Timestamp: #inst “2016-01-26T16:43:00” Title: “Entities” ID: entities


Throughout this documentation & the λ-blog codebase you will run into a somewhat vaguely named concept of entities. An entity is any data structure that represents your content throughout λ-blog generation pipline. For example, the following Clojure map representing a parsed blog entry is an entity:

(def entry {:metadata {:author "Idorobots"
                       :title "Entry title"}
            :contents "<p>Some contents</p>"})

Similarily, your blog configuration can be considered an entity if it happens to contribute to the page generation of another entity:

(def config {:author "Idorobots"
             :stylesheets ["style/style.css"

;; Elswhere in the code:
(->> entry
     (merge config)
     ;; ... process & generate a page

In fact, this is so useful that some of the λ-blog internals will do just that for you automatically, so you don’t have to worry about data duplication when building your generation pipline. This is, however, a topic for another time.

Nested entities

Since λ-blog imposes very few restrictions on entity format, entities can be nested:

(def config {:author "Idorobots"
             :stylesheets ["style/style.css"
             :entries [{:metadata {:title "Entry 1"}
                        :url "www.example.com/entry-1"
                        :contents "<p>Some contents</p>"}
                       {:metadata {:title "Entry 2"}
                        :url "www.example.com/entry-2"
                        :contents "<p>Some other contents</p>"}
                       ; ...

In such a case, :entries can be used as additional metadata while generating some pages of the blog making it easy, for example, to link to more content. Just (map (juxt (comp :title :metadata) :url) entries) to get a list of :title - :url pairs and you’re set.

λ-blog provides many convenient ways to process nested entities & entity internals, but this is, again, a topic for another time.