Book Image

Clojure for Domain-specific Languages

By : Ryan D. Kelker
Book Image

Clojure for Domain-specific Languages

By: Ryan D. Kelker

Overview of this book

<p>Clojure is a very new and rapidly growing language that runs on top of the JVM. The language being hosted on the Java platform allows for Clojure applications to use existing Java components. Although there are objects in Clojure, the language is not object oriented.</p> <p>"Clojure for Domain-specific Languages" is an example-oriented guide to building custom languages. Many of the core components of Clojure are covered to help you understand your options when making a domain-specific language. By the end of this book, you should be able to make an internal DSL. Starting with a comparison of existing DSLs, this book will move on to guide you through general programming, Clojure editing, and project management. The chapters after that are code oriented.</p> <p>"Clojure for Domain-specific Languages" tries to expose you to as much Clojure code as possible. Many of the examples are executed in a Read-Evaluate-Print-Loop environment, so the reader can also follow along on their own machine. This book uses Leiningen, but no prior knowledge of it is required.</p> <p>"Clojure for Domain-Specific Languages" aims to make you familiar with the Clojure language and help you learn the tools to make your own language.</p>
Table of Contents (19 chapters)
Clojure for Domain-specific Languages
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Handling search queries


For brevity, this section will only cover retrieving the username, screen name, date, and text of the search results. Please refer to the documentation of the twitter4j library for more information. The documentation page for the QueryResult class is located at http://twitter4j.org/oldjavadocs/3.0.3/twitter4j/QueryResult.html.

Adding the tdsl.search namespace

The search capabilities should go in their own namespace, so you'll need to create a new file at tdsl/src/tdsl/search.clj. The namespace of this file should use two dynamic variables from the tdsl.core namespace, namely *twitter* and *tweets*. The namespace also needs to import the Query class from the twitter4j Java library. If done correctly, the beginning of the file should be similar to the REPL session shown as follows:

tdsl.core> (ns tdsl.search
            (:use [tdsl.core
                   :only [*twitter*
                          *tweets*]])
            (:import [twitter4j Query]))
nil
tdsl.search...