iitalics

#lang racket/base
(require redex)

(define-language L
  [x ::= variable-not-otherwise-mentioned]
  [c ::= number null] ; atoms

  [e ::= c (cons e e) x (roll [x] e) (+ e e)] ; expression
  [v ::= c (cons e e)] ; WHNF values
  [e\v ::= (roll [x] e) (+ e e)] ; non-value expressions (thunks?)