cache the property methods once they're called for the first time

lib/humidifier.rb

@@ -4,6 +4,7 @@
 require 'humidifier/props'
 require 'humidifier/fn'
 require 'humidifier/ref'
+require 'humidifier/property_methods'
 
 require 'humidifier/aws_shim'
 require 'humidifier/resource'

lib/humidifier/property_methods.rb

@@ -0,0 +1,16 @@
+module Humidifier
+  module PropertyMethods
+
+    def build_property_reader(name)
+      define_method(name) do
+        properties[name.to_s]
+      end
+    end
+
+    def build_property_writer(name)
+      define_method(name) do |value|
+        update_property(name.to_s[0..-2], value)
+      end
+    end
+  end
+end

lib/humidifier/resource.rb

@@ -3,6 +3,7 @@ module Humidifier
   # Superclass for all AWS resources
   class Resource
 
+    extend PropertyMethods
     attr_accessor :properties
 
     def initialize(properties = {}, raw = false)
@@ -11,14 +12,14 @@ def initialize(properties = {}, raw = false)
     end
 
     def method_missing(name, *args)
-      sname = name.to_s
-
       if !valid_accessor?(name)
         super
-      elsif self.class.props.key?(sname)
-        properties[sname]
+      elsif self.class.prop?(name.to_s)
+        self.class.build_property_reader(name)
+        send(name)
       else
-        update_property(sname[0..-2], args.first)
+        self.class.build_property_writer(name)
+        send(name, args.first)
       end
     end
 

lib/humidifier/version.rb

@@ -1,3 +1,3 @@
 module Humidifier
-  VERSION = '0.0.15'.freeze
+  VERSION = '0.0.16'.freeze
 end

test/property_methods_test.rb

@@ -0,0 +1,33 @@
+require 'test_helper'
+
+class PropertyMethodsTest < Minitest::Test
+  class Slate
+    extend Humidifier::PropertyMethods
+    attr_accessor :properties
+
+    def initialize(properties = {})
+      self.properties = properties
+    end
+
+    def update_property(key, value)
+      properties[key] = value
+    end
+  end
+
+  def test_build_property_reader
+    Slate.build_property_reader(:foo)
+    slate = Slate.new('foo' => 'bar')
+
+    assert slate.respond_to?(:foo)
+    assert_equal 'bar', slate.foo
+  end
+
+  def test_build_property_writer
+    Slate.build_property_writer(:foo=)
+    slate = Slate.new
+
+    assert slate.respond_to?(:foo=)
+    slate.foo = 'bar'
+    assert_equal 'bar', slate.properties['foo']
+  end
+end