A Program Inverter for a Functional Language with Equality and Constructors

We present a method for automatic program inversion in a first-order functional programming language. We formalize the transformation and illustrate it with several examples including the automatic derivation of a program for run-length decoding from a program for runlength encoding. This derivation is not possible with other automatic program inversion methods. One of our key observations is that the duplication of values and testing of their equality are two sides of the same coin in program inversion. This leads us to the design of a new self-inverse primitive function that considerably simplifies the automatic inversion of programs.

• Type: Conference
• Year: 2003
• Where: APLAS
• Authors: Robert Glück, Masahiko Kawabe
• Keywords: APLAS 2003, Automatic Derivation, Automatic Program Inversion, Program Inversion Methods