to and from basic types (json didn't work)

still not all, but enough for debug experiment to work

lib/ast/expression.rb

@@ -7,25 +7,50 @@
 
 # PS: compare is only for tests and should be factored out to there
 
+Array.class_eval do
+  def to_basic
+    collect do |item|
+      item.to_basic
+    end
+  end
+end
+Symbol.class_eval do
+  def to_basic
+    to_s
+  end
+end
+String.class_eval do
+  def to_basic
+    to_s
+  end
+end
 module Ast
   class Expression
     def attributes
       raise "abstract called for #{self}"
     end
-    def to_json(*a)
-      data = {}
+    def to_basic()
+      data = { "class" => self.class.name }
       attributes.each do |name|
-        data[name] = instance_variable_get(name)
+        val = instance_variable_get("@#{name}".to_sym)
+        res = val.to_basic
+        data[name] = res
       end
-      puts data
-      {
-        "json_class"   => self.class.name,
-        "data"         => data
-      }.to_json(*a)
+      data
     end
 
-    def self.json_create(o)
-      new(*o["data"].values)
+    def self.from_basic(hash)
+      clazz = hash.delete("class")
+      keys = hash.keys
+      klass = clazz.split("::").inject(Object) {|o,c| o.const_get(c)}
+      keys.delete("class")
+      values = keys.collect{|k| read_basic(hash[k]) }
+      klass.new(*values)
+    end
+    def self.read_basic val
+      return from_basic(val) if val.is_a?(Hash)
+      return val.collect{|i| from_basic(i)} if(val.is_a? Array )
+      val
     end
 
     def inspect