The fact that millions people before you had travelled to Rome to admire Sistine Chapel shouldn't prevent you from doing the same, right? I thought that implementing the LISP language following the McCarthy's paper Recursive Functions of Symbolic Expressions and Their Computation by Machine may not necessarily make the world a better place, but it'll be certainly a interesting experience. So, here we are.
For now, all the functions are the Java implementations of the functions described in the paper. The unit tests are based on the examples from the paper as well. I tried to make them as faithful as it's possible. This includes the apply - which is actually a LISP interpreter. Javadocs are also copied from the paper.
The apply function can be found in the Evaluator.java class. It's being tested in the EvaluatorTest.java.