code: func docsDefinition() (*design.DocsDefinition, bool) {
  	a, ok := dslengine.CurrentDefinition().(*design.DocsDefinition)
  	if !ok {
  		dslengine.IncompatibleDSL()
  	}
  	return a, ok
  }
docs: // docsDefinition returns true and current context if it is a DocsDefinition,
  // nil and false otherwise.