Create Search for Google Maps in Opera

So I found the url to use to make Google Maps work as an search engine in Opera:

http://maps.google.com/maps?hl=en&um=1&ie=UTF-8&q=%s&fb=1&gl=us&ct=image&resnum=2

Just right click on the Google Maps search URL and then select "Create Search" but then expand the Details and set the above URL as the address. I also set "m" as the keyword so I just have to type "m New York" in the address bar. Hopefully this will be useful to someone else as well.

Clojure partition-at

While working with some code, I noticed what appears to be a missing function. I wanted to use something like partition-by, which splits the collection each time the passed function returns a new value. Except I wanted it to split whenever the passed function returns true, instead of when the return value changes. Anyways, here it is:

(defn partition-at
  "Like partition-by but will start a new run when f returns true"
  [f coll]
  (lazy-seq
   (when-let [s (seq coll)]
     (let [run (cons (first s) (take-while #(not (f %)) (rest s)))]
       (cons run (partition-at f (drop (count run) s)))))))

Clojure functions need default parameters

So, I have decided to learn the clojure programming language and realized that this was a good place to document the things I learn.

The first thing I found out was that clojure doesn't support default parameters out of the box. So, as step one in learning clojure, I built a new defn that supports default parameters called defo and threw it up on GitHub. It came in useful as I am working my way though the 99 Lisp Problems

Now, instead of writing:

(defn foo
  ([x] (foo x 1))
  ([x y] (foo x y y))
  ([x y z] (+ x y z)))

I can now write:

(defo foo [x (y 1) (z y)] (+ x y z)

Optional parameters are embedded in parenthesis, with the name being followed by what the default value will be.

Apparently recur calls don't roll their args into the final & argument so this causes an error:

(defn go-to-zero [& col]
  (let [f (first col)])
  (if (= 0 f)
    (println "done")
    (recur (dec f))))
(go-to-zero 3)

So there is a part of the macro that would re-write the recur call, placing the final parameters into a list so it doesn't throw errors.

First Post

Yes, I am leaping into the blogging craze. Unfortunatly, I need to get blogspot to work with Opera. I am having to use Firefox to post this. More to come when I can use my default browser...