Add ruby

examples/ruby/classes.rb

@@ -0,0 +1,52 @@
+# Class names must be capitalized.  Technically, it's a constant.
+class Fred
+
+  # The initialize method is the constructor.  The @val is
+  # an object value.
+  def initialize(v)
+    @val = v
+  end
+
+  # Set it and get it.
+  def set(v)
+    @val = v
+  end
+
+  def get
+    return @val
+  end
+end
+
+# Objects are created by the new method of the class object.
+a = Fred.new(10)
+b = Fred.new(22)
+
+print "A: ", a.get, " ", b.get,"\n";
+b.set(34)
+print "B: ", a.get, " ", b.get,"\n";
+
+# Ruby classes are always unfinished works.  This does not
+# re-define Fred, it adds more stuff to it.
+class Fred 
+  def inc
+    @val += 1
+  end
+end
+
+a.inc
+b.inc
+print "C: ", a.get, " ", b.get,"\n";
+
+# Objects may have methods all to themselves.
+def b.dec
+  @val -= 1
+end
+
+begin
+  b.dec
+  a.dec
+rescue StandardError => msg
+  print "Error: ", msg, "\n"
+end
+
+print "D: ", a.get, " ", b.get,"\n";