src/ZF/ex/Term.thy
author clasohm
Tue Feb 06 12:27:17 1996 +0100 (1996-02-06)
changeset 1478 2b8c2a7547ab
parent 1401 0c439768f45c
child 3840 e0baea4d485a
permissions -rw-r--r--
expanded tabs
     1 (*  Title:      ZF/ex/Term.thy
     2     ID:         $Id$
     3     Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
     4     Copyright   1994  University of Cambridge
     5 
     6 Terms over an alphabet.
     7 Illustrates the list functor (essentially the same type as in Trees & Forests)
     8 *)
     9 
    10 Term = List +
    11 consts
    12   term_rec  :: [i, [i,i,i]=>i] => i
    13   term_map  :: [i=>i, i] => i
    14   term_size :: i=>i
    15   reflect   :: i=>i
    16   preorder  :: i=>i
    17 
    18   term      :: i=>i
    19 
    20 datatype
    21   "term(A)" = Apply ("a: A", "l: list(term(A))")
    22   monos       "[list_mono]"
    23 
    24   type_elims  "[make_elim (list_univ RS subsetD)]"
    25 (*Or could have
    26     type_intrs  "[list_univ RS subsetD]"
    27 *)
    28 
    29 defs
    30   term_rec_def
    31    "term_rec(t,d) == 
    32    Vrec(t, %t g. term_case(%x zs. d(x, zs, map(%z.g`z, zs)), t))"
    33 
    34   term_map_def  "term_map(f,t) == term_rec(t, %x zs rs. Apply(f(x), rs))"
    35 
    36   term_size_def "term_size(t) == term_rec(t, %x zs rs. succ(list_add(rs)))"
    37 
    38   reflect_def   "reflect(t) == term_rec(t, %x zs rs. Apply(x, rev(rs)))"
    39 
    40   preorder_def  "preorder(t) == term_rec(t, %x zs rs. Cons(x, flat(rs)))"
    41 
    42 end