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inferPropsScript.sml
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inferPropsScript.sml
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(*
Various lemmas that are handy in the soundness and completeness
proofs of the type inferencer.
*)
open preamble;
open libTheory namespacePropsTheory typeSystemTheory astTheory semanticPrimitivesTheory inferTheory unifyTheory infer_tTheory;
open astPropsTheory typeSysPropsTheory;
val _ = new_theory "inferProps";
Theorem ienv_unchanged[simp]:
(ienv with inf_v := ienv.inf_v) = ienv ∧
(ienv with inf_c := ienv.inf_c) = ienv ∧
(ienv with inf_t := ienv.inf_t) = ienv
Proof
rw [inf_env_component_equality]
QED
Theorem extend_dec_ienv_empty:
!ienv.
extend_dec_ienv ienv <| inf_v := nsEmpty; inf_c := nsEmpty; inf_t := nsEmpty |> = ienv ∧
extend_dec_ienv <| inf_v := nsEmpty; inf_c := nsEmpty; inf_t := nsEmpty |> ienv = ienv
Proof
rw [extend_dec_ienv_def, inf_env_component_equality]
QED
(* ---------- Facts about deBruijn increment ---------- *)
Theorem infer_deBruijn_inc0:
!(n:num) t. infer_deBruijn_inc 0 t = t
Proof
ho_match_mp_tac infer_deBruijn_inc_ind >>
rw [infer_deBruijn_inc_def] >>
induct_on `ts` >>
rw []
QED
Theorem infer_deBruijn_inc0_id:
infer_deBruijn_inc 0 = (\x.x)
Proof
metis_tac [infer_deBruijn_inc0]
QED
Theorem t_vars_inc:
!tvs t. t_vars (infer_deBruijn_inc tvs t) = t_vars t
Proof
ho_match_mp_tac infer_deBruijn_inc_ind >>
rw [t_vars_def, encode_infer_t_def, infer_deBruijn_inc_def] >>
induct_on `ts` >>
rw [encode_infer_t_def]
QED
Theorem inc_wfs:
!tvs s. t_wfs s ⇒ t_wfs (infer_deBruijn_inc tvs o_f s)
Proof
rw [t_wfs_eqn] >>
`t_vR s = t_vR (infer_deBruijn_inc tvs o_f s)`
by (rw [FLOOKUP_o_f, FUN_EQ_THM, t_vR_eqn] >>
full_case_tac >>
rw [t_vars_inc]) >>
metis_tac []
QED
Theorem vwalk_inc:
!s tvs n.
t_wfs s
⇒
t_vwalk (infer_deBruijn_inc tvs o_f s) n = infer_deBruijn_inc tvs (t_vwalk s n)
Proof
rw [] >>
imp_res_tac (DISCH_ALL t_vwalk_ind) >>
`t_wfs (infer_deBruijn_inc tvs o_f s)` by metis_tac [inc_wfs] >>
rw [] >>
Q.SPEC_TAC (`n`, `n`) >>
qpat_x_assum `!p. (!v. q v ⇒ p v) ⇒ !v. p v` ho_match_mp_tac >>
rw [] >>
imp_res_tac t_vwalk_eqn >>
once_asm_rewrite_tac [] >>
pop_assum (fn _ => all_tac) >>
pop_assum (fn _ => all_tac) >>
cases_on `FLOOKUP s n` >>
rw [FLOOKUP_o_f, infer_deBruijn_inc_def] >>
cases_on `x` >>
rw [infer_deBruijn_inc_def]
QED
Theorem walk_inc:
!s tvs t.
t_wfs s
⇒
t_walk (infer_deBruijn_inc tvs o_f s) (infer_deBruijn_inc tvs t) = infer_deBruijn_inc tvs (t_walk s t)
Proof
rw [] >>
cases_on `t` >>
rw [t_walk_eqn, infer_deBruijn_inc_def, vwalk_inc]
QED
Theorem walkstar_inc:
!tvs s t.
t_wfs s ⇒
(t_walkstar (infer_deBruijn_inc tvs o_f s) (infer_deBruijn_inc tvs t) =
infer_deBruijn_inc tvs (t_walkstar s t))
Proof
rw [] >>
imp_res_tac t_walkstar_ind >>
Q.SPEC_TAC (`t`, `t`) >>
pop_assum ho_match_mp_tac >>
rw [] >>
rw [walk_inc] >>
cases_on `t_walk s t` >>
rw [infer_deBruijn_inc_def] >>
imp_res_tac inc_wfs >>
rw [t_walkstar_eqn,infer_deBruijn_inc_def, walk_inc] >>
pop_assum (fn _ => all_tac) >>
pop_assum mp_tac >>
pop_assum (fn _ => all_tac) >>
induct_on `l` >>
rw [] >>
fs []
QED
Theorem walkstar_inc2:
!tvs s n.
t_wfs s ⇒
(t_walkstar (infer_deBruijn_inc tvs o_f s) (Infer_Tuvar n) =
infer_deBruijn_inc tvs (t_walkstar s (Infer_Tuvar n)))
Proof
rw [GSYM walkstar_inc, infer_deBruijn_inc_def]
QED
(* ---------- Type substitution ---------- *)
Theorem subst_infer_subst_swap:
(!t tvs s uvar.
t_wfs s ⇒
(t_walkstar s (infer_type_subst (ZIP (tvs, MAP (λn. Infer_Tuvar (uvar + n)) (COUNT_LIST (LENGTH tvs)))) t)
=
infer_type_subst (ZIP (tvs, MAP (λn. t_walkstar s (Infer_Tuvar (uvar + n))) (COUNT_LIST (LENGTH tvs)))) t)) ∧
(!ts tvs s uvar.
t_wfs s ⇒
(MAP (t_walkstar s) (MAP (infer_type_subst (ZIP (tvs, MAP (λn. Infer_Tuvar (uvar + n)) (COUNT_LIST (LENGTH tvs))))) ts)
=
MAP (infer_type_subst (ZIP (tvs, MAP (λn. t_walkstar s (Infer_Tuvar (uvar + n))) (COUNT_LIST (LENGTH tvs))))) ts))
Proof
ho_match_mp_tac t_induction >>
rw [type_subst_def, infer_type_subst_alt, t_walkstar_eqn1]
>- (every_case_tac >>
rw [t_walkstar_eqn1] >>
fs [ALOOKUP_FAILS] >>
fs [MAP_ZIP, LENGTH_COUNT_LIST, ALOOKUP_ZIP_MAP_SND] >>
imp_res_tac ALOOKUP_MEM >>
fs [MEM_ZIP, LENGTH_COUNT_LIST] >>
metis_tac [])
QED
val infer_t_induction = infer_tTheory.infer_t_induction;
Theorem infer_subst_FEMPTY:
(!t. infer_subst FEMPTY t = t) ∧
(!ts. MAP (infer_subst FEMPTY) ts = ts)
Proof
ho_match_mp_tac infer_t_induction >>
rw [SUBSET_DEF, infer_subst_def] >>
metis_tac []
QED
Theorem infer_subst_submap:
(!t s1 s2 m.
s1 SUBMAP s2 ∧
{uv | uv ∈ t_vars t ∧ m ≤ uv} ⊆ FDOM s1 ∧
(!uv. uv ∈ FDOM s2 DIFF FDOM s1 ⇒ m ≤ uv)
⇒
(infer_subst s1 t = infer_subst s2 t)) ∧
(!ts s1 s2 m.
s1 SUBMAP s2 ∧
{uv | ?s. uv ∈ s ∧ MEM s (MAP t_vars ts) ∧ m ≤ uv} ⊆ FDOM s1 ∧
(!uv. uv ∈ FDOM s2 DIFF FDOM s1 ⇒ m ≤ uv)
⇒
(MAP (infer_subst s1) ts = MAP (infer_subst s2) ts))
Proof
ho_match_mp_tac infer_t_induction >>
rw [SUBSET_DEF, infer_subst_def, t_vars_eqn]
>-
metis_tac []
>- (
full_case_tac >>
full_case_tac >>
rw [] >>
fs [SUBMAP_DEF, FLOOKUP_DEF] >>
metis_tac [])
>-
metis_tac []
>>
metis_tac []
QED
Theorem generalise_list_length:
∀a b c d e f g.
generalise_list a b c d = (e,f,g) ⇒ LENGTH g = LENGTH d
Proof
Induct_on`d`>>fs[generalise_def]>>rw[]>>
pairarg_tac>>fs[]>>
pairarg_tac>>fs[]>>
res_tac>>fs[]>>rveq>>fs[]
QED
Theorem generalise_subst:
(!t m n s tvs s' t'.
(generalise m n s t = (tvs, s', t'))
⇒
(s SUBMAP s') ∧
(FDOM s' = FDOM s ∪ { uv | uv ∈ t_vars t ∧ m ≤ uv }) ∧
(!uv. uv ∈ FDOM s' DIFF FDOM s ⇒ ∃tv. (FAPPLY s' uv = tv) ∧ n ≤ tv ∧ tv < tvs + n) ∧
(!uv. uv ∈ t_vars t' ⇒ uv < m) ∧
(infer_subst s' t = infer_subst s t')) ∧
(!ts m n s tvs s' ts'.
(generalise_list m n s ts = (tvs, s', ts'))
⇒
(s SUBMAP s') ∧
(FDOM s' = FDOM s ∪ { uv | uv ∈ BIGUNION (set (MAP t_vars ts)) ∧ m ≤ uv }) ∧
(!uv. uv ∈ FDOM s' DIFF FDOM s ⇒ ∃tv. (FAPPLY s' uv = tv) ∧ n ≤ tv ∧ tv < tvs + n) ∧
(!uv. uv ∈ BIGUNION (set (MAP t_vars ts')) ⇒ uv < m) ∧
(MAP (infer_subst s') ts = MAP (infer_subst s) ts'))
Proof
Induct >>
SIMP_TAC (srw_ss()) [t_vars_eqn, generalise_def, infer_subst_def]
>- (
REPEAT GEN_TAC >>
STRIP_TAC >>
fs[]>>pairarg_tac>>fs[]>>
first_x_assum old_drule>> simp[]>>
rveq>>fs[]>>
rw [EXTENSION, infer_subst_def] >>
fs [t_vars_eqn] >>
metis_tac [])
>- (
rw [] >>
every_case_tac >>
fs [] >>
rw [] >>
rw [FLOOKUP_DEF, EXTENSION] >>
TRY (EQ_TAC) >>
rw [] >>
fs [FLOOKUP_DEF, infer_subst_def, t_vars_eqn] >>
decide_tac)
>>
REPEAT GEN_TAC >>
STRIP_TAC >>
`?tvs s' t'. generalise m n s t = (tvs, s', t')`
by (cases_on `generalise m n s t` >>
rw [] >>
cases_on `r` >>
fs []) >>
fs [LET_THM] >>
`?tvs s' ts'. generalise_list m (tvs'+n) s'' ts = (tvs, s', ts')`
by (cases_on `generalise_list m (tvs'+n) s'' ts` >>
rw [] >>
cases_on `r` >>
fs []) >>
fs [LET_THM] >>
qpat_x_assum `!m'. P m'`
(mp_tac o Q.SPECL [`m`, `tvs'+n`, `s''`, `tvs''`, `s'''`, `ts''`]) >>
qpat_x_assum `!m'. P m'`
(mp_tac o Q.SPECL [`m`, `n`, `s`, `tvs'`, `s''`, `t'`]) >>
rw [INTER_UNION]
>-
metis_tac [SUBMAP_TRANS]
>- (rw [EXTENSION] >> metis_tac [])
>- (
`uv ∈ FDOM s''` by fs [] >>
res_tac >>
rw [INTER_UNION] >>
fs [SUBMAP_DEF])
>- (
`uv ∈ FDOM s''` by fs [] >>
res_tac >>
rw [INTER_UNION] >>
fs [SUBMAP_DEF] >>
res_tac >>
decide_tac)
>- (
`uv ∈ FDOM s'` by (fs [] >> metis_tac []) >>
cases_on `uv ∈ t_vars t` >>
rw [] >>
res_tac >>
rw [INTER_UNION] >>
fs [SUBMAP_DEF] >>
res_tac >>
decide_tac)
>- (
`uv ∈ FDOM s'` by (fs [] >> metis_tac []) >>
cases_on `uv ∈ t_vars t` >>
rw [] >>
`uv ∈ FDOM s''` by (fs [] >> metis_tac []) >>
res_tac >>
rw [INTER_UNION] >>
fs [SUBMAP_DEF] >>
res_tac >>
decide_tac)
>- metis_tac []
>- metis_tac []
>- (
`{uv | uv ∈ t_vars t ∧ m ≤ uv} ⊆ FDOM s'' ∧
(!uv. uv ∈ FDOM s' DIFF FDOM s'' ⇒ m ≤ uv)` by
rw [SUBSET_DEF] >>
metis_tac [infer_subst_submap])
>>
`{uv | ∃s. uv ∈ s ∧ MEM s (MAP t_vars ts'') ∧ m ≤ uv} ⊆ FDOM s ∧ (!uv. uv ∈ FDOM s'' DIFF FDOM s ⇒ m ≤ uv)` by
(rw [SUBSET_DEF] >>
`¬(x < m)` by decide_tac >>
metis_tac []) >>
metis_tac [infer_subst_submap]
QED
Theorem generalise_subst_empty:
!n ts tvs s ts'.
(generalise_list 0 n FEMPTY ts = (tvs, s, ts'))
⇒
(FDOM s = { uv | uv ∈ BIGUNION (set (MAP t_vars ts)) }) ∧
(!uv. uv ∈ FDOM s ⇒ ∃tv. (FAPPLY s uv = tv) ∧ tv < tvs + n) ∧
(BIGUNION (set (MAP t_vars ts')) = {}) ∧
(ts' = MAP (infer_subst s) ts)
Proof
rw [] >>
imp_res_tac generalise_subst >>
fs [] >>
rw []
>- (
rw [BIGUNION, EXTENSION] >>
metis_tac [])
>- (
fs [EXTENSION] >>
metis_tac [])
>- (
cases_on `ts'` >>
rw [] >>
rw [EXTENSION] >>
eq_tac >>
rw [] >>
fs [t_vars_eqn] >>
metis_tac [])
>>
metis_tac [infer_subst_FEMPTY]
QED
(* ---------- Dealing with the monad ---------- *)
(* TODO: update *)
Theorem infer_st_rewrs:
(!st. (st with next_uvar := st.next_uvar) = st) ∧
(!st. (st with subst := st.subst) = st) ∧
(!st s. (st with subst := s).subst = s) ∧
(!st s. (st with subst := s).next_uvar = st.next_uvar) ∧
(!st uv. (st with next_uvar := uv).next_uvar = uv) ∧
(!st uv. (st with next_uvar := uv).subst = st.subst)
Proof
rw [] >>
cases_on `st` >>
rw [infer_st_component_equality]
QED
val st_ex_return_success = Q.prove (
`!v st v' st'.
(st_ex_return v st = (Success v', st')) =
((v = v') ∧ (st = st'))`,
rw [st_ex_return_def]);
val st_ex_bind_success = Q.prove (
`!f g st st' v.
(st_ex_bind f g st = (Success v, st')) =
?v' st''. (f st = (Success v', st'')) /\ (g v' st'' = (Success v, st'))`,
rw [st_ex_bind_def] >>
cases_on `f st` >>
rw [] >>
cases_on `q` >>
rw []);
val fresh_uvar_success = Q.prove (
`!st t st'.
(fresh_uvar st = (Success t, st')) =
((t = Infer_Tuvar st.next_uvar) ∧
(st' = st with next_uvar := st.next_uvar + 1))`,
rw [fresh_uvar_def] >>
metis_tac []);
Theorem n_fresh_uvar_success:
!n st ts st'.
(n_fresh_uvar n st = (Success ts, st')) =
((ts = MAP (\n. Infer_Tuvar (st.next_uvar + n)) (COUNT_LIST n)) ∧
(st' = st with next_uvar := st.next_uvar + n))
Proof
ho_match_mp_tac n_fresh_uvar_ind >>
rw [] >>
rw [st_ex_return_success, Once n_fresh_uvar_def, COUNT_LIST_SNOC,
st_ex_bind_success, fresh_uvar_success, infer_st_rewrs] >-
metis_tac [] >>
fs [] >>
srw_tac [ARITH_ss] [] >>
rw [count_list_sub1, MAP_APPEND, MAP_MAP_o, combinTheory.o_DEF] >>
eq_tac >>
srw_tac [ARITH_ss] [arithmeticTheory.ADD1]
QED
val apply_subst_success = Q.prove (
`!t1 st1 t2 st2.
(apply_subst t1 st1 = (Success t2, st2))
=
((st2 = st1) ∧
(t2 = t_walkstar st1.subst t1))`,
rw [st_ex_return_def, st_ex_bind_def, LET_THM, apply_subst_def, read_def] >>
eq_tac >>
rw []);
Theorem add_constraint_success:
!l t1 t2 st st' x.
(add_constraint l t1 t2 st = (Success x, st'))
=
((x = ()) ∧ (?s. (t_unify st.subst t1 t2 = SOME s) ∧ (st' = st with subst := s)))
Proof
rw [add_constraint_def] >>
full_case_tac >>
metis_tac []
QED
val add_constraints_success = Q.prove (
`!l ts1 ts2 st st' x.
(add_constraints l ts1 ts2 st = (Success x, st'))
=
((LENGTH ts1 = LENGTH ts2) ∧
((x = ()) ∧
(st.next_uvar = st'.next_uvar) ∧
(st.next_id = st'.next_id) ∧
pure_add_constraints st.subst (ZIP (ts1,ts2)) st'.subst))`,
ho_match_mp_tac add_constraints_ind >>
rw [add_constraints_def, pure_add_constraints_def, st_ex_return_success,
failwith_def, st_ex_bind_success, add_constraint_success] >>
TRY (cases_on `x`) >>
rw [pure_add_constraints_def] >-
metis_tac [infer_st_component_equality] >>
eq_tac >>
rw [] >>
cases_on `t_unify st.subst t1 t2` >>
fs []);
val add_constraints_nil2_success = Q.prove (
`(add_constraints l ts1 [] st = (Success x, st'))
= (ts1 = [] /\ st = st')`,
Cases_on `ts1` \\ simp [add_constraints_def]
\\ simp [failwith_def, st_ex_bind_success, st_ex_return_success]
);
val add_constraints_cons2_success = Q.prove (
`(add_constraints l ts1 (t2 :: ts2) st = (Success x, st'))
= (?t1 tl1 st''. ts1 = t1 :: tl1 /\
add_constraint l t1 t2 st = (Success (), st'') /\
add_constraints l tl1 ts2 st'' = (Success x, st'))`,
Cases_on `ts1` \\ simp [add_constraints_def]
\\ simp [failwith_def, st_ex_bind_success, st_ex_return_success]
);
val failwith_success = Q.prove (
`!l m st v st'. (failwith l m st = (Success v, st')) = F`,
rw [failwith_def]);
val lookup_st_ex_success = Q.prove (
`!loc x err l st v st'.
(lookup_st_ex loc err x l st = (Success v, st'))
=
((nsLookup l x = SOME v) ∧ (st = st'))`,
rw [lookup_st_ex_def, failwith_def, st_ex_return_success]
>> every_case_tac);
val op_data = {nchotomy = op_nchotomy, case_def = op_case_def};
val op_case_eq = prove_case_eq_thm op_data;
val op_case_rand = prove_case_rand_thm op_data;
val list_data = {nchotomy = list_nchotomy, case_def = list_case_def}
val list_case_eq = prove_case_eq_thm list_data;
val list_case_rand = prove_case_rand_thm list_data;
val bool_data = {nchotomy = TypeBase.nchotomy_of bool,
case_def = TypeBase.case_def_of bool}
val bool_case_rand = prove_case_rand_thm bool_data;
fun mk_case_rator case_rand =
case_rand
|> GEN (case_rand |> concl |> lhs |> rator)
|> ISPEC (let val z = genvar(gen_tyvar())
val r = genvar(type_of z --> gen_tyvar())
in mk_abs(r,mk_comb(r,z)) end)
|> BETA_RULE
val list_case_rator = mk_case_rator list_case_rand
val op_case_rator = mk_case_rator op_case_rand
val bool_case_rator = mk_case_rator bool_case_rand
Theorem UNCURRY_rator:
UNCURRY f x y = UNCURRY (\a b. f a b y) x
Proof
Cases_on `x` \\ simp []
QED
Triviality constrain_op_op_case:
constrain_op l op ts st = (case op of
Opapp => let x = () in constrain_op l op ts st
| _ => constrain_op l op ts st)
Proof
CASE_TAC \\ simp []
QED
val constrain_op_success =
``(constrain_op l op ts st = (Success v, st'))``
|> (REWRITE_CONV [Once constrain_op_op_case, op_case_eq]
THENC SIMP_CONV (srw_ss () ++ CONJ_ss) [constrain_op_dtcase_def,
op_simple_constraints_def, LET_THM, bool_case_eq,
st_ex_bind_success,st_ex_return_success,
add_constraint_success,failwith_success,
add_constraints_cons2_success,
add_constraints_nil2_success,
list_case_rator, list_case_eq, bool_case_rator, bool_case_eq,
PULL_EXISTS]
)
val _ = save_thm ("constrain_op_success", constrain_op_success);
val get_next_uvar_success = Q.prove (
`!st v st'.
(get_next_uvar st = (Success v, st'))
=
((v = st.next_uvar) ∧ (st = st'))`,
rw [get_next_uvar_def] >>
metis_tac []);
val apply_subst_list_success =
SIMP_CONV (srw_ss()) [apply_subst_list_def, LET_THM]
``(apply_subst_list ts st = (Success v, st'))``
val guard_success = Q.prove (
`∀P l m st v st'.
(guard P l m st = (Success v, st'))
=
(P ∧ (v = ()) ∧ (st = st'))`,
rw [guard_def, st_ex_return_def, failwith_def] >>
metis_tac []);
Theorem check_dups_success:
!l f ls s r s'.
check_dups l f ls s = (Success r, s')
⇔
s' = s ∧ ALL_DISTINCT ls
Proof
Induct_on `ls` >>
rw [check_dups_def, st_ex_return_def, failwith_def] >>
metis_tac []
QED
Theorem type_name_check_subst_success:
(!t l f tenvT tvs r (s:'a) s'.
type_name_check_subst l f tenvT tvs t s = (Success r, s')
⇔
s = s' ∧ r = type_name_subst tenvT t ∧
check_freevars_ast tvs t ∧ check_type_names tenvT t) ∧
(!ts l f tenvT tvs r (s:'a) s'.
type_name_check_subst_list l f tenvT tvs ts s = (Success r, s')
⇔
s = s' ∧ r = MAP (type_name_subst tenvT) ts ∧
EVERY (check_freevars_ast tvs) ts ∧ EVERY (check_type_names tenvT) ts)
Proof
Induct >>
rw [type_name_check_subst_def, st_ex_bind_def, guard_def, st_ex_return_def,
check_freevars_ast_def, check_type_names_def, failwith_def,
type_name_subst_def] >>
every_case_tac >>
fs [] >>
rw [] >>
TRY pairarg_tac >>
fs [] >>
every_case_tac >>
fs [lookup_st_ex_success, lookup_st_ex_def] >>
metis_tac [exc_distinct, PAIR_EQ, NOT_EVERY]
QED
Theorem check_ctor_types_success:
!l tenvT tvs ts s s'.
check_ctor_types l tenvT tvs ts s = (Success (),s') ⇔
s = s' ∧
EVERY (λ(cn,ts). EVERY (check_freevars_ast tvs) ts ∧
EVERY (check_type_names tenvT) ts) ts
Proof
Induct_on `ts` >>
rw [check_ctor_types_def, st_ex_return_def] >>
PairCases_on `h` >>
rw [check_ctor_types_def, st_ex_bind_def] >>
every_case_tac >>
fs [type_name_check_subst_success] >>
CCONTR_TAC >>
fs [combinTheory.o_DEF] >>
metis_tac [exc_distinct, PAIR_EQ, type_name_check_subst_success]
QED
Theorem check_dup_ctors_thm:
check_dup_ctors (tvs,tn,condefs) = ALL_DISTINCT (MAP FST condefs)
Proof
rw [check_dup_ctors_def] >>
induct_on `condefs` >>
rw [] >>
pairarg_tac >>
fs [] >>
eq_tac >>
rw [] >>
induct_on `condefs` >>
rw [] >>
pairarg_tac >>
fs []
QED
Theorem check_ctors_success:
!l tenvT tds s s'.
ALL_DISTINCT (MAP (FST o SND) tds) ⇒
(check_ctors l tenvT tds s = (Success (),s') ⇔
s' = s ∧ check_ctor_tenv tenvT tds)
Proof
Induct_on `tds` >>
rw [] >>
TRY (PairCases_on `h`) >>
fs [check_ctor_tenv_def, check_type_definition_def, st_ex_bind_def,
check_ctors_def, st_ex_return_def, check_dup_ctors_thm]
>- metis_tac [] >>
every_case_tac >>
fs [check_dups_success, st_ex_return_def, check_type_definition_def,
check_ctor_types_success] >>
fs [check_dups_def, st_ex_return_def, st_ex_bind_def, LAMBDA_PROD,
combinTheory.o_DEF] >>
CCONTR_TAC >>
fs [combinTheory.o_DEF, ETA_THM] >>
rw [] >>
TRY (
Induct_on `h2` >>
fs [check_dups_def, st_ex_return_def] >>
rw [] >>
NO_TAC)
>- metis_tac [exc_distinct, PAIR_EQ, check_dups_success]
>- (
Induct_on `h2` >>
fs [] >>
rw [check_ctor_types_def, st_ex_return_def] >>
PairCases_on `h` >>
fs [check_ctor_types_def, st_ex_return_def, st_ex_bind_def] >>
every_case_tac >>
fs [type_name_check_subst_success] >>
rw [] >>
metis_tac [NOT_EVERY, exc_distinct, PAIR_EQ, type_name_check_subst_success])
>- metis_tac [exc_distinct, PAIR_EQ, check_dups_success]
>- metis_tac [exc_distinct, PAIR_EQ, check_dups_success]
>- metis_tac [exc_distinct, PAIR_EQ, check_dups_success]
QED
Theorem check_type_definition_success:
!l tenvT tds s r s'.
check_type_definition l tenvT tds s = (Success r, s')
⇔
s' = s ∧ check_ctor_tenv tenvT tds
Proof
rw [check_type_definition_def, st_ex_bind_def] >>
every_case_tac >>
fs [check_dups_success]
>- metis_tac [check_ctors_success] >>
`~ALL_DISTINCT (MAP (FST ∘ SND) tds)`
by metis_tac [exc_distinct, PAIR_EQ, check_dups_success] >>
pop_assum mp_tac >>
pop_assum kall_tac >>
Induct_on `tds` >>
rw [] >>
PairCases_on `h` >>
rw [check_ctor_tenv_def] >>
fs [LAMBDA_PROD, combinTheory.o_DEF]
QED
val option_case_eq = Q.prove (
`!opt f g v st st'.
((case opt of NONE => f | SOME x => g x) st = (Success v, st')) =
(((opt = NONE) ∧ (f st = (Success v, st'))) ∨ (?x. (opt = SOME x) ∧ (g x st = (Success v, st'))))`,
rw [] >>
cases_on `opt` >>
fs []);
val success_eqns =
LIST_CONJ [st_ex_return_success, st_ex_bind_success, fresh_uvar_success,
apply_subst_success, add_constraint_success, lookup_st_ex_success,
n_fresh_uvar_success, failwith_success, add_constraints_success,
oneTheory.one, check_type_definition_success,
get_next_uvar_success, apply_subst_list_success, guard_success,
read_def, option_case_eq, check_dups_success,
type_name_check_subst_success,
check_ctor_types_success,
check_ctors_success];
val _ = save_thm ("success_eqns", success_eqns);
Theorem remove_pair_lem:
(!f v. (\(x,y). f x y) v = f (FST v) (SND v)) ∧
(!f v. (\(x,y,z). f x y z) v = f (FST v) (FST (SND v)) (SND (SND v)))
Proof
rw [] >>
PairCases_on `v` >>
rw []
QED
(* ---------- Simple structural properties ---------- *)
Theorem infer_funs_length:
!l ienv funs ts st1 st2.
(infer_funs l ienv funs st1 = (Success ts, st2)) ⇒
(LENGTH funs = LENGTH ts)
Proof
induct_on `funs` >>
rw [infer_e_def, success_eqns] >>
rw [] >>
PairCases_on `h` >>
fs [infer_e_def, success_eqns] >>
rw [] >>
metis_tac []
QED
Theorem type_name_check_subst_state:
(!t l err tenvT fvs (st:'a) r st'. type_name_check_subst l err tenvT fvs t st = (r,st') ⇒ st = st') ∧
(!ts l err tenvT fvs (st:'a) r st'. type_name_check_subst_list l err tenvT fvs ts st = (r,st') ⇒ st = st')
Proof
Induct >>
rw [type_name_check_subst_def, st_ex_bind_def, guard_def, st_ex_return_def,
failwith_def, lookup_st_ex_def] >>
every_case_tac >>
fs [] >>
rw [] >>
TRY pairarg_tac >>
fs [] >>
every_case_tac >>
fs [] >>
metis_tac []
QED
Theorem infer_p_bindings:
(!l cenv p st t env st' x.
(infer_p l cenv p st = (Success (t,env), st'))
⇒
(pat_bindings p x = MAP FST env ++ x)) ∧
(!l cenv ps st ts env st' x.
(infer_ps l cenv ps st = (Success (ts,env), st'))
⇒
(pats_bindings ps x = MAP FST env ++ x))
Proof
ho_match_mp_tac infer_p_ind >>
rw [pat_bindings_def, infer_p_def, success_eqns, remove_pair_lem]
>- (PairCases_on `v'` >>
rw [] >>
metis_tac [])
>- (PairCases_on `v''` >>
rw [] >>
metis_tac [])
>- (PairCases_on `v'` >>
rw [] >>
metis_tac [])
>- (
PairCases_on `v'` >>
first_x_assum drule>>
simp[])
>- metis_tac []
>- (PairCases_on `v'` >>
PairCases_on `v''` >>
rw [] >>
metis_tac [APPEND_ASSOC])
QED
(* ---------- Dealing with the constraint set ---------- *)
val pure_add_constraints_append2 = Q.prove (
`!s1 ts s2 t1 t2.
t_wfs s1 ∧
pure_add_constraints s1 ts s2 ∧
(t_walkstar s1 t1 = t_walkstar s1 t2)
⇒
(t_walkstar s2 t1 = t_walkstar s2 t2)`,
induct_on `ts` >>
rw [pure_add_constraints_def] >>
rw [] >>
PairCases_on `h` >>
fs [pure_add_constraints_def] >>
metis_tac [t_unify_wfs, t_unify_apply2]);
Theorem pure_add_constraints_apply:
!s1 ts s2.
t_wfs s1 ∧
pure_add_constraints s1 ts s2
⇒
MAP (t_walkstar s2 o FST) ts = MAP (t_walkstar s2 o SND) ts
Proof
induct_on `ts` >>
rw [pure_add_constraints_def] >>
PairCases_on `h` >>
fs [pure_add_constraints_def] >>
metis_tac [t_unify_apply, pure_add_constraints_append2, t_unify_wfs]
QED
Theorem pure_add_constraints_append:
!s1 ts1 s3 ts2.
pure_add_constraints s1 (ts1 ++ ts2) s3
=
(?s2. pure_add_constraints s1 ts1 s2 ∧ pure_add_constraints s2 ts2 s3)
Proof
ho_match_mp_tac pure_add_constraints_ind >>
rw [pure_add_constraints_def] >>
metis_tac []
QED
Theorem infer_p_constraints:
(!l cenv p st t env st'.
(infer_p l cenv p st = (Success (t,env), st'))
⇒
(?ts. pure_add_constraints st.subst ts st'.subst)) ∧
(!l cenv ps st ts env st'.
(infer_ps l cenv ps st = (Success (ts,env), st'))
⇒
(?ts'. pure_add_constraints st.subst ts' st'.subst))
Proof
ho_match_mp_tac infer_p_ind >>
rw [infer_p_def, success_eqns, remove_pair_lem, GSYM FORALL_PROD] >>
rw [] >>
res_tac >>
fs [] >>
prove_tac [pure_add_constraints_append, pure_add_constraints_def, type_name_check_subst_state]
QED
Theorem infer_e_constraints:
(!l ienv e st st' t.
(infer_e l ienv e st = (Success t, st'))
⇒
(?ts. pure_add_constraints st.subst ts st'.subst)) ∧
(!l ienv es st st' ts.
(infer_es l ienv es st = (Success ts, st'))
⇒
(?ts. pure_add_constraints st.subst ts st'.subst)) ∧
(!l ienv pes t1 t2 st st'.
(infer_pes l ienv pes t1 t2 st = (Success (), st'))
⇒
(?ts. pure_add_constraints st.subst ts st'.subst)) ∧
(!l ienv funs st st' ts'.
(infer_funs l ienv funs st = (Success ts', st'))
⇒
(?ts. pure_add_constraints st.subst ts st'.subst))
Proof
ho_match_mp_tac infer_e_ind >>
rw [infer_e_def, constrain_op_success, success_eqns, remove_pair_lem, GSYM FORALL_PROD] >>
rw [] >>
res_tac >>
fs [] >>
TRY (cases_on `v'`) >>
every_case_tac >> TRY (Cases_on `uop:fp_uop`) >>
fs [success_eqns] >>
rw [] >>
fs [infer_st_rewrs] >>
TRY (prove_tac [pure_add_constraints_append, pure_add_constraints_def,
infer_p_constraints, type_name_check_subst_state])
QED
Theorem pure_add_constraints_wfs:
!s1 ts s2.
pure_add_constraints s1 ts s2 ∧
t_wfs s1
⇒
t_wfs s2
Proof
induct_on `ts` >>
rw [pure_add_constraints_def] >-
metis_tac [] >>
PairCases_on `h` >>
fs [pure_add_constraints_def] >>
metis_tac [t_unify_wfs]
QED
(* ---------- The next unification variable is monotone non-decreasing ---------- *)
Theorem infer_p_next_uvar_mono:
(!l cenv p st t env st'.
(infer_p l cenv p st = (Success (t,env), st'))
⇒
st.next_uvar ≤ st'.next_uvar) ∧
(!l cenv ps st ts env st'.
(infer_ps l cenv ps st = (Success (ts,env), st'))
⇒
st.next_uvar ≤ st'.next_uvar)
Proof
ho_match_mp_tac infer_p_ind >>
rw [infer_p_def, success_eqns, remove_pair_lem, GSYM FORALL_PROD] >>
rw [] >>
res_tac >>
fs [] >>
`st''' = st''` by metis_tac [type_name_check_subst_state] >>
metis_tac [DECIDE ``!(x:num) y z. x ≤ y ⇒ x ≤ y + z``,
arithmeticTheory.LESS_EQ_TRANS]
QED
Theorem infer_e_next_uvar_mono:
(!l ienv e st st' t.
(infer_e l ienv e st = (Success t, st'))
⇒
st.next_uvar ≤ st'.next_uvar) ∧
(!l ienv es st st' ts.
(infer_es l ienv es st = (Success ts, st'))
⇒
st.next_uvar ≤ st'.next_uvar) ∧
(!l ienv pes t1 t2 st st'.
(infer_pes l ienv pes t1 t2 st = (Success (), st'))
⇒
st.next_uvar ≤ st'.next_uvar) ∧
(!l ienv funs st st' ts.
(infer_funs l ienv funs st = (Success ts, st'))
⇒
st.next_uvar ≤ st'.next_uvar)
Proof
ho_match_mp_tac infer_e_ind >>
rw [infer_e_def, constrain_op_success, success_eqns, remove_pair_lem, GSYM FORALL_PROD] >>
rw [] >>
res_tac >>
fs [] >>
every_case_tac >> TRY (Cases_on `uop:fp_uop`) >>
fs [success_eqns]>>
metis_tac [infer_p_next_uvar_mono, arithmeticTheory.LESS_EQ_TRANS,
pair_CASES,type_name_check_subst_state,
DECIDE ``!(x:num) y. x ≤ x + y``,
DECIDE ``!(x:num) y. x + 1 ≤ y ⇒ x ≤ y``,
DECIDE ``!(x:num) y z. x ≤ y ⇒ x ≤ y + z``]
QED
(* ---------- The inferencer builds well-formed substitutions ---------- *)
Theorem infer_p_wfs:
(!l cenv p st t env st'.
t_wfs st.subst ∧
(infer_p l cenv p st = (Success (t,env), st'))
⇒
t_wfs st'.subst) ∧
(!l cenv ps st ts env st'.
t_wfs st.subst ∧
(infer_ps l cenv ps st = (Success (ts,env), st'))
⇒
t_wfs st'.subst)
Proof
ho_match_mp_tac infer_p_ind >>
rw [infer_p_def, success_eqns, remove_pair_lem, GSYM FORALL_PROD] >>
rw [] >>
res_tac >>
fs []
>- prove_tac [pure_add_constraints_wfs]
>- metis_tac [t_unify_wfs, type_name_check_subst_state]
QED
Theorem infer_e_wfs:
(!l ienv e st st' t.
infer_e l ienv e st = (Success t, st') ∧
t_wfs st.subst
⇒
t_wfs st'.subst) ∧
(!l ienv es st st' ts.
infer_es l ienv es st = (Success ts, st') ∧
t_wfs st.subst
⇒
t_wfs st'.subst) ∧
(!l ienv pes t1 t2 st st'.
infer_pes l ienv pes t1 t2 st = (Success (), st') ∧
t_wfs st.subst
⇒
t_wfs st'.subst) ∧
(!l ienv funs st st' ts'.
infer_funs l ienv funs st = (Success ts', st') ∧
t_wfs st.subst
⇒
t_wfs st'.subst)
Proof
ho_match_mp_tac infer_e_ind >>
rw [infer_e_def, constrain_op_success, success_eqns, remove_pair_lem, GSYM FORALL_PROD] >>
fs [] >>
res_tac >>
imp_res_tac t_unify_wfs >>
fs [] >>
imp_res_tac pure_add_constraints_wfs >>
fs [] >>
TRY (cases_on `v'`) >>
imp_res_tac infer_p_wfs >>
fs [] >>
every_case_tac >> TRY (cases_on `uop:fp_uop`) >>
fs [success_eqns] >>
rw [] >>
fs [infer_st_rewrs] >>
res_tac >>
fs [] >>
imp_res_tac t_unify_wfs >>
metis_tac [type_name_check_subst_state]
QED
(* ---------- The invariants of the inferencer ---------- *)