dds/bn.rkt
2020-02-15 20:30:46 +01:00

36 lines
1.2 KiB
Racket

#lang typed/racket
;;; dds/bn
;;; This module provides some quick definitions for running Boolean
;;; networks. A Boolean network is a set of Boolean variables which
;;; are updated according to their corresponding update functions.
;;; The variables to be updated at each step are given by the mode.
(provide Variable State UpdateFunc Network
update)
(define-type Variable Symbol)
;;; A state of a Boolean network is a mapping from the variables of the
;;; network to their Boolean values.
(define-type State (HashTable Variable Boolean))
;;; An update function is a Boolean function computing a Boolean value
;;; from the given state.
(define-type UpdateFunc (-> State Boolean))
;;; A Boolean network is a mapping from its variables to its update
;;; functions.
(define-type Network (HashTable Variable UpdateFunc))
;;; Given a state s updates all the variables from xs. This
;;; corresponds to a parallel mode.
(define (update [bn : Network] ; the Boolean network
[s : State] ; the state to operate on
[xs : (Listof Variable)]) ; the variables to update
(let ([new-s : State (hash-copy s)])
(for ([x xs])
(let ([f (hash-ref bn x)])
(hash-set! new-s x (f s))))
new-s))