header {*
{\em abacus} a kind of register machine
*}
theory abacus
imports Main StateMonad
begin
text {*
{\em Abacus} instructions:
*}
datatype abc_inst =
-- {* @{text "Inc n"} increments the memory cell (or register)
with address @{text "n"} by one.
*}
Inc nat
-- {*
@{text "Dec n label"} decrements the memory cell with address @{text "n"} by one.
If cell @{text "n"} is already zero, no decrements happens and the executio jumps to
the instruction labeled by @{text "label"}.
*}
| Dec nat nat
-- {*
@{text "Goto label"} unconditionally jumps to the instruction labeled by @{text "label"}.
*}
| Goto nat
fun splits :: "'a set \<Rightarrow> ('a set \<times> 'a set) \<Rightarrow> bool"
where "splits s (u, v) = (u \<union> v = s \<and> u \<inter> v = {})"
declare splits.simps [simp del]
definition "stimes p q = {s . \<exists> u v. u \<in> p \<and> v \<in> q \<and> splits s (u, v)}"
lemmas st_def = stimes_def[unfolded splits.simps]
notation stimes (infixr "*" 70)
lemma stimes_comm: "(p::('a set set)) * q = q * p"
by (unfold st_def, auto)
lemma splits_simp: "splits s (u, v) = (v = (s - u) \<and> v \<subseteq> s \<and> u \<subseteq> s)"
by (unfold splits.simps, auto)
lemma stimes_assoc: "p * q * r = (p * q) * (r::'a set set)"
by (unfold st_def, blast)
definition
"emp = {{}}"
lemma emp_unit_r [simp]: "p * emp = p"
by (unfold st_def emp_def, auto)
lemma emp_unit_l [simp]: "emp * p = p"
by (metis emp_unit_r stimes_comm)
lemma stimes_mono: "p \<subseteq> q \<Longrightarrow> p * r \<subseteq> q * r"
by (unfold st_def, auto)
lemma stimes_left_commute:
"(q * (p * r)) = ((p::'a set set) * (q * r))"
by (metis stimes_assoc stimes_comm)
lemmas stimes_ac = stimes_comm stimes_assoc stimes_left_commute
lemma "x * y * z = z * y * (x::'a set set)"
by (metis stimes_ac)
definition pasrt :: "bool \<Rightarrow> ('a set set)" ("<_>" [71] 71)
where "pasrt b = {s . s = {} \<and> b}"
datatype apg =
Instr abc_inst
| Label nat
| Seq apg apg
| Local "(nat \<Rightarrow> apg)"
abbreviation prog_instr :: "abc_inst \<Rightarrow> apg" ("\<guillemotright>_" [61] 61)
where "\<guillemotright>i \<equiv> Instr i"
abbreviation prog_seq :: "apg \<Rightarrow> apg \<Rightarrow> apg" (infixr ";" 52)
where "c1 ; c2 \<equiv> Seq c1 c2"
type_synonym aconf = "((nat \<rightharpoonup> abc_inst) \<times> nat \<times> (nat \<rightharpoonup> nat) \<times> nat)"
fun astep :: "aconf \<Rightarrow> aconf"
where "astep (prog, pc, m, faults) =
(case (prog pc) of
Some (Inc i) \<Rightarrow>
case m(i) of
Some n \<Rightarrow> (prog, pc + 1, m(i:= Some (n + 1)), faults)
| None \<Rightarrow> (prog, pc, m, faults + 1)
| Some (Dec i e) \<Rightarrow>
case m(i) of
Some n \<Rightarrow> if (n = 0) then (prog, e, m, faults)
else (prog, pc + 1, m(i:= Some (n - 1)), faults)
| None \<Rightarrow> (prog, pc, m, faults + 1)
| Some (Goto pc') \<Rightarrow> (prog, pc', m, faults)
| None \<Rightarrow> (prog, pc, m, faults + 1))"
definition "run n = astep ^^ n"
datatype aresource =
M nat nat
| C nat abc_inst
| At nat
| Faults nat
definition "prog_set prog = {C i inst | i inst. prog i = Some inst}"
definition "pc_set pc = {At pc}"
definition "mem_set m = {M i n | i n. m (i) = Some n} "
definition "faults_set faults = {Faults faults}"
lemmas cpn_set_def = prog_set_def pc_set_def mem_set_def faults_set_def
fun rset_of :: "aconf \<Rightarrow> aresource set"
where "rset_of (prog, pc, m, faults) =
prog_set prog \<union> pc_set pc \<union> mem_set m \<union> faults_set faults"
definition "pc l = {pc_set l}"
definition "m a v = {{M a v}}"
declare rset_of.simps[simp del]
type_synonym assert = "aresource set set"
primrec assemble_to :: "apg \<Rightarrow> nat \<Rightarrow> nat \<Rightarrow> assert"
where
"assemble_to (Instr ai) i j = ({{C i ai}} * <(j = i + 1)>)" |
"assemble_to (Seq p1 p2) i j = (\<Union> j'. (assemble_to p1 i j') * (assemble_to p2 j' j))" |
"assemble_to (Local fp) i j = (\<Union> l. (assemble_to (fp l) i j))" |
"assemble_to (Label l) i j = <(i = j \<and> j = l)>"
abbreviation asmb_to :: "nat \<Rightarrow> apg \<Rightarrow> nat \<Rightarrow> assert" ("_ :[ _ ]: _" [60, 60, 60] 60)
where "i :[ apg ]: j \<equiv> assemble_to apg i j"
lemma stimes_sgD: "s \<in> {x} * q \<Longrightarrow> (s - x) \<in> q \<and> x \<subseteq> s"
apply (unfold st_def, auto)
by (smt Diff_disjoint Un_Diff_cancel2 Un_Int_distrib
Un_commute Un_empty_right Un_left_absorb)
lemma pcD: "rset_of (prog, i', mem, fault) \<in> pc i * r
\<Longrightarrow> i' = i"
proof -
assume "rset_of (prog, i', mem, fault) \<in> pc i * r"
from stimes_sgD [OF this[unfolded pc_def], unfolded rset_of.simps]
have "pc_set i \<subseteq> prog_set prog \<union> pc_set i' \<union> mem_set mem \<union> faults_set fault" by auto
thus ?thesis
by (unfold cpn_set_def, auto)
qed
lemma codeD: "rset_of (prog, pos, mem, fault) \<in> pc i * {{C i inst}} * r
\<Longrightarrow> prog pos = Some inst"
proof -
assume h: "rset_of (prog, pos, mem, fault) \<in> pc i * {{C i inst}} * r" (is "?c \<in> ?X")
from pcD[OF this] have "i = pos" by simp
with h show ?thesis
by (unfold rset_of.simps st_def pc_def prog_set_def
pc_set_def mem_set_def faults_set_def, auto)
qed
lemma memD: "rset_of (prog, pos, mem, fault) \<in> (m a v) * r \<Longrightarrow> mem a = Some v"
proof -
assume "rset_of (prog, pos, mem, fault) \<in> (m a v) * r"
from stimes_sgD[OF this[unfolded rset_of.simps cpn_set_def m_def]]
have "{M a v} \<subseteq> {C i inst |i inst. prog i = Some inst} \<union>
{At pos} \<union> {M i n |i n. mem i = Some n} \<union> {Faults fault}" by auto
thus ?thesis by auto
qed
definition
Hoare_abc :: "assert \<Rightarrow> assert \<Rightarrow> assert \<Rightarrow> bool" ("({(1_)}/ (_)/ {(1_)})" 50)
where
"{p} c {q} \<equiv> (\<forall> s r. (rset_of s) \<in> (p*c*r) \<longrightarrow>
(\<exists> k. ((rset_of (run k s)) \<in> (q*c*r))))"
definition "dec_fun v j e = (if (v = 0) then (e, v) else (j, v - 1))"
lemma disj_Diff: "a \<inter> b = {} \<Longrightarrow> a \<union> b - b = a"
by (metis (lifting) Diff_cancel Un_Diff Un_Diff_Int)
lemma diff_pc_set: "prog_set aa \<union> pc_set i \<union> mem_set ab \<union> faults_set b - pc_set i =
prog_set aa \<union> mem_set ab \<union> faults_set b" (is "?L = ?R")
proof -
have "?L = (prog_set aa \<union> mem_set ab \<union> faults_set b \<union> pc_set i) - pc_set i"
by auto
also have "\<dots> = ?R"
proof(rule disj_Diff)
show " (prog_set aa \<union> mem_set ab \<union> faults_set b) \<inter> pc_set i = {}"
by (unfold cpn_set_def, auto)
qed
finally show ?thesis .
qed
lemma M_in_simp: "({M a v} \<subseteq> prog_set x \<union> pc_set y \<union> mem_set mem \<union> faults_set f) =
({M a v} \<subseteq> mem_set mem)"
by (unfold cpn_set_def, auto)
lemma mem_set_upd:
"{M a v} \<subseteq> mem_set mem \<Longrightarrow> mem_set (mem(a:=Some v')) = ((mem_set mem) - {M a v}) \<union> {M a v'}"
by (unfold cpn_set_def, auto)
lemma mem_set_disj: "{M a v} \<subseteq> mem_set mem \<Longrightarrow> {M a v'} \<inter> (mem_set mem - {M a v}) = {}"
by (unfold cpn_set_def, auto)
lemma stimesE:
assumes h: "s \<in> x * y"
obtains s1 s2 where "s = s1 \<union> s2" and "s1 \<inter> s2 = {}" and "s1 \<in> x" and "s2 \<in> y"
by (insert h, auto simp:st_def)
lemma stimesI:
"\<lbrakk>s = s1 \<union> s2; s1 \<inter> s2 = {}; s1 \<in> x; s2 \<in> y\<rbrakk> \<Longrightarrow> s \<in> x * y"
by (auto simp:st_def)
lemma smem_upd: "(rset_of (x, y, mem, f)) \<in> (m a v)*r \<Longrightarrow>
(rset_of (x, y, mem(a := Some v'), f) \<in> (m a v')*r)"
proof -
assume h: " rset_of (x, y, mem, f) \<in> m a v * r"
from h[unfolded rset_of.simps m_def]
have "prog_set x \<union> pc_set y \<union> mem_set mem \<union> faults_set f \<in> {{M a v}} * r" .
from stimes_sgD [OF this]
have h1: "prog_set x \<union> pc_set y \<union> mem_set mem \<union> faults_set f - {M a v} \<in> r"
"{M a v} \<subseteq> prog_set x \<union> pc_set y \<union> mem_set mem \<union> faults_set f" by auto
moreover have "prog_set x \<union> pc_set y \<union> mem_set mem \<union> faults_set f - {M a v} =
prog_set x \<union> pc_set y \<union> (mem_set mem - {M a v}) \<union> faults_set f"
by (unfold cpn_set_def, auto)
ultimately have h0: "prog_set x \<union> pc_set y \<union> (mem_set mem - {M a v}) \<union> faults_set f \<in> r"
by simp
from h1(2) and M_in_simp have "{M a v} \<subseteq> mem_set mem" by simp
from mem_set_upd [OF this] mem_set_disj[OF this]
have h2: "mem_set (mem(a \<mapsto> v')) = {M a v'} \<union> (mem_set mem - {M a v})"
"{M a v'} \<inter> (mem_set mem - {M a v}) = {}" by auto
show ?thesis
proof -
have "mem_set (mem(a \<mapsto> v')) \<union> prog_set x \<union> pc_set y \<union> faults_set f \<in> m a v' * r"
proof(rule stimesI[OF _ _ _ h0])
show "{M a v'} \<in> m a v'" by (unfold m_def, auto)
next
show "mem_set (mem(a \<mapsto> v')) \<union> prog_set x \<union> pc_set y \<union> faults_set f =
{M a v'} \<union> (prog_set x \<union> pc_set y \<union> (mem_set mem - {M a v}) \<union> faults_set f)"
apply (unfold h2(1))
by (smt Un_commute Un_insert_left Un_insert_right
Un_left_commute
`prog_set x \<union> pc_set y \<union> mem_set mem \<union>
faults_set f - {M a v} =prog_set x \<union> pc_set y
\<union> (mem_set mem - {M a v}) \<union> faults_set f`)
next
from h2(2)
show "{M a v'} \<inter> (prog_set x \<union> pc_set y \<union> (mem_set mem - {M a v}) \<union> faults_set f) = {}"
by (unfold cpn_set_def, auto)
qed
thus ?thesis
apply (unfold rset_of.simps)
by (metis `mem_set (mem(a \<mapsto> v'))
\<union> prog_set x \<union> pc_set y \<union> faults_set f \<in> m a v' * r`
stimes_comm sup_commute sup_left_commute)
qed
qed
lemma spc_upd: "rset_of (x, i, y, z) \<in> pc i' * r \<Longrightarrow>
rset_of (x, i'', y, z) \<in> pc i'' * r"
proof -
assume h: "rset_of (x, i, y, z) \<in> pc i' * r"
from stimes_sgD [OF h[unfolded rset_of.simps pc_set_def pc_def]]
have h1: "prog_set x \<union> {At i} \<union> mem_set y \<union> faults_set z - {At i'} \<in> r"
"{At i'} \<subseteq> prog_set x \<union> {At i} \<union> mem_set y \<union> faults_set z" by auto
from h1(2) have eq_i: "i' = i" by (unfold cpn_set_def, auto)
have "prog_set x \<union> {At i} \<union> mem_set y \<union> faults_set z - {At i'} =
prog_set x \<union> mem_set y \<union> faults_set z "
apply (unfold eq_i)
by (metis (full_types) Un_insert_left Un_insert_right
diff_pc_set faults_set_def insert_commute insert_is_Un
pc_set_def sup_assoc sup_bot_left sup_commute)
with h1(1) have in_r: "prog_set x \<union> mem_set y \<union> faults_set z \<in> r" by auto
show ?thesis
proof(unfold rset_of.simps, rule stimesI[OF _ _ _ in_r])
show "{At i''} \<in> pc i''" by (unfold pc_def pc_set_def, simp)
next
show "prog_set x \<union> pc_set i'' \<union> mem_set y \<union> faults_set z =
{At i''} \<union> (prog_set x \<union> mem_set y \<union> faults_set z)"
by (unfold pc_set_def, auto)
next
show "{At i''} \<inter> (prog_set x \<union> mem_set y \<union> faults_set z) = {}"
by (auto simp:cpn_set_def)
qed
qed
lemma condD: "s \<in> <b>*r \<Longrightarrow> b"
by (unfold st_def pasrt_def, auto)
lemma condD1: "s \<in> <b>*r \<Longrightarrow> s \<in> r"
by (unfold st_def pasrt_def, auto)
lemma hoare_dec_suc: "{(pc i * m a v) * <(v > 0)>}
i:[\<guillemotright>(Dec a e) ]:j
{pc j * m a (v - 1)}"
proof(unfold Hoare_abc_def, clarify)
fix prog i' ab b r
assume h: "rset_of (prog, i', ab, b) \<in> ((pc i * m a v) * <(0 < v)>) * (i :[ \<guillemotright>Dec a e ]: j) * r"
(is "?r \<in> ?S")
show "\<exists>k. rset_of (run k (prog, i', ab, b)) \<in> (pc j * m a (v - 1)) * (i :[ \<guillemotright>Dec a e ]: j) * r"
proof -
from h [unfolded assemble_to.simps]
have h1: "?r \<in> pc i * {{C i (Dec a e)}} * m a v * <(0 < v)> * <(j = i + 1)> * r"
"?r \<in> m a v * pc i * {{C i (Dec a e)}} * <(0 < v)> * <(j = i + 1)> * r"
"?r \<in> <(0 < v)> * <(j = i + 1)> * m a v * pc i * {{C i (Dec a e)}} * r"
"?r \<in> <(j = i + 1)> * <(0 < v)> * m a v * pc i * {{C i (Dec a e)}} * r"
by ((metis stimes_ac)+)
note h2 = condD [OF h1(3)] condD[OF h1(4)] pcD[OF h1(1)] codeD[OF h1(1)] memD[OF h1(2)]
hence stp: "run 1 (prog, i', ab, b) = (prog, Suc i, ab(a \<mapsto> v - Suc 0), b)" (is "?x = ?y")
by (unfold run_def, auto)
have "rset_of ?x \<in> (pc j * m a (v - 1)) * (i :[ \<guillemotright>Dec a e ]: j) * r"
proof -
have "rset_of ?y \<in> (pc j * m a (v - 1)) * (i :[ \<guillemotright>Dec a e ]: j) * r"
proof -
from spc_upd[OF h1(1), of "Suc i"]
have "rset_of (prog, (Suc i), ab, b) \<in>
m a v * pc (Suc i) * {{C i (Dec a e)}} * <(0 < v)> * <(j = i + 1)> * r"
by (metis stimes_ac)
from smem_upd[OF this, of "v - (Suc 0)"]
have "rset_of ?y \<in>
m a (v - Suc 0) * pc (Suc i) * {{C i (Dec a e)}} * <(0 < v)> * <(j = i + 1)> * r" .
hence "rset_of ?y \<in> <(0 < v)> *
(pc (Suc i) * m a (v - Suc 0)) * ({{C i (Dec a e)}} * <(j = i + 1)>) * r"
by (metis stimes_ac)
from condD1[OF this]
have "rset_of ?y \<in> (pc (Suc i) * m a (v - Suc 0)) * ({{C i (Dec a e)}} * <(j = i + 1)>) * r" .
thus ?thesis
by (unfold h2(2) assemble_to.simps, simp)
qed
with stp show ?thesis by simp
qed
thus ?thesis by blast
qed
qed
lemma hoare_dec_fail: "{pc i * m a 0}
i:[ \<guillemotright>(Dec a e) ]:j
{pc e * m a 0}"
proof(unfold Hoare_abc_def, clarify)
fix prog i' ab b r
assume h: "rset_of (prog, i', ab, b) \<in> (pc i * m a 0) * (i :[ \<guillemotright>Dec a e ]: j) * r"
(is "?r \<in> ?S")
show "\<exists>k. rset_of (run k (prog, i', ab, b)) \<in> (pc e * m a 0) * (i :[ \<guillemotright>Dec a e ]: j) * r"
proof -
from h [unfolded assemble_to.simps]
have h1: "?r \<in> pc i * {{C i (Dec a e)}} * m a 0 * <(j = i + 1)> * r"
"?r \<in> m a 0 * pc i * {{C i (Dec a e)}} * <(j = i + 1)> * r"
"?r \<in> <(j = i + 1)> * m a 0 * pc i * {{C i (Dec a e)}} * r"
by ((metis stimes_ac)+)
note h2 = condD [OF h1(3)] pcD[OF h1(1)] codeD[OF h1(1)] memD[OF h1(2)]
hence stp: "run 1 (prog, i', ab, b) = (prog, e, ab, b)" (is "?x = ?y")
by (unfold run_def, auto)
have "rset_of ?x \<in> (pc e * m a 0) * (i :[ \<guillemotright>Dec a e ]: j) * r"
proof -
have "rset_of ?y \<in> (pc e * m a 0) * (i :[ \<guillemotright>Dec a e ]: j) * r"
proof -
from spc_upd[OF h1(1), of "e"]
have "rset_of ?y \<in> pc e * {{C i (Dec a e)}} * m a 0 * <(j = i + 1)> * r" .
thus ?thesis
by (unfold assemble_to.simps, metis stimes_ac)
qed
with stp show ?thesis by simp
qed
thus ?thesis by blast
qed
qed
lemma pasrtD_p: "\<lbrakk>{p*<b>} c {q}\<rbrakk> \<Longrightarrow> (b \<longrightarrow> {p} c {q})"
apply (unfold Hoare_abc_def pasrt_def, auto)
by (fold emp_def, simp add:emp_unit_r)
lemma hoare_dec: "dec_fun v j e = (pc', v') \<Longrightarrow>
{pc i * m a v}
i:[ \<guillemotright>(Dec a e) ]:j
{pc pc' * m a v'}"
proof -
assume "dec_fun v j e = (pc', v')"
thus "{pc i * m a v}
i:[ \<guillemotright>(Dec a e) ]:j
{pc pc' * m a v'}"
apply (auto split:if_splits simp:dec_fun_def)
apply (insert hoare_dec_fail, auto)[1]
apply (insert hoare_dec_suc, auto)
apply (atomize)
apply (erule_tac x = i in allE, erule_tac x = a in allE,
erule_tac x = v in allE, erule_tac x = e in allE, erule_tac x = pc' in allE)
by (drule_tac pasrtD_p, clarify)
qed
lemma hoare_inc: "{pc i * m a v}
i:[ \<guillemotright>(Inc a) ]:j
{pc j * m a (v + 1)}"
proof(unfold Hoare_abc_def, clarify)
fix prog i' ab b r
assume h: "rset_of (prog, i', ab, b) \<in> (pc i * m a v) * (i :[ \<guillemotright>Inc a ]: j) * r"
(is "?r \<in> ?S")
show "\<exists>k. rset_of (run k (prog, i', ab, b)) \<in> (pc j * m a (v + 1)) * (i :[ \<guillemotright>Inc a ]: j) * r"
proof -
from h [unfolded assemble_to.simps]
have h1: "?r \<in> pc i * {{C i (Inc a)}} * m a v * <(j = i + 1)> * r"
"?r \<in> m a v * pc i * {{C i (Inc a)}} * <(j = i + 1)> * r"
"?r \<in> <(j = i + 1)> * m a v * pc i * {{C i (Inc a)}} * r"
by ((metis stimes_ac)+)
note h2 = condD [OF h1(3)] pcD[OF h1(1)] codeD[OF h1(1)] memD[OF h1(2)]
hence stp: "run 1 (prog, i', ab, b) = (prog, Suc i, ab(a \<mapsto> Suc v), b)" (is "?x = ?y")
by (unfold run_def, auto)
have "rset_of ?x \<in> (pc j * m a (v + 1)) * (i :[ \<guillemotright>Inc a]: j) * r"
proof -
have "rset_of ?y \<in> (pc j * m a (v + 1)) * (i :[ \<guillemotright>Inc a ]: j) * r"
proof -
from spc_upd[OF h1(1), of "Suc i"]
have "rset_of (prog, (Suc i), ab, b) \<in>
m a v * pc (Suc i) * {{C i (Inc a)}} * <(j = i + 1)> * r"
by (metis stimes_ac)
from smem_upd[OF this, of "Suc v"]
have "rset_of ?y \<in>
m a (v + 1) * pc (i + 1) * {{C i (Inc a)}} * <(j = i + 1)> * r" by simp
thus ?thesis
by (unfold h2(1) assemble_to.simps, metis stimes_ac)
qed
with stp show ?thesis by simp
qed
thus ?thesis by blast
qed
qed
lemma hoare_goto: "{pc i}
i:[ \<guillemotright>(Goto e) ]:j
{pc e}"
proof(unfold Hoare_abc_def, clarify)
fix prog i' ab b r
assume h: "rset_of (prog, i', ab, b) \<in> pc i * (i :[ \<guillemotright>Goto e ]: j) * r"
(is "?r \<in> ?S")
show "\<exists>k. rset_of (run k (prog, i', ab, b)) \<in> pc e * (i :[ \<guillemotright>Goto e ]: j) * r"
proof -
from h [unfolded assemble_to.simps]
have h1: "?r \<in> pc i * {{C i (Goto e)}} * <(j = i + 1)> * r"
by ((metis stimes_ac)+)
note h2 = pcD[OF h1(1)] codeD[OF h1(1)]
hence stp: "run 1 (prog, i', ab, b) = (prog, e, ab, b)" (is "?x = ?y")
by (unfold run_def, auto)
have "rset_of ?x \<in> pc e * (i :[ \<guillemotright>Goto e]: j) * r"
proof -
from spc_upd[OF h1(1), of "e"]
show ?thesis
by (unfold stp assemble_to.simps, metis stimes_ac)
qed
thus ?thesis by blast
qed
qed
no_notation stimes (infixr "*" 70)
interpretation foo: comm_monoid_mult
"stimes :: 'a set set => 'a set set => 'a set set" "emp::'a set set"
apply(default)
apply(simp add: stimes_assoc)
apply(simp add: stimes_comm)
apply(simp add: emp_def[symmetric])
done
notation stimes (infixr "*" 70)
(*used by simplifier for numbers *)
thm mult_cancel_left
(*
interpretation foo: comm_ring_1 "op * :: 'a set set => 'a set set => 'a set set" "{{}}::'a set set"
apply(default)
*)
lemma frame: "{p} c {q} \<Longrightarrow> \<forall> r. {p * r} c {q * r}"
apply (unfold Hoare_abc_def, clarify)
apply (erule_tac x = "(a, aa, ab, b)" in allE)
apply (erule_tac x = "r * ra" in allE)
apply(metis stimes_ac)
done
lemma code_extension: "\<lbrakk>{p} c {q}\<rbrakk> \<Longrightarrow> (\<forall> e. {p} c * e {q})"
apply (unfold Hoare_abc_def, clarify)
apply (erule_tac x = "(a, aa, ab, b)" in allE)
apply (erule_tac x = "e * r" in allE)
apply(metis stimes_ac)
done
lemma run_add: "run (n1 + n2) s = run n1 (run n2 s)"
apply (unfold run_def)
by (metis funpow_add o_apply)
lemma composition: "\<lbrakk>{p} c1 {q}; {q} c2 {r}\<rbrakk> \<Longrightarrow> {p} c1 * c2 {r}"
proof -
assume h: "{p} c1 {q}" "{q} c2 {r}"
from code_extension [OF h(1), rule_format, of "c2"]
have "{p} c1 * c2 {q}" .
moreover from code_extension [OF h(2), rule_format, of "c1"] and stimes_comm
have "{q} c1 * c2 {r}" by metis
ultimately show "{p} c1 * c2 {r}"
apply (unfold Hoare_abc_def, clarify)
proof -
fix a aa ab b ra
assume h1: "\<forall>s r. rset_of s \<in> p * (c1 * c2) * r \<longrightarrow>
(\<exists>k. rset_of (run k s) \<in> q * (c1 * c2) * r)"
and h2: "\<forall>s ra. rset_of s \<in> q * (c1 * c2) * ra \<longrightarrow>
(\<exists>k. rset_of (run k s) \<in> r * (c1 * c2) * ra)"
and h3: "rset_of (a, aa, ab, b) \<in> p * (c1 * c2) * ra"
show "\<exists>k. rset_of (run k (a, aa, ab, b)) \<in> r * (c1 * c2) * ra"
proof -
let ?s = "(a, aa, ab, b)"
from h1 [rule_format, of ?s, OF h3]
obtain n1 where "rset_of (run n1 ?s) \<in> q * (c1 * c2) * ra" by blast
from h2 [rule_format, OF this]
obtain n2 where "rset_of (run n2 (run n1 ?s)) \<in> r * (c1 * c2) * ra" by blast
with run_add show ?thesis by metis
qed
qed
qed
lemma stimes_simp: "s \<in> x * y = (\<exists> s1 s2. (s = s1 \<union> s2 \<and> s1 \<inter> s2 = {} \<and> s1 \<in> x \<and> s2 \<in> y))"
by (metis (lifting) stimesE stimesI)
lemma hoare_seq:
"\<lbrakk>\<forall> i j. {pc i * p} i:[c1]:j {pc j * q};
\<forall> j k. {pc j * q} j:[c2]:k {pc k * r}\<rbrakk> \<Longrightarrow> {pc i * p} i:[(c1 ; c2)]:k {pc k *r}"
proof -
assume h: "\<forall>i j. {pc i * p} i :[ c1 ]: j {pc j * q}" "\<forall> j k. {pc j * q} j:[c2]:k {pc k * r}"
show "{pc i * p} i:[(c1 ; c2)]:k {pc k *r}"
proof(subst Hoare_abc_def, clarify)
fix a aa ab b ra
assume "rset_of (a, aa, ab, b) \<in> (pc i * p) * (i :[ (c1 ; c2) ]: k) * ra"
hence "rset_of (a, aa, ab, b) \<in> (i :[ (c1 ; c2) ]: k) * (pc i * p * ra)" (is "?s \<in> ?X * ?Y")
by (metis stimes_ac)
from stimesE[OF this] obtain s1 s2 where
sp: "rset_of(a, aa, ab, b) = s1 \<union> s2" "s1 \<inter> s2 = {}" "s1 \<in> ?X" "s2 \<in> ?Y" by blast
from sp (3) obtain j' where
"s1 \<in> (i:[c1]:j') * (j':[c2]:k)" (is "s1 \<in> ?Z")
by (auto simp:assemble_to.simps)
from stimesI[OF sp(1, 2) this sp(4)]
have "?s \<in> (pc i * p) * (i :[ c1 ]: j') * (j' :[ c2 ]: k) * ra" by (metis stimes_ac)
from h(1)[unfolded Hoare_abc_def, rule_format, OF this]
obtain ka where
"rset_of (run ka (a, aa, ab, b)) \<in> (pc j' * q) * (j' :[ c2 ]: k) * ((i :[ c1 ]: j') * ra)"
sorry
from h(2)[unfolded Hoare_abc_def, rule_format, OF this]
obtain kb where
"rset_of (run kb (run ka (a, aa, ab, b)))
\<in> (pc k * r) * (j' :[ c2 ]: k) * (i :[ c1 ]: j') * ra" by blast
hence h3: "rset_of (run (kb + ka) (a, aa, ab, b))
\<in> pc k * r * (j' :[ c2 ]: k) * ((i :[ c1 ]: j') * ra)"
sorry
hence "rset_of (run (kb + ka) (a, aa, ab, b)) \<in> pc k * r * (i :[ (c1 ; c2) ]: k) * ra"
proof -
have "rset_of (run (kb + ka) (a, aa, ab, b)) \<in> (i :[ (c1 ; c2) ]: k) * (pc k * r * ra)"
proof -
from h3 have "rset_of (run (kb + ka) (a, aa, ab, b))
\<in> ((j' :[ c2 ]: k) * ((i :[ c1 ]: j'))) * (pc k * r * ra)"
by (metis stimes_ac)
then obtain
s1 s2 where h4: "rset_of (run (kb + ka) (a, aa, ab, b)) = s1 \<union> s2"
" s1 \<inter> s2 = {}" "s1 \<in> (j' :[ c2 ]: k) * (i :[ c1 ]: j')"
"s2 \<in> pc k * r * ra" by (rule stimesE, blast)
from h4(3) have "s1 \<in> (i :[ (c1 ; c2) ]: k)"
sorry
from stimesI [OF h4(1, 2) this h4(4)]
show ?thesis .
qed
thus ?thesis by (metis stimes_ac)
qed
thus "\<exists>ka. rset_of (run ka (a, aa, ab, b)) \<in> (pc k * r) * (i :[ (c1 ; c2) ]: k) * ra"
by (metis stimes_ac)
qed
qed
lemma hoare_local:
"\<forall> l i j. {pc i*p} i:[c(l)]:j {pc j * q}
\<Longrightarrow> {pc i * p} i:[Local c]:j {pc j * q}"
proof -
assume h: "\<forall> l i j. {pc i*p} i:[c(l)]:j {pc j * q} "
show "{pc i * p} i:[Local c]:j {pc j * q}"
proof(unfold assemble_to.simps Hoare_abc_def, clarify)
fix a aa ab b r
assume h1: "rset_of (a, aa, ab, b) \<in> (pc i * p) * (\<Union>l. i :[ c l ]: j) * r"
hence "rset_of (a, aa, ab, b) \<in> (\<Union>l. i :[ c l ]: j) * (pc i * p * r)"
by (metis stimes_ac)
then obtain s1 s2 l
where "rset_of (a, aa, ab, b) = s1 \<union> s2"
"s1 \<inter> s2 = {}"
"s1 \<in> (i :[ c l ]: j)"
"s2 \<in> pc i * p * r"
by (rule stimesE, auto)
from stimesI[OF this]
have "rset_of (a, aa, ab, b) \<in> (pc i * p) * (i :[ c l ]: j) * r"
by (metis stimes_ac)
from h[unfolded Hoare_abc_def, rule_format, OF this]
obtain k where "rset_of (run k (a, aa, ab, b)) \<in> (i :[ c l ]: j) * (pc j * q * r)"
sorry
then obtain s1 s2
where h3: "rset_of (run k (a, aa, ab, b)) = s1 \<union> s2"
" s1 \<inter> s2 = {}" "s1 \<in> (\<Union> l. (i :[ c l ]: j))" "s2 \<in> pc j * q * r"
by(rule stimesE, auto)
from stimesI[OF this]
show "\<exists>k. rset_of (run k (a, aa, ab, b)) \<in> (pc j * q) * (\<Union>l. i :[ c l ]: j) * r"
by (metis stimes_ac)
qed
qed
lemma move_pure: "{p*<b>} c {q} = (b \<longrightarrow> {p} c {q})"
proof(unfold Hoare_abc_def, default, clarify)
fix prog i' mem ft r
assume h: "\<forall>s r. rset_of s \<in> (p * <b>) * c * r \<longrightarrow> (\<exists>k. rset_of (run k s) \<in> q * c * r)"
"b" "rset_of (prog, i', mem, ft) \<in> p * c * r"
show "\<exists>k. rset_of (run k (prog, i', mem, ft)) \<in> q * c * r"
proof(rule h(1)[rule_format])
have "(p * <b>) * c * r = <b> * p * c * r" by (metis stimes_ac)
moreover have "rset_of (prog, i', mem, ft) \<in> \<dots>"
proof(rule stimesI[OF _ _ _ h(3)])
from h(2) show "{} \<in> <b>" by (auto simp:pasrt_def)
qed auto
ultimately show "rset_of (prog, i', mem, ft) \<in> (p * <b>) * c * r"
by (simp)
qed
next
assume h: "b \<longrightarrow> (\<forall>s r. rset_of s \<in> p * c * r \<longrightarrow> (\<exists>k. rset_of (run k s) \<in> q * c * r))"
show "\<forall>s r. rset_of s \<in> (p * <b>) * c * r \<longrightarrow> (\<exists>k. rset_of (run k s) \<in> q * c * r)"
proof -
{ fix s r
assume "rset_of s \<in> (p * <b>) * c * r"
hence h1: "rset_of s \<in> <b> * p * c * r" by (metis stimes_ac)
have "(\<exists>k. rset_of (run k s) \<in> q * c * r)"
proof(rule h[rule_format])
from condD[OF h1] show b .
next
from condD1[OF h1] show "rset_of s \<in> p * c * r" .
qed
} thus ?thesis by blast
qed
qed
lemma precond_ex: "{\<Union> x. p x} c {q} = (\<forall> x. {p x} c {q})"
proof(unfold Hoare_abc_def, default, clarify)
fix x prog i' mem ft r
assume h: "\<forall>s r. rset_of s \<in> UNION UNIV p * c * r \<longrightarrow> (\<exists>k. rset_of (run k s) \<in> q * c * r)"
"rset_of (prog, i', mem, ft) \<in> p x * c * r"
show "\<exists>k. rset_of (run k (prog, i', mem, ft)) \<in> q * c * r"
proof(rule h[rule_format])
from h(2) show "rset_of (prog, i', mem, ft) \<in> UNION UNIV p * c * r" by (auto simp:stimes_def)
qed
next
assume h: "\<forall>x s r. rset_of s \<in> p x * c * r \<longrightarrow> (\<exists>k. rset_of (run k s) \<in> q * c * r)"
show "\<forall>s r. rset_of s \<in> UNION UNIV p * c * r \<longrightarrow> (\<exists>k. rset_of (run k s) \<in> q * c * r)"
proof -
{ fix s r
assume "rset_of s \<in> UNION UNIV p * c * r"
then obtain x where "rset_of s \<in> p x * c * r"
by (unfold st_def, auto, metis)
hence "(\<exists>k. rset_of (run k s) \<in> q * c * r)"
by(rule h[rule_format])
} thus ?thesis by blast
qed
qed
lemma code_exI: "\<lbrakk>\<And>l. {p} c l * c' {q}\<rbrakk> \<Longrightarrow> {p} (\<Union> l. c l) * c' {q}"
proof(unfold Hoare_abc_def, default, clarify)
fix prog i' mem ft r
assume h: "\<And>l. \<forall>s r. rset_of s \<in> p * (c l * c') * r \<longrightarrow> (\<exists>k. rset_of (run k s) \<in> q * (c l * c') * r)"
"rset_of (prog, i', mem, ft) \<in> p * (UNION UNIV c * c') * r"
show " \<exists>k. rset_of (run k (prog, i', mem, ft)) \<in> q * (UNION UNIV c * c') * r"
proof -
from h(2) obtain l where "rset_of (prog, i', mem, ft) \<in> p * (c l * c') * r"
apply (unfold st_def, auto)
by metis
from h(1)[rule_format, OF this]
obtain k where " rset_of (run k (prog, i', mem, ft)) \<in> q * (c l * c') * r" by blast
thus ?thesis by (unfold st_def, auto, metis)
qed
qed
lemma code_exIe: "\<lbrakk>\<And>l. {p} c l{q}\<rbrakk> \<Longrightarrow> {p} \<Union> l. (c l) {q}"
proof -
assume "\<And>l. {p} c l {q}"
thus "{p} \<Union>l. c l {q}"
by(rule code_exI[where c'= "emp", unfolded emp_unit_r])
qed
lemma pre_stren: "\<lbrakk>{p} c {q}; r \<subseteq> p\<rbrakk> \<Longrightarrow> {r} c {q}"
proof(unfold Hoare_abc_def, clarify)
fix prog i' mem ft r'
assume h: "\<forall>s r. rset_of s \<in> p * c * r \<longrightarrow> (\<exists>k. rset_of (run k s) \<in> q * c * r)"
" r \<subseteq> p" " rset_of (prog, i', mem, ft) \<in> r * c * r'"
show "\<exists>k. rset_of (run k (prog, i', mem, ft)) \<in> q * c * r'"
proof(rule h(1)[rule_format])
from stimes_mono[OF h(2), of "c * r'"] h(3)
show "rset_of (prog, i', mem, ft) \<in> p * c * r'" by auto
qed
qed
lemma post_weaken: "\<lbrakk>{p} c {q}; q \<subseteq> r\<rbrakk> \<Longrightarrow> {p} c {r}"
proof(unfold Hoare_abc_def, clarify)
fix prog i' mem ft r'
assume h: "\<forall>s r. rset_of s \<in> p * c * r \<longrightarrow> (\<exists>k. rset_of (run k s) \<in> q * c * r)"
" q \<subseteq> r" "rset_of (prog, i', mem, ft) \<in> p * c * r'"
show "\<exists>k. rset_of (run k (prog, i', mem, ft)) \<in> r * c * r'"
proof -
from h(1)[rule_format, OF h(3)]
obtain k where "rset_of (run k (prog, i', mem, ft)) \<in> q * c * r'" by auto
moreover from h(2) have "\<dots> \<subseteq> r * c * r'" by (metis stimes_mono)
ultimately show ?thesis by auto
qed
qed
definition "clear a =
Local (\<lambda> start. (Local (\<lambda> exit. Label start; \<guillemotright>Dec a exit; \<guillemotright> Goto start; Label exit)))"
lemma "{pc i * m a v} i:[clear a]:j {pc j*m a 0}"
proof (unfold clear_def, rule hoare_local, default+)
fix l i j
show "{pc i * m a v} i :[ Local (\<lambda>exit. Label l ; \<guillemotright>Dec a exit ; \<guillemotright>Goto l ; Label exit) ]: j
{pc j * m a 0}"
proof(rule hoare_local, default+)
fix la i j
show "{pc i * m a v} i :[ (Label l ; \<guillemotright>Dec a la ; \<guillemotright>Goto l ; Label la) ]: j {pc j * m a 0}"
proof(subst assemble_to.simps, rule code_exIe)
have "\<And>j'. {pc i * m a v} (j' :[ (\<guillemotright>Dec a la ; \<guillemotright>Goto l ; Label la) ]: j) * (i :[ Label l ]: j')
{pc j * m a 0}"
proof(subst assemble_to.simps, rule code_exI)
fix j' j'a
show "{pc i * m a v}
((j' :[ \<guillemotright>Dec a la ]: j'a) * (j'a :[ (\<guillemotright>Goto l ; Label la) ]: j)) * (i :[ Label l ]: j')
{pc j * m a 0}"
proof(unfold assemble_to.simps)
have "{pc i * m a v}
((\<Union>j'. ({{C j'a (Goto l)}} * <(j' = j'a + 1)>) * ({{C j' (Dec a la)}} * <(j'a = j' + 1)>)
* <(j' = j \<and> j = la)>)) *
<(i = j' \<and> j' = l)>
{pc j * m a 0}"
proof(rule code_exI, fold assemble_to.simps)
qed
thus "{pc i * m a v}
(({{C j' (Dec a la)}} * <(j'a = j' + 1)>) *
(\<Union>j'. ({{C j'a (Goto l)}} * <(j' = j'a + 1)>) * <(j' = j \<and> j = la)>)) *
<(i = j' \<and> j' = l)>
{pc j * m a 0}" sorry
qed
qed
thus "\<And>j'. {pc i * m a v} (i :[ Label l ]: j') * (j' :[ (\<guillemotright>Dec a la ; \<guillemotright>Goto l ; Label la) ]: j)
{pc j * m a 0}" by (metis stimes_ac)
qed
qed
qed
end