Type Inference for Records in a Natural Extension of ML

We describe an extension of ML with records where inheritance is given by ML generic polymorphism. All operations on records introduced by Wand in [Wan87] are supported, in particular the unrestricted extension of a field, and other operations such as renaming of fields are added. The solution relies on both an extension of ML, where the language of types is sorted and considered modulo equations [Rem9Ob], and on a record extension of types [Rem9Oc]. The solution is simple and modular and the type inference algorithm is efficient in practice.