OCamllight in Ott

OCamllight key points •Written in Ott • Faithful to Objective Caml (very nearly) • Type soundness proof mechanized in HOL (Coq and Isabelle/HOL definitions generated too) • Operational semantics validated on test programs • Small-step operational semantics (131 rules) • Type system (179 rules, below) • definitions: – variant data types (e.g., type t = I of int | C of char), – record types (e.g., type t = {f : int; g : bool}), – parametric type constructors (e.g., type ’a t = C of ’a), – type abbreviations (e.g., type ’a t = ’a * int), – mutually recursive combinations of the above (excepting abbreviations), – exceptions, and values; • expressions for type annotations, sequencing, and primitive values (functions, lists, tuples, and records); • with (record update), if, while, for, assert, try, and raise expressions; • let-based polymorphism with an SML-style value restriction; • mutually-recursive function definitions via let rec; • pattern matching, with nested patterns, as patterns, and “or” (|)patterns; • mutable references with ref, !, and :=; • polymorphic equality (the Objective Caml = operator); • 31-bit word semantics for ints (using an existing HOL library); and • IEEE-754 semantics for floats (using an existing HOL library).