jackrusher

Hofstadter on Lisp

In the mid-80s, while reading through my roommate's collection of Scientific American back issues, I encountered this introduction to Lisp written by Douglas Hofstadter. I found it very charming at the time, and provide it here (somewhat illegally) for the edification of a new generation of Lispers.

In a testament to the timelessness of Lisp, you can still run all the examples below in emacs if you install these aliases:

(defalias 'plus #'+)
(defalias 'quotient #'/)
(defalias 'times #'*)
(defalias 'difference #'-)

tavisrudd

(defmacro defmethod
  "Creates and installs a new method of multimethod associated with dispatch-value. "
  {:added "1.0"}
  [multifn dispatch-val & fn-tail]
  `(. ~(with-meta multifn {:tag 'clojure.lang.MultiFn}) addMethod ~dispatch-val (fn ~@fn-tail)))

(defmacro defmethod-with-metadata
  "Creates and installs a new method of multimethod associated with dispatch-value. "
  {:added "1.0"}

rippinrobr

;; Here's the program.clj file from a VsClojure project.
;; First thing you need to do is add the :methods property
;; which takes a of methods that are to be generated when
;; the class is created.  Here, I'm generating a static method
;; named hi which has no parameters and returns a String.
;;
;; When program.hi() is called from the C# code the
;; the clojure function -hi will be called.  By default any
;; method in the :methods vector will be mapped to a function
;; with the same name prefixed by a -.