Fields for presentable files can be determined by an application (i) based on a field type and at least one parameter of the fields and (ii) responsive to raw data and a separate transformation engine, even when the application is unaware of the mechanics of the separate transformation engine. In a described implementation for a given field, the field type indicates that the given field is to be evaluated based on raw data that is referenced by the at least one parameter of the given field. The transformation engine is applied to the referenced raw data to produce a result for the given field that is suitable for presentation. In an example implementation, the transformation engine includes multiples sets of presentation rules that may be selectively established for application to the fields. In an example embodiment, respective presentation rule subsets target respective types of raw data.