//Wrap the program into a block expression
Expression code = Expression.Block(new ParameterExpression[] { env, voidSingleton}, program);

var asmName = new AssemblyName("Foo");
var asmBuilder = AssemblyBuilder.DefineDynamicAssembly(asmName, AssemblyBuilderAccess.RunAndSave);
var moduleBuilder = asmBuilder.DefineDynamicModule("Foo", "Foo.exe");
var typeBuilder = moduleBuilder.DefineType("Program", TypeAttributes.Public);

var methodBuilder = typeBuilder.DefineMethod("Main",
            MethodAttributes.Static, typeof(void), new[] { typeof(string) });

Expression.Lambda<Action>(code).CompileToMethod(methodBuilder);

typeBuilder.CreateType();
asmBuilder.SetEntryPoint(methodBuilder);
asmBuilder.Save("Foo.exe");