Brad Lucas

Programming, Clojure and other interests

Bradlucas.Com

November 6, 2012

Getting back to things and have updated my personal page at http://bradlucas.com.

It is a simple page with six thumbnails using Twitter Bootstrap (http://twitter.github.com/bootstrap/). What made it nice is that it is responsive so it works well on any device.


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Building Command Line Applications With Clojure

March 9, 2012

To be able to package your Clojure application as a single jar and to run it from a script or the command line is a very handy thing. At first it might not be all that apparent how to do this if you are staring to learn Clojure and are happily hacking away in the Repl or evaluating code from Emacs using Slime. But, it is possible and very easy to do. You'll need to be using Leiningen so at this point I'll assume you are.

Java and One-JAR

Back in the day when you wanted to deliver your Java application you had to collect all the dependent Jar files and your own Jar or class files and then come up with a script to kick the whole thing off. You had to make sure things were all in the right place and your Classpath was correct.


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Loading Data With Clojure

March 4, 2012

If you are coming to Clojure from Java you are probably familiar with JDBC. If not do a bit of research and you'll find that it is a layer that allows you to program against a database agnostic layer that communicates to your database through a database specific library. In the following example we'll use the clojure.java.jdbc wrapper for JDBC-based access to databases. This library is not part of what you would automatically have when you just install Clojure. For use to use it we'll have to download it ourselves or use a build tool to do it for us. To keep things simple here I'll assume you are using Leiningen as a build tool. If not you can find clojure.java.jdbc on GitHub. Also, you will have to have a database. Here I'll assume MySQL and explain how to connect to that. The example we'll build here will be an enhancement to the stock quote downloader presented in Reading Files article. Instead of writing the quotes to a file we'll load them into a database. You might want to review the article before continuing.

Database

Here we'll use MySQL but you could be using another. The only difference in the following will be the setting up of your database's JDBC library.

Install and Setup JDBC Driver


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Writing Files In Clojure

March 2, 2012

In the previous post we saw how to read files and then introduced a function to write them. The example presented downloaded stock quotes from Yahoo and then writes the data to a local file. Let's look a bit more into writing to files in Clojure.

Writing Short Strings

The opposite of slurp is spit. This is for writing short strings to files. You call the function with the name of the file and the string.

user=> (spit "testfile.txt" "This is my string")

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Yahoo Quote Downloader In Clojure

February 26, 2012

Yahoo provides downloadable historical quote data if you exercise a properly formatted URL. The data is returned in CSV format and is easily stored in a file. I wrote quote-downloader to accept stock symbols from the command line and request and store the data in symbol.csv files locally.

The program demonstrates reading from the command line, building a unique URL and reading from it as well as saving the results to a file and

The code is on github here https://github.com/bradlucas/quote-downloader


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