# SRFI 136: Extensible record types

by Marc Nieper-Wißkirchen

status: final (2016/12/25)

## Abstract

SRFI 9 and the compatible R7RS-small provide Scheme with record types. The basic problem that is solved by these record types is that they allow the user to introduce new types, disjoint from all existing types. The record type system described in this document is a conservative extension to SRFI 9 and R7RS record types (in other words, the keyword define-record-type defined in this specification can serve as the equally named keyword from SRFI 9 and R7RS and can thus be safely exported from (srfi 9) and (scheme base)) that is intended to solve another fundamental problem, namely the introduction of subtypes.