author  oheimb 
Wed, 18 Dec 1996 15:12:34 +0100  
changeset 2443  a81d4c219c3c 
parent 2263  c741309167bf 
child 2595  548f8ed89a80 
permissions  rwrr 
1465  1 
(* Title: HOL/simpdata.ML 
923  2 
ID: $Id$ 
1465  3 
Author: Tobias Nipkow 
923  4 
Copyright 1991 University of Cambridge 
5 

6 
Instantiation of the generic simplifier 

7 
*) 

8 

1984  9 
section "Simplifier"; 
10 

923  11 
open Simplifier; 
12 

1922  13 
(*** Integration of simplifier with classical reasoner ***) 
14 

15 
(*Add a simpset to a classical set!*) 

16 
infix 4 addss; 

17 
fun cs addss ss = cs addbefore asm_full_simp_tac ss 1; 

18 

19 
fun Addss ss = (claset := !claset addbefore asm_full_simp_tac ss 1); 

20 

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21 
(*Designed to be idempotent, except if best_tac instantiates variables 
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22 
in some of the subgoals*) 
1922  23 
fun auto_tac (cs,ss) = 
24 
ALLGOALS (asm_full_simp_tac ss) THEN 

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25 
REPEAT (safe_tac cs THEN ALLGOALS (asm_full_simp_tac ss)) THEN 
2036  26 
REPEAT (FIRSTGOAL (best_tac (cs addss ss))) THEN 
27 
prune_params_tac; 

1922  28 

29 
fun Auto_tac() = auto_tac (!claset, !simpset); 

30 

31 
fun auto() = by (Auto_tac()); 

32 

33 

1984  34 
(*** Addition of rules to simpsets and clasets simultaneously ***) 
35 

36 
(*Takes UNCONDITIONAL theorems of the form A<>B to 

2031  37 
the Safe Intr rule B==>A and 
38 
the Safe Destruct rule A==>B. 

1984  39 
Also ~A goes to the Safe Elim rule A ==> ?R 
40 
Failing other cases, A is added as a Safe Intr rule*) 

41 
local 

42 
val iff_const = HOLogic.eq_const HOLogic.boolT; 

43 

44 
fun addIff th = 

45 
(case HOLogic.dest_Trueprop (#prop(rep_thm th)) of 

2031  46 
(Const("not",_) $ A) => 
47 
AddSEs [zero_var_indexes (th RS notE)] 

48 
 (con $ _ $ _) => 

49 
if con=iff_const 

50 
then (AddSIs [zero_var_indexes (th RS iffD2)]; 

51 
AddSDs [zero_var_indexes (th RS iffD1)]) 

52 
else AddSIs [th] 

53 
 _ => AddSIs [th]; 

1984  54 
Addsimps [th]) 
55 
handle _ => error ("AddIffs: theorem must be unconditional\n" ^ 

2031  56 
string_of_thm th) 
1984  57 

58 
fun delIff th = 

59 
(case HOLogic.dest_Trueprop (#prop(rep_thm th)) of 

2031  60 
(Const("not",_) $ A) => 
61 
Delrules [zero_var_indexes (th RS notE)] 

62 
 (con $ _ $ _) => 

63 
if con=iff_const 

64 
then Delrules [zero_var_indexes (th RS iffD2), 

65 
zero_var_indexes (th RS iffD1)] 

66 
else Delrules [th] 

67 
 _ => Delrules [th]; 

1984  68 
Delsimps [th]) 
69 
handle _ => warning("DelIffs: ignoring conditional theorem\n" ^ 

2031  70 
string_of_thm th) 
1984  71 
in 
72 
val AddIffs = seq addIff 

73 
val DelIffs = seq delIff 

74 
end; 

75 

76 

923  77 
local 
78 

1922  79 
fun prover s = prove_goal HOL.thy s (fn _ => [fast_tac HOL_cs 1]); 
923  80 

1922  81 
val P_imp_P_iff_True = prover "P > (P = True)" RS mp; 
82 
val P_imp_P_eq_True = P_imp_P_iff_True RS eq_reflection; 

923  83 

1922  84 
val not_P_imp_P_iff_F = prover "~P > (P = False)" RS mp; 
85 
val not_P_imp_P_eq_False = not_P_imp_P_iff_F RS eq_reflection; 

923  86 

1922  87 
fun atomize pairs = 
88 
let fun atoms th = 

2031  89 
(case concl_of th of 
90 
Const("Trueprop",_) $ p => 

91 
(case head_of p of 

92 
Const(a,_) => 

93 
(case assoc(pairs,a) of 

94 
Some(rls) => flat (map atoms ([th] RL rls)) 

95 
 None => [th]) 

96 
 _ => [th]) 

97 
 _ => [th]) 

1922  98 
in atoms end; 
923  99 

2134  100 
fun gen_all th = forall_elim_vars (#maxidx(rep_thm th)+1) th; 
101 

102 
in 

103 

1922  104 
fun mk_meta_eq r = case concl_of r of 
2031  105 
Const("==",_)$_$_ => r 
1922  106 
 _$(Const("op =",_)$_$_) => r RS eq_reflection 
107 
 _$(Const("not",_)$_) => r RS not_P_imp_P_eq_False 

108 
 _ => r RS P_imp_P_eq_True; 

109 
(* last 2 lines requires all formulae to be of the from Trueprop(.) *) 

923  110 

2082  111 
val simp_thms = map prover 
112 
[ "(x=x) = True", 

113 
"(~True) = False", "(~False) = True", "(~ ~ P) = P", 

114 
"(~P) ~= P", "P ~= (~P)", "(P ~= Q) = (P = (~Q))", 

115 
"(True=P) = P", "(P=True) = P", 

116 
"(True > P) = P", "(False > P) = True", 

117 
"(P > True) = True", "(P > P) = True", 

118 
"(P > False) = (~P)", "(P > ~P) = (~P)", 

119 
"(P & True) = P", "(True & P) = P", 

120 
"(P & False) = False", "(False & P) = False", "(P & P) = P", 

121 
"(P  True) = True", "(True  P) = True", 

122 
"(P  False) = P", "(False  P) = P", "(P  P) = P", 

123 
"((~P) = (~Q)) = (P=Q)", 

2129  124 
"(!x.P) = P", "(? x.P) = P", "? x. x=t", "? x. t=x", 
2082  125 
"(? x. x=t & P(x)) = P(t)", "(? x. t=x & P(x)) = P(t)", 
126 
"(! x. x=t > P(x)) = P(t)", "(! x. t=x > P(x)) = P(t)" ]; 

923  127 

988  128 
(*Add congruence rules for = (instead of ==) *) 
129 
infix 4 addcongs; 

923  130 
fun ss addcongs congs = ss addeqcongs (congs RL [eq_reflection]); 
131 

1264  132 
fun Addcongs congs = (simpset := !simpset addcongs congs); 
133 

923  134 
fun mksimps pairs = map mk_meta_eq o atomize pairs o gen_all; 
135 

1922  136 
val imp_cong = impI RSN 
137 
(2, prove_goal HOL.thy "(P=P')> (P'> (Q=Q'))> ((P>Q) = (P'>Q'))" 

138 
(fn _=> [fast_tac HOL_cs 1]) RS mp RS mp); 

139 

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(*Miniscoping: pushing in existential quantifiers*) 
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141 
val ex_simps = map prover 
2031  142 
["(EX x. P x & Q) = ((EX x.P x) & Q)", 
143 
"(EX x. P & Q x) = (P & (EX x.Q x))", 

144 
"(EX x. P x  Q) = ((EX x.P x)  Q)", 

145 
"(EX x. P  Q x) = (P  (EX x.Q x))", 

146 
"(EX x. P x > Q) = ((ALL x.P x) > Q)", 

147 
"(EX x. P > Q x) = (P > (EX x.Q x))"]; 

1948
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148 

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(*Miniscoping: pushing in universal quantifiers*) 
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150 
val all_simps = map prover 
2031  151 
["(ALL x. P x & Q) = ((ALL x.P x) & Q)", 
152 
"(ALL x. P & Q x) = (P & (ALL x.Q x))", 

153 
"(ALL x. P x  Q) = ((ALL x.P x)  Q)", 

154 
"(ALL x. P  Q x) = (P  (ALL x.Q x))", 

155 
"(ALL x. P x > Q) = ((EX x.P x) > Q)", 

156 
"(ALL x. P > Q x) = (P > (ALL x.Q x))"]; 

1948
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Added miniscoping to the simplifier: quantifiers are now pushed in
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157 

1722  158 

923  159 

2022  160 
(* elimination of existential quantifiers in assumptions *) 
923  161 

162 
val ex_all_equiv = 

163 
let val lemma1 = prove_goal HOL.thy 

164 
"(? x. P(x) ==> PROP Q) ==> (!!x. P(x) ==> PROP Q)" 

165 
(fn prems => [resolve_tac prems 1, etac exI 1]); 

166 
val lemma2 = prove_goalw HOL.thy [Ex_def] 

167 
"(!!x. P(x) ==> PROP Q) ==> (? x. P(x) ==> PROP Q)" 

168 
(fn prems => [REPEAT(resolve_tac prems 1)]) 

169 
in equal_intr lemma1 lemma2 end; 

170 

171 
end; 

172 

173 
fun prove nm thm = qed_goal nm HOL.thy thm (fn _ => [fast_tac HOL_cs 1]); 

174 

175 
prove "conj_commute" "(P&Q) = (Q&P)"; 

176 
prove "conj_left_commute" "(P&(Q&R)) = (Q&(P&R))"; 

177 
val conj_comms = [conj_commute, conj_left_commute]; 

2134  178 
prove "conj_assoc" "((P&Q)&R) = (P&(Q&R))"; 
923  179 

1922  180 
prove "disj_commute" "(PQ) = (QP)"; 
181 
prove "disj_left_commute" "(P(QR)) = (Q(PR))"; 

182 
val disj_comms = [disj_commute, disj_left_commute]; 

2134  183 
prove "disj_assoc" "((PQ)R) = (P(QR))"; 
1922  184 

923  185 
prove "conj_disj_distribL" "(P&(QR)) = (P&Q  P&R)"; 
186 
prove "conj_disj_distribR" "((PQ)&R) = (P&R  Q&R)"; 

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1892  188 
prove "disj_conj_distribL" "(P(Q&R)) = ((PQ) & (PR))"; 
189 
prove "disj_conj_distribR" "((P&Q)R) = ((PR) & (QR))"; 

190 

2134  191 
prove "imp_conjR" "(P > (Q&R)) = ((P>Q) & (P>R))"; 
192 
prove "imp_conjL" "((P&Q) >R) = (P > (Q > R))"; 

193 
prove "imp_disjL" "((PQ) > R) = ((P>R)&(Q>R))"; 

1892  194 

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prove "de_Morgan_disj" "(~(P  Q)) = (~P & ~Q)"; 
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196 
prove "de_Morgan_conj" "(~(P & Q)) = (~P  ~Q)"; 
1922  197 
prove "not_iff" "(P~=Q) = (P = (~Q))"; 
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198 

2134  199 
(*Avoids duplication of subgoals after expand_if, when the true and false 
200 
cases boil down to the same thing.*) 

201 
prove "cases_simp" "((P > Q) & (~P > Q)) = Q"; 

202 

1660  203 
prove "not_all" "(~ (! x.P(x))) = (? x.~P(x))"; 
1922  204 
prove "imp_all" "((! x. P x) > Q) = (? x. P x > Q)"; 
1660  205 
prove "not_ex" "(~ (? x.P(x))) = (! x.~P(x))"; 
1922  206 
prove "imp_ex" "((? x. P x) > Q) = (! x. P x > Q)"; 
1660  207 

1655  208 
prove "ex_disj_distrib" "(? x. P(x)  Q(x)) = ((? x. P(x))  (? x. Q(x)))"; 
209 
prove "all_conj_distrib" "(!x. P(x) & Q(x)) = ((! x. P(x)) & (! x. Q(x)))"; 

210 

2134  211 
(* '&' congruence rule: not included by default! 
212 
May slow rewrite proofs down by as much as 50% *) 

213 

214 
let val th = prove_goal HOL.thy 

215 
"(P=P')> (P'> (Q=Q'))> ((P&Q) = (P'&Q'))" 

216 
(fn _=> [fast_tac HOL_cs 1]) 

217 
in bind_thm("conj_cong",standard (impI RSN (2, th RS mp RS mp))) end; 

218 

219 
let val th = prove_goal HOL.thy 

220 
"(Q=Q')> (Q'> (P=P'))> ((P&Q) = (P'&Q'))" 

221 
(fn _=> [fast_tac HOL_cs 1]) 

222 
in bind_thm("rev_conj_cong",standard (impI RSN (2, th RS mp RS mp))) end; 

223 

224 
(* '' congruence rule: not included by default! *) 

225 

226 
let val th = prove_goal HOL.thy 

227 
"(P=P')> (~P'> (Q=Q'))> ((PQ) = (P'Q'))" 

228 
(fn _=> [fast_tac HOL_cs 1]) 

229 
in bind_thm("disj_cong",standard (impI RSN (2, th RS mp RS mp))) end; 

230 

231 
prove "eq_sym_conv" "(x=y) = (y=x)"; 

232 

233 
qed_goalw "o_apply" HOL.thy [o_def] "(f o g) x = f (g x)" 

234 
(fn _ => [rtac refl 1]); 

235 

236 
qed_goal "meta_eq_to_obj_eq" HOL.thy "x==y ==> x=y" 

237 
(fn [prem] => [rewtac prem, rtac refl 1]); 

238 

239 
qed_goalw "if_True" HOL.thy [if_def] "(if True then x else y) = x" 

240 
(fn _=>[fast_tac (HOL_cs addIs [select_equality]) 1]); 

241 

242 
qed_goalw "if_False" HOL.thy [if_def] "(if False then x else y) = y" 

243 
(fn _=>[fast_tac (HOL_cs addIs [select_equality]) 1]); 

244 

245 
qed_goal "if_P" HOL.thy "P ==> (if P then x else y) = x" 

246 
(fn [prem] => [ stac (prem RS eqTrueI) 1, rtac if_True 1 ]); 

247 
(* 

248 
qed_goal "if_not_P" HOL.thy "~P ==> (if P then x else y) = y" 

249 
(fn [prem] => [ stac (prem RS not_P_imp_P_iff_F) 1, rtac if_False 1 ]); 

250 
*) 

251 
qed_goalw "if_not_P" HOL.thy [if_def] "!!P. ~P ==> (if P then x else y) = y" 

252 
(fn _ => [fast_tac (HOL_cs addIs [select_equality]) 1]); 

253 

254 
qed_goal "expand_if" HOL.thy 

255 
"P(if Q then x else y) = ((Q > P(x)) & (~Q > P(y)))" 

256 
(fn _=> [ (res_inst_tac [("Q","Q")] (excluded_middle RS disjE) 1), 

257 
stac if_P 2, 

258 
stac if_not_P 1, 

259 
REPEAT(fast_tac HOL_cs 1) ]); 

260 

261 
qed_goal "if_bool_eq" HOL.thy 

262 
"(if P then Q else R) = ((P>Q) & (~P>R))" 

263 
(fn _ => [rtac expand_if 1]); 

264 

2263  265 
local val mktac = mk_case_split_tac (meta_eq_to_obj_eq RS iffD2) 
266 
in 

267 
fun split_tac splits = mktac (map mk_meta_eq splits) 

268 
end; 

269 

270 
local val mktac = mk_case_split_inside_tac (meta_eq_to_obj_eq RS iffD2) 

271 
in 

272 
fun split_inside_tac splits = mktac (map mk_meta_eq splits) 

273 
end; 

274 

275 

2251  276 
qed_goal "if_cancel" HOL.thy "(if c then x else x) = x" 
277 
(fn _ => [split_tac [expand_if] 1, fast_tac HOL_cs 1]); 

278 

2134  279 
(** 'if' congruence rules: neither included by default! *) 
280 

281 
(*Simplifies x assuming c and y assuming ~c*) 

282 
qed_goal "if_cong" HOL.thy 

283 
"[ b=c; c ==> x=u; ~c ==> y=v ] ==>\ 

284 
\ (if b then x else y) = (if c then u else v)" 

285 
(fn rew::prems => 

286 
[stac rew 1, stac expand_if 1, stac expand_if 1, 

287 
fast_tac (HOL_cs addDs prems) 1]); 

288 

289 
(*Prevents simplification of x and y: much faster*) 

290 
qed_goal "if_weak_cong" HOL.thy 

291 
"b=c ==> (if b then x else y) = (if c then x else y)" 

292 
(fn [prem] => [rtac (prem RS arg_cong) 1]); 

293 

294 
(*Prevents simplification of t: much faster*) 

295 
qed_goal "let_weak_cong" HOL.thy 

296 
"a = b ==> (let x=a in t(x)) = (let x=b in t(x))" 

297 
(fn [prem] => [rtac (prem RS arg_cong) 1]); 

298 

299 
(*In general it seems wrong to add distributive laws by default: they 

300 
might cause exponential blowup. But imp_disjL has been in for a while 

301 
and cannot be removed without affecting existing proofs. Moreover, 

302 
rewriting by "(PQ > R) = ((P>R)&(Q>R))" might be justified on the 

303 
grounds that it allows simplification of R in the two cases.*) 

304 

305 
val mksimps_pairs = 

306 
[("op >", [mp]), ("op &", [conjunct1,conjunct2]), 

307 
("All", [spec]), ("True", []), ("False", []), 

308 
("If", [if_bool_eq RS iffD1])]; 

1758  309 

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val HOL_base_ss = empty_ss 
2082  311 
setmksimps (mksimps mksimps_pairs) 
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312 
setsubgoaler asm_simp_tac; 
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val HOL_min_ss = HOL_base_ss setsolver (fn ps => 
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315 
FIRST'[resolve_tac (TrueI::refl::ps), atac, etac FalseE]); 
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val HOL_safe_min_ss = HOL_base_ss setsolver (fn ps => 
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FIRST'[match_tac (TrueI::refl::ps), eq_assume_tac, ematch_tac[FalseE]]); 
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320 
val HOL_ss = HOL_min_ss 
2251  321 
addsimps ([if_True, if_False, if_cancel, 
322 
o_apply, imp_disjL, conj_assoc, disj_assoc, 

2082  323 
de_Morgan_conj, de_Morgan_disj, not_all, not_ex, cases_simp] 
324 
@ ex_simps @ all_simps @ simp_thms) 

325 
addcongs [imp_cong]; 

326 

327 

1655  328 
qed_goal "if_distrib" HOL.thy 
329 
"f(if c then x else y) = (if c then f x else f y)" 

330 
(fn _ => [simp_tac (HOL_ss setloop (split_tac [expand_if])) 1]); 

331 

2097  332 
qed_goalw "o_assoc" HOL.thy [o_def] "f o (g o h) = f o g o h" 
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333 
(fn _ => [rtac ext 1, rtac refl 1]); 
1984  334 

335 

336 

337 

338 
(*** Install simpsets and datatypes in theory structure ***) 

339 

2251  340 
simpset := HOL_ss; 
1984  341 

342 
exception SS_DATA of simpset; 

343 

344 
let fun merge [] = SS_DATA empty_ss 

345 
 merge ss = let val ss = map (fn SS_DATA x => x) ss; 

346 
in SS_DATA (foldl merge_ss (hd ss, tl ss)) end; 

347 

348 
fun put (SS_DATA ss) = simpset := ss; 

349 

350 
fun get () = SS_DATA (!simpset); 

351 
in add_thydata "HOL" 

352 
("simpset", ThyMethods {merge = merge, put = put, get = get}) 

353 
end; 

354 

355 
type dtype_info = {case_const:term, case_rewrites:thm list, 

356 
constructors:term list, nchotomy:thm, case_cong:thm}; 

357 

358 
exception DT_DATA of (string * dtype_info) list; 

359 
val datatypes = ref [] : (string * dtype_info) list ref; 

360 

361 
let fun merge [] = DT_DATA [] 

362 
 merge ds = 

363 
let val ds = map (fn DT_DATA x => x) ds; 

364 
in DT_DATA (foldl (gen_union eq_fst) (hd ds, tl ds)) end; 

365 

366 
fun put (DT_DATA ds) = datatypes := ds; 

367 

368 
fun get () = DT_DATA (!datatypes); 

369 
in add_thydata "HOL" 

370 
("datatypes", ThyMethods {merge = merge, put = put, get = get}) 

371 
end; 

372 

373 

374 
add_thy_reader_file "thy_data.ML"; 