diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..c2cbb17
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,14 @@
+/target
+/lib
+/classes
+/checkouts
+pom.xml
+pom.xml.asc
+*.jar
+*.class
+.lein-deps-sum
+.lein-failures
+.lein-plugins
+.lein-repl-history
+
+.nrepl-port
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..48bb140
--- /dev/null
+++ b/README.md
@@ -0,0 +1,13 @@
+# abc
+
+A Clojure library designed to ... well, that part is up to you.
+
+## Usage
+
+FIXME
+
+## License
+
+Copyright © 2014 FIXME
+
+Distributed under the Eclipse Public License, the same as Clojure.
diff --git a/doc/intro.md b/doc/intro.md
new file mode 100644
index 0000000..0edf1a7
--- /dev/null
+++ b/doc/intro.md
@@ -0,0 +1,3 @@
+# Introduction to abc
+
+TODO: write [great documentation](http://jacobian.org/writing/great-documentation/what-to-write/)
diff --git a/project.clj b/project.clj
new file mode 100644
index 0000000..407bf16
--- /dev/null
+++ b/project.clj
@@ -0,0 +1,7 @@
+(defproject abc "0.1.0-SNAPSHOT"
+  :description "FIXME: write description"
+  :url "http://example.com/FIXME"
+  :license {:name "Eclipse Public License"
+            :url "http://www.eclipse.org/legal/epl-v10.html"}
+  :dependencies [[org.clojure/clojure "1.5.1"]
+                 [org.jruby/jrubyparser "0.5.3"]])
diff --git a/src/abc/core.clj b/src/abc/core.clj
new file mode 100644
index 0000000..b85c071
--- /dev/null
+++ b/src/abc/core.clj
@@ -0,0 +1,11 @@
+(ns abc.core)
+
+(defn metric-result [rs]
+  (fn [metric]
+    (let [metric-result (get-in rs [:metrics metric] 0)]
+      (* metric-result metric-result))))
+
+(defn abc [rs]
+  (Math/sqrt (apply +
+                    (map (metric-result rs)
+                         [:branches :assignments :conditionals]))))
diff --git a/src/abc/extractors/ruby.clj b/src/abc/extractors/ruby.clj
new file mode 100644
index 0000000..9942abb
--- /dev/null
+++ b/src/abc/extractors/ruby.clj
@@ -0,0 +1,69 @@
+(ns abc.extractors.ruby
+    (:import (org.jrubyparser Parser CompatVersion)
+           (org.jrubyparser.parser ParserConfiguration)
+           (java.io StringReader)))
+
+(defn parse-ruby [rb]
+  (let [parser (Parser.)
+        config (ParserConfiguration. 0 CompatVersion/RUBY1_9)]
+    (.parse parser "" (StringReader. rb) config)))
+
+(defn- children? [_] true)
+(defn- children [n]
+  (.childNodes n))
+(defn- make-tree [root]
+  (tree-seq children? children root))
+
+(defn- defn-node? [n]
+  (instance? org.jrubyparser.ast.DefnNode n))
+(defn- assignment-node? [n]
+  (instance? org.jrubyparser.ast.LocalAsgnNode n))
+(defn- conditional-node? [n]
+  (instance? org.jrubyparser.ast.IfNode n))
+(defn- branch-node? [n]
+  (instance? org.jrubyparser.ast.FCallNode n))
+
+(defn- filter-nodes [root f]
+  (loop [tree root]
+    (cond (empty? tree) '()
+          (f (first tree)) (cons (first tree) (filter-nodes (rest tree) f))
+          (seq? (first tree)) (concat (filter-nodes (first tree) f)
+                                      (filter-nodes (rest tree) f))
+          :else (recur (rest tree)))))
+
+(defn- line-number [n]
+  (inc (.. n getPosition getEndLine)))
+
+(defn- line-range [n]
+  (let [source-position (.getPosition n)]
+    [(.getStartOffset source-position)
+     (.getEndOffset source-position)]))
+
+(defn- extract [f]
+  (fn [root]
+    (let [nodes (filter-nodes (make-tree root) f)]
+      (when-not (empty? nodes)
+        (map (fn [n]
+               {:line (line-number n) :range (line-range n)})
+             nodes)))))
+
+(defn- ruby-source [rb [start end]]
+  (apply str (take (- end start) (drop start rb))))
+
+(defn- with-source [rb & fks]
+  (fn [root]
+    (reduce (fn [e [f k]]
+              (assoc e k
+                (map (fn [env]
+                       (assoc env :source (ruby-source rb (:range env))))
+                     ((extract f) root))))
+            {}
+            fks)))
+
+(defn parse [rb]
+  (let [root (parse-ruby rb)
+        defn-nodes (filter-nodes (make-tree root) defn-node?)]
+    (map (with-source rb [assignment-node? :assignments]
+                         [conditional-node? :conditionals]
+                         [branch-node? :branches])
+         defn-nodes)))
diff --git a/test/abc/core_test.clj b/test/abc/core_test.clj
new file mode 100644
index 0000000..0731f0f
--- /dev/null
+++ b/test/abc/core_test.clj
@@ -0,0 +1,10 @@
+(ns abc.core-test
+  (:require [clojure.test :refer :all]
+            [abc.core :refer :all]))
+
+(deftest abc-test
+  (testing "metric"
+    (is (= (abc {:method "foo" :metrics {:conditionals 2
+                                          :branches 5
+                                          :assignments 10}}))
+           11)))
diff --git a/test/abc/extractors/ruby_test.clj b/test/abc/extractors/ruby_test.clj
new file mode 100644
index 0000000..ceb184d
--- /dev/null
+++ b/test/abc/extractors/ruby_test.clj
@@ -0,0 +1,23 @@
+(ns abc.extractors.ruby-test
+  (:require [clojure.test :refer :all]
+            [abc.extractors.ruby :refer :all]))
+
+(def ruby
+"def foo
+  bar = 3
+  wat if condition
+  method_call()
+end")
+
+(deftest ruby-extractor-test
+  (testing "assignment"
+    (is (= [{:line 2 :range [10 17] :source "bar = 3"}]
+           (:assignments (first (parse ruby))))))
+
+  (testing "conditional"
+    (is (= [{:line 3 :range [20 36] :source "wat if condition"}]
+           (:conditionals (first (parse ruby))))))
+
+  (testing "branching"
+    (is (= [{:line 4 :range [39 52] :source "method_call()"}]
+           (:branches (first (parse ruby)))))))