fixing bug in "is" handling

Manifest

@@ -1,4 +1,5 @@
 examples/acls.rb
+examples/hanoi.rb
 History.txt
 lib/ruby-prolog/ruby-prolog.rb
 lib/ruby-prolog.rb

Rakefile

@@ -5,6 +5,6 @@ Echoe.new("ruby-prolog") do |p|
     p.url = "http://www.openrain.com.com"
     # p.docs_host = "uncapitalizer.com:~/www/files/doc/"
     # p.runtime_dependencies = ["string_tools >=1.4.0"]
-    p.version = '0.0.4'
+    p.version = '0.0.5'
     p.email = "preston.lee@openrain.com"
 end

lib/ruby-prolog.rb

@@ -2,7 +2,7 @@
 module RubyProlog
 
   # :stopdoc:
-  VERSION = '0.0.4'
+  VERSION = '0.0.5'
   LIBPATH = ::File.expand_path(::File.dirname(__FILE__)) + ::File::SEPARATOR
   PATH = ::File.dirname(LIBPATH) + ::File::SEPARATOR
   # :startdoc:

lib/ruby-prolog/ruby-prolog.rb

@@ -138,16 +138,17 @@ def [](t)
 
   class CallbackEnvironment
 
-    def initialize(env, trail)
-      @env, @trail = env, trail
+    def initialize(env, trail, core)
+      @env, @trail, @core = env, trail, core
     end
 
     def [](t)
       return @env[t]
     end
 
     def unify(t, u)
-      return _unify(t, @env, u, @env, @trail, @env)
+      # pp "CORE " + @core
+      return @core._unify(t, @env, u, @env, @trail, @env)
     end
 
   end
@@ -233,7 +234,7 @@ def _resolve_body(body, env, cut)
             trail = []
             if _unify_(goal, env, d_head, d_env, trail, d_env)
               if Proc === d_body
-                if d_body[CallbackEnvironment.new(d_env, trail)]
+                if d_body[CallbackEnvironment.new(d_env, trail, self)]
                   _resolve_body(rest, env, cut) {
                     yield
                   }