |-- default.html - | `-- sample.html - `-- text.markdown - -The `_cache` and `_site` directories will be automatically created by hakyll. - -## Static files - -Static files can be rendered using the `static` function. This function -ensures the files will copied when you compile the site. Hakyll is smart enough -to know when files have changed, and will check the modification time of a file -before copying. - -For convenience reasons, there is also a `staticDirectory` function, which works -recursively. - - main = do - static "favicon.ico" - staticDirectory "images" - staticDirectory "css" - -## Pages - -Pages can be written in html, markdown, LaTeX, and basically anything pandoc -supports. They can also contain metadata, which are always key-value mappings. - - --- - author: Jasper Van der Jeugt - title: A sample markdown post - --- - # A sample markdown post - - This is a sample markdown post. It supports pandoc extensions - like code highlighting. For example: - - ~~~~{.haskell} - main = putStrLn "Hello World!" - ~~~~ - -Metadata is always placed in the header of a file, and is delimited by a `---` -string. The metadata can only contain simple key-value pairs. We can now read -in this page using the `Text.Hakyll.Page.readPage` function. This will return a -`Page`, which is actually just a `Map String ByteString`. In this example, the -map would consist of the following key-value pairs: - -- `author`: `Jasper Van der Jeugt` -- `title`: `A sample markdown post` -- `body`: The rest of the file (rendered to html). -- `url`: `text.html` (the original filename was `text.markdown`, the extension - was changed to html). - -## Templates - -In hakyll, there is a strict separation between pages and templates. Templates, -for example, cannot contain metadata. - -

$title

- by $author - - $body - -Templates are rendered using the Haskell `Text.Template` library. This means -that in your template, you can use `$identifier`, and it will be replaced by -the value of `identifier`. - -With this template we could, for example, render the file we saw in the -previous section. It would go like this: - - page <- readPage "text.markdown" - rendered <- render "templates/sample.html" page - writePage rendered - -This reads in `text.markdown`, renders it and writes it to the site destination -(`_site/text.html`). The result of a `render` action is an `IO Page`, the -metadata will be copied from the original page, and the body will be replaced by -the rendering result. This means we can combine rendering actions. Given another -template `templates/default.html`: - - - $title - - - $body - - - -We can now combine the rendering actions (I use `>>=` notation here): - readPage "text.markdown" >>= - render "templates/sample.html" >>= - render "templates/default.html" >>= - writePage - -Jolly good fun and all that, but you can imagine that when we render over nine -thousand posts, our generator will be busy for a while. That's why we have the -`depends` function. It takes a url and a list of dependencies as arguments, and -an IO action. The trick is that this IO action will only be executed if any of -the dependencies is newer than the url given. In our example, we would write: - - depends "text.html" ["text.markdown", "templates/sample.html", "templates/default.html"] - (readPage "text.markdown" >>= render "templates/sample.html" >>= - render "templates/default.html" >>= writePage) - -Not exactly the prettiest code I've ever seen. Because rendering a page with a -number of templates is very common, there's a `renderChain` function to do this -for us. The above can be replaced by - - renderChain ["templates/sample.html", "templates/default.html"] $ - createPagePath "text.markdown" - -The `renderChain` function will automatically check dependencies and write the -page. In fact, it is recommended that you __always__ use this, even when there's -only one template in the chain. - -## More advanced things - -Sometimes, you want to create a `Page` from scratch, without reading from a -file. There are functions to do that for you, and I suggest you read the -documentation of `Text.Hakyll.Page`. As a more advanced example, I will explain -the RSS system I wrote for my website. - - |-- generate.hs - |-- posts - | `-- 2009-12-02-a-first-post.markdown - `-- templates - |-- rss.xml - `-- rssitem.xml - -Our post contains some metadata: - - --- - title: A first post - date: December 2, 2009 - about: A post describing the why and the how of the technical setup of this blog. - --- - - # A first post - - A first post describing the technical setup of this blog, for that is - -The `templates/rssitem.xml` file is a template for rendering one post to an rss -item: - - - $title - http://jaspervdj.be/$url - $about - - -Now a template for rendering the whole rss feed, `templates/rss.xml`: - - - - - jaspervdj - a personal blog - http://jaspervdj.be/ - Personal blog of jaspervdj - $items - - - -Alright, let's get coding. We first want a list of all posts, sorted so the most -recent entries are first in the list. - - postPaths <- liftM (L.reverse . L.sort) $ getRecursiveContents "posts" - -Note that this sorting works because the posts have a -`yyyy-mm-dd-title.extension` naming scheme. We want the paths as `PagePath` and -not as `FilePath` or `String`, because `PagePath` is an instance of -`Renderable`. Also, we only want the 5 most recent posts. - - let renderablePosts = map createPagePath postPaths - let recentItems = renderAndConcat "templates/postitem.html" $ take 5 renderablePosts - -The `renderAndConcat` function takes a template and a list of `Renderable` -items. It renders all renderables with the given template, and concatenates the -result. Note that the concating and reading of pages is not executed yet, -because of laziness. This helps us, since we want to use the modification -timestamps of files, and not render everything every time. - - let rssPage = createCustomPage "rss.xml" - ("templates/rssitem.xml" : postPaths) [("items", Right recentItems)] - -We now created the custom rss page. The `createCustomPage` is a function that -produces a `CustomPage`, which is an instance of `Renderable`. `"rss.xml"` is -our destination url. We then give a list of extra dependencies that were used -to generate the custom page, so Hakyll can check modification stamps. The last -argument is the key-value mapping of our `CustomPage`. Note that the type for -values is `Either String (IO ByteString)`. So, we can either give a simple -string, or an IO action that results in a `ByteString`. The benefit of this is -that the IO action will not be executed if the page in `_site/` is already -up-to-date. Now, we only need to render it using our rss template. - - renderChain ["templates/rss.xml"] rssPage - -That's it. Now we have a rss feed that is generated only when it is not already -up-to-date. +More information can be found on +[the hakyll homepage](http://jaspervdj.be/hakyll). -- cgit v1.2.3