JRuby instance_evals

RubyTest.java

import org.jruby.embed.ScriptingContainer;


public class RubyTest {
    public static void main(String[] args) {
        ScriptingContainer container = new ScriptingContainer();

        // From a string
        Object myclassString = container.runScriptlet("" +
                "class MyClass\n" +
                "  def parse_stuff(body)\n" +
                "    instance_eval(body)\n" +
                "  end\n" +
                "end\n" +
                "MyClass.new");
        container.callMethod(myclassString, "parse_stuff",
                "Kernel.eval 'def abc() ::Kernel.puts 123 end'\n" +
                "abc");

    }
}

/*
Output:

NameError: undefined local variable or method `abc' for #<MyClass:0x7bac686b>
         <eval> at (eval):2
*/

In irb...

irb(main):009:0> class MyClass
irb(main):010:1>  def parse_stuff(body)
irb(main):011:2>   instance_eval(body)
irb(main):012:2>   end
irb(main):013:1> end
=> nil
irb(main):014:0> m = MyClass.new
=> #<MyClass:0x007ff293903688>
irb(main):015:0> m.parse_stuff("::Kernel.eval('def foo; ::Kernel.puts 2; end');foo")
2
=> nil
irb(main):016:0>