diff -r f04b33ce250f -r a4dc62a46ee4 ex/Term.ML --- a/ex/Term.ML Tue Oct 24 14:59:17 1995 +0100 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,165 +0,0 @@ -(* Title: HOL/ex/Term - ID: $Id$ - Author: Lawrence C Paulson, Cambridge University Computer Laboratory - Copyright 1992 University of Cambridge - -Terms over a given alphabet -- function applications; illustrates list functor - (essentially the same type as in Trees & Forests) -*) - -open Term; - -(*** Monotonicity and unfolding of the function ***) - -goal Term.thy "term(A) = A <*> list(term(A))"; -by (fast_tac (univ_cs addSIs (equalityI :: term.intrs) - addEs [term.elim]) 1); -qed "term_unfold"; - -(*This justifies using term in other recursive type definitions*) -goalw Term.thy term.defs "!!A B. A<=B ==> term(A) <= term(B)"; -by (REPEAT (ares_tac ([lfp_mono, list_mono] @ basic_monos) 1)); -qed "term_mono"; - -(** Type checking -- term creates well-founded sets **) - -goalw Term.thy term.defs "term(sexp) <= sexp"; -by (rtac lfp_lowerbound 1); -by (fast_tac (univ_cs addIs [sexp.SconsI, list_sexp RS subsetD]) 1); -qed "term_sexp"; - -(* A <= sexp ==> term(A) <= sexp *) -bind_thm ("term_subset_sexp", ([term_mono, term_sexp] MRS subset_trans)); - - -(** Elimination -- structural induction on the set term(A) **) - -(*Induction for the set term(A) *) -val [major,minor] = goal Term.thy - "[| M: term(A); \ -\ !!x zs. [| x: A; zs: list(term(A)); zs: list({x.R(x)}) \ -\ |] ==> R(x$zs) \ -\ |] ==> R(M)"; -by (rtac (major RS term.induct) 1); -by (REPEAT (eresolve_tac ([minor] @ - ([Int_lower1,Int_lower2] RL [list_mono RS subsetD])) 1)); -(*Proof could also use mono_Int RS subsetD RS IntE *) -qed "Term_induct"; - -(*Induction on term(A) followed by induction on list *) -val major::prems = goal Term.thy - "[| M: term(A); \ -\ !!x. [| x: A |] ==> R(x$NIL); \ -\ !!x z zs. [| x: A; z: term(A); zs: list(term(A)); R(x$zs) \ -\ |] ==> R(x $ CONS(z,zs)) \ -\ |] ==> R(M)"; -by (rtac (major RS Term_induct) 1); -by (etac list.induct 1); -by (REPEAT (ares_tac prems 1)); -qed "Term_induct2"; - -(*** Structural Induction on the abstract type 'a term ***) - -val list_all_ss = map_ss addsimps [list_all_Nil, list_all_Cons]; - -val Rep_term_in_sexp = - Rep_term RS (range_Leaf_subset_sexp RS term_subset_sexp RS subsetD); - -(*Induction for the abstract type 'a term*) -val prems = goalw Term.thy [App_def,Rep_Tlist_def,Abs_Tlist_def] - "[| !!x ts. list_all(R,ts) ==> R(App(x,ts)) \ -\ |] ==> R(t)"; -by (rtac (Rep_term_inverse RS subst) 1); (*types force good instantiation*) -by (res_inst_tac [("P","Rep_term(t) : sexp")] conjunct2 1); -by (rtac (Rep_term RS Term_induct) 1); -by (REPEAT (ares_tac [conjI, sexp.SconsI, term_subset_sexp RS - list_subset_sexp, range_Leaf_subset_sexp] 1 - ORELSE etac rev_subsetD 1)); -by (eres_inst_tac [("A1","term(?u)"), ("f1","Rep_term"), ("g1","Abs_term")] - (Abs_map_inverse RS subst) 1); -by (rtac (range_Leaf_subset_sexp RS term_subset_sexp) 1); -by (etac Abs_term_inverse 1); -by (etac rangeE 1); -by (hyp_subst_tac 1); -by (resolve_tac prems 1); -by (etac list.induct 1); -by (etac CollectE 2); -by (stac Abs_map_CONS 2); -by (etac conjunct1 2); -by (etac rev_subsetD 2); -by (rtac list_subset_sexp 2); -by (fast_tac set_cs 2); -by (ALLGOALS (asm_simp_tac list_all_ss)); -qed "term_induct"; - -(*Induction for the abstract type 'a term*) -val prems = goal Term.thy - "[| !!x. R(App(x,Nil)); \ -\ !!x t ts. R(App(x,ts)) ==> R(App(x, t#ts)) \ -\ |] ==> R(t)"; -by (rtac term_induct 1); (*types force good instantiation*) -by (etac rev_mp 1); -by (rtac list_induct 1); (*types force good instantiation*) -by (ALLGOALS (asm_simp_tac (list_all_ss addsimps prems))); -qed "term_induct2"; - -(*Perform induction on xs. *) -fun term_ind2_tac a i = - EVERY [res_inst_tac [("t",a)] term_induct2 i, - rename_last_tac a ["1","s"] (i+1)]; - - - -(*** Term_rec -- by wf recursion on pred_sexp ***) - -val Term_rec_unfold = - wf_pred_sexp RS wf_trancl RS (Term_rec_def RS def_wfrec); - -(** conversion rules **) - -val [prem] = goal Term.thy - "N: list(term(A)) ==> \ -\ !M. : pred_sexp^+ --> \ -\ Abs_map(cut(h, pred_sexp^+, M), N) = \ -\ Abs_map(h,N)"; -by (rtac (prem RS list.induct) 1); -by (simp_tac list_all_ss 1); -by (strip_tac 1); -by (etac (pred_sexp_CONS_D RS conjE) 1); -by (asm_simp_tac (list_all_ss addsimps [trancl_pred_sexpD1, cut_apply]) 1); -qed "Abs_map_lemma"; - -val [prem1,prem2,A_subset_sexp] = goal Term.thy - "[| M: sexp; N: list(term(A)); A<=sexp |] ==> \ -\ Term_rec(M$N, d) = d(M, N, Abs_map(%Z. Term_rec(Z,d), N))"; -by (rtac (Term_rec_unfold RS trans) 1); -by (simp_tac (HOL_ss addsimps - [Split, - prem2 RS Abs_map_lemma RS spec RS mp, pred_sexpI2 RS r_into_trancl, - prem1, prem2 RS rev_subsetD, list_subset_sexp, - term_subset_sexp, A_subset_sexp])1); -qed "Term_rec"; - -(*** term_rec -- by Term_rec ***) - -local - val Rep_map_type1 = read_instantiate_sg (sign_of Term.thy) - [("f","Rep_term")] Rep_map_type; - val Rep_Tlist = Rep_term RS Rep_map_type1; - val Rep_Term_rec = range_Leaf_subset_sexp RSN (2,Rep_Tlist RSN(2,Term_rec)); - - (*Now avoids conditional rewriting with the premise N: list(term(A)), - since A will be uninstantiated and will cause rewriting to fail. *) - val term_rec_ss = HOL_ss - addsimps [Rep_Tlist RS (rangeI RS term.APP_I RS Abs_term_inverse), - Rep_term_in_sexp, Rep_Term_rec, Rep_term_inverse, - inj_Leaf, Inv_f_f, - Abs_Rep_map, map_ident, sexp.LeafI] -in - -val term_rec = prove_goalw Term.thy - [term_rec_def, App_def, Rep_Tlist_def, Abs_Tlist_def] - "term_rec(App(f,ts), d) = d(f, ts, map (%t. term_rec(t,d), ts))" - (fn _ => [simp_tac term_rec_ss 1]) - -end;