Chained comparisons now properly apply DeMorgan's Laws. I couldn't

believe there wasn't a test to remind me to toggle the
{dis,con}junctions. Added that test.

lib/nodes.js

@@ -1485,6 +1485,7 @@
         }
         curr = this;
         while (curr && (curr.operator != null)) {
+          curr.invert = !curr.invert;
           curr.operator = INVERSIONS[curr.operator];
           curr = curr.first;
         }
@@ -1533,7 +1534,7 @@
       if (this.first.unwrap() instanceof Op && this.first.isChainable() && fst.charAt(0) === '(') {
         fst = fst.slice(1, -1);
       }
-      code = "" + fst + " && " + (shared.compile(o)) + " " + this.operator + " " + (this.second.compile(o, LEVEL_OP));
+      code = "" + fst + " " + (this.invert ? '&&' : '||') + " " + (shared.compile(o)) + " " + this.operator + " " + (this.second.compile(o, LEVEL_OP));
       return "(" + code + ")";
     };
     Op.prototype.compileExistence = function(o) {

src/nodes.coffee

@@ -1182,6 +1182,7 @@ exports.Op = class Op extends Base
       return new Parens(this).invert() unless allInvertable
       curr = @
       while curr and curr.operator?
+        curr.invert = !curr.invert
         curr.operator = INVERSIONS[curr.operator]
         curr = curr.first
       this
@@ -1219,7 +1220,7 @@ exports.Op = class Op extends Base
     [@first.second, shared] = @first.second.cache o
     fst = @first.compile o, LEVEL_OP
     fst = fst.slice 1, -1 if @first.unwrap() instanceof Op and @first.isChainable() and fst.charAt(0) is '('
-    code = "#{fst} && #{ shared.compile o } #{@operator} #{ @second.compile o, LEVEL_OP }"
+    code = "#{fst} #{if @invert then '&&' else '||'} #{ shared.compile o } #{@operator} #{ @second.compile o, LEVEL_OP }"
     "(#{code})"
 
   compileExistence: (o) ->

test/test_operations.coffee

@@ -1,6 +1,9 @@
 # CoffeeScript's operations should be chainable, like Python's.
 ok 500 > 50 > 5 > -5
 
+# Some chainable operators can be negated by `unless`
+ok (true unless 0==10!=100)
+
 ok true is not false is true is not false
 
 ok 0 is 0 isnt 50 is 50