Metacadr was broken. You won't believe why!

Lists are mutable, even by-reference.  When I was popping off the values,
I was destroying the list; metacadr only worked once.  That was terrible
functional programming.  I should learn to trust myself; by using a
cons-list for my operations index and a lookup table (anti-if!)
for my operations, the code was simplified incredibly.

Also, added a very (!) primitive pretty printer.  It'll get better over
time, but for now it's sufficient for debugging.

.gitignore

@@ -15,4 +15,5 @@ bin/coffee
 bin/escodegen
 bin/esgenerate
 bin/mocha
+*.js
 

src/lists.coffee

@@ -41,13 +41,13 @@ listToVector = (l, v = []) ->
   listToVector (cdr l), v
 
 metacadr = (m) ->
-  seq = m.match(/c([ad]+)r/)[1].split('')
+  ops = {'a': car, 'd': cdr}
+  seq = vectorToList m.match(/c([ad]+)r/)[1].split('').reverse()
   return (l) ->
     inner = (l, s) ->
-      return nil if nilp l
+      return l if (nilp l) or (nilp s)
-      return l if s.length == 0
+      inner ops[(car s)](l), (cdr s)
-      inner ((if s.pop() == 'a' then car else cdr)(l)), s
+    inner l, seq
-    inner(l, seq)
 
 module.exports =
   cons: cons

src/print.coffee

@@ -0,0 +1,20 @@
+{listToString, listToVector, pairp, cons, car, cdr, caar, cddr, cdar, cadr, caadr, cadar, caddr, nilp, nil, setcdr, metacadr} = require "cons-lists/lists"
+
+evlis = (exps, d) ->
+  if (pairp exps) then evaluate((car exps), d) + " " + evlis((cdr exps), d) else evaluate(exps, d)
+
+indent = (d) ->
+  ([0..d].map () -> " ").join('')
+    
+evaluate = (e, d = 0) ->
+  t = typeof e
+  if (pairp e) then "\n" + indent(d) + "(" + evlis(e, d + 2) + ")"
+  else if (nilp e) then "()"
+  else if t is "boolean" then (if e then "#t" else "#f")
+  else if t is "string"
+    if e.length > 0 and e[0] == '"' then '"' + e + '"' else e
+  else if t is "number" then e
+  else if t is "function" then e.toString()
+  else e.toString()
+    
+module.exports = (c) -> evaluate c, 0