Subst/AList.thy

small updates because datatype list is now used. In particular Nil -> []

(*  Title: 	Substitutions/alist.thy
    Author: 	Martin Coen, Cambridge University Computer Laboratory
    Copyright   1993  University of Cambridge

Association lists.
*)

AList = List + 

consts

  alist_rec  :: "[('a*'b)list, 'c, ['a, 'b, ('a*'b)list, 'c]=>'c] => 'c"
  assoc      :: "['a,'b,('a*'b) list] => 'b"

rules

  alist_rec_def "alist_rec(al,b,c) == list_rec(b, split(c), al)"

  assoc_def     "assoc(v,d,al) == alist_rec(al,d,%x y xs g.if(v=x,y,g))"

end