support instance variables from block context in one-level dsl

lib/docile.rb

@@ -18,7 +18,13 @@ module Docile
   # @return [Object]     the given DSL object
   def dsl_eval(dsl, &block)
     block_context = eval("self", block.binding)
-    FallbackContextProxy.new(dsl, block_context).instance_eval(&block)
+    proxy_context = FallbackContextProxy.new(dsl, block_context)
+    block_context.instance_variables.each { |ivar| proxy_context.instance_variable_set(ivar, block_context.instance_variable_get(ivar)) }
+    begin
+      proxy_context.instance_eval(&block)
+    ensure
+      block_context.instance_variables.each { |ivar| block_context.instance_variable_set(ivar, proxy_context.instance_variable_get(ivar)) }
+    end
     dsl
   end
   module_function :dsl_eval

lib/docile/fallback_context_proxy.rb

@@ -2,7 +2,9 @@ require 'set'
 
 module Docile
   class FallbackContextProxy
-    BASIC_METHODS = Set[:==, :equal?, :"!", :"!=", :instance_eval, :object_id, :__send__, :__id__]
+    BASIC_METHODS = Set[:==, :equal?, :"!", :"!=",
+                        :instance_eval, :instance_variable_get, :instance_variable_set,
+                        :object_id, :__send__, :__id__]
 
     instance_methods.each do |method|
       unless BASIC_METHODS.include?(method.to_sym)

spec/docile_spec.rb

@@ -72,8 +72,14 @@ describe Docile do
     end
 
     context "instance variables" do
+      it "should find instance variable from block definition in outer dsl scope" do
+        @iv1 = 'iv1'; outer { @iv1.should == 'iv1' }
+      end
+
       #it "should find instance variable from block definition in inner dsl scope" do
-      #  @iv1 = 'iv1'; outer { inner { @iv1.should == 'iv1' } }
+      #  @iv2 = 'iv2'; outer { inner {
+      #    @iv2.should == 'iv2'
+      #  } }
       #end
     end