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(* Title: HOLCF/ex/Pattern_Match.thy
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Author: Brian Huffman
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*)
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header {* An experimental pattern-matching notation *}
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theory Pattern_Match
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imports HOLCF
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begin
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text {* FIXME: Find a proper way to un-hide constants. *}
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abbreviation fail :: "'a match"
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where "fail \<equiv> Fixrec.fail"
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abbreviation succeed :: "'a \<rightarrow> 'a match"
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where "succeed \<equiv> Fixrec.succeed"
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abbreviation run :: "'a match \<rightarrow> 'a"
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where "run \<equiv> Fixrec.run"
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subsection {* Fatbar combinator *}
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definition
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fatbar :: "('a \<rightarrow> 'b match) \<rightarrow> ('a \<rightarrow> 'b match) \<rightarrow> ('a \<rightarrow> 'b match)" where
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"fatbar = (\<Lambda> a b x. a\<cdot>x +++ b\<cdot>x)"
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abbreviation
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fatbar_syn :: "['a \<rightarrow> 'b match, 'a \<rightarrow> 'b match] \<Rightarrow> 'a \<rightarrow> 'b match" (infixr "\<parallel>" 60) where
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"m1 \<parallel> m2 == fatbar\<cdot>m1\<cdot>m2"
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lemma fatbar1: "m\<cdot>x = \<bottom> \<Longrightarrow> (m \<parallel> ms)\<cdot>x = \<bottom>"
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by (simp add: fatbar_def)
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lemma fatbar2: "m\<cdot>x = fail \<Longrightarrow> (m \<parallel> ms)\<cdot>x = ms\<cdot>x"
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by (simp add: fatbar_def)
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lemma fatbar3: "m\<cdot>x = succeed\<cdot>y \<Longrightarrow> (m \<parallel> ms)\<cdot>x = succeed\<cdot>y"
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by (simp add: fatbar_def)
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lemmas fatbar_simps = fatbar1 fatbar2 fatbar3
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lemma run_fatbar1: "m\<cdot>x = \<bottom> \<Longrightarrow> run\<cdot>((m \<parallel> ms)\<cdot>x) = \<bottom>"
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by (simp add: fatbar_def)
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lemma run_fatbar2: "m\<cdot>x = fail \<Longrightarrow> run\<cdot>((m \<parallel> ms)\<cdot>x) = run\<cdot>(ms\<cdot>x)"
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by (simp add: fatbar_def)
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lemma run_fatbar3: "m\<cdot>x = succeed\<cdot>y \<Longrightarrow> run\<cdot>((m \<parallel> ms)\<cdot>x) = y"
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by (simp add: fatbar_def)
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lemmas run_fatbar_simps [simp] = run_fatbar1 run_fatbar2 run_fatbar3
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subsection {* Case branch combinator *}
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definition
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branch :: "('a \<rightarrow> 'b match) \<Rightarrow> ('b \<rightarrow> 'c) \<rightarrow> ('a \<rightarrow> 'c match)" where
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"branch p \<equiv> \<Lambda> r x. match_case\<cdot>fail\<cdot>(\<Lambda> y. succeed\<cdot>(r\<cdot>y))\<cdot>(p\<cdot>x)"
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lemma branch_simps:
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"p\<cdot>x = \<bottom> \<Longrightarrow> branch p\<cdot>r\<cdot>x = \<bottom>"
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"p\<cdot>x = fail \<Longrightarrow> branch p\<cdot>r\<cdot>x = fail"
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"p\<cdot>x = succeed\<cdot>y \<Longrightarrow> branch p\<cdot>r\<cdot>x = succeed\<cdot>(r\<cdot>y)"
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by (simp_all add: branch_def)
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lemma branch_succeed [simp]: "branch succeed\<cdot>r\<cdot>x = succeed\<cdot>(r\<cdot>x)"
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by (simp add: branch_def)
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subsection {* Cases operator *}
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definition
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cases :: "'a match \<rightarrow> 'a::pcpo" where
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"cases = match_case\<cdot>\<bottom>\<cdot>ID"
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text {* rewrite rules for cases *}
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lemma cases_strict [simp]: "cases\<cdot>\<bottom> = \<bottom>"
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by (simp add: cases_def)
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lemma cases_fail [simp]: "cases\<cdot>fail = \<bottom>"
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by (simp add: cases_def)
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lemma cases_succeed [simp]: "cases\<cdot>(succeed\<cdot>x) = x"
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by (simp add: cases_def)
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subsection {* Case syntax *}
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nonterminals
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Case_syn Cases_syn
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syntax
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"_Case_syntax":: "['a, Cases_syn] => 'b" ("(Case _ of/ _)" 10)
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"_Case1" :: "['a, 'b] => Case_syn" ("(2_ =>/ _)" 10)
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"" :: "Case_syn => Cases_syn" ("_")
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"_Case2" :: "[Case_syn, Cases_syn] => Cases_syn" ("_/ | _")
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syntax (xsymbols)
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"_Case1" :: "['a, 'b] => Case_syn" ("(2_ \<Rightarrow>/ _)" 10)
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translations
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"_Case_syntax x ms" == "CONST cases\<cdot>(ms\<cdot>x)"
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"_Case2 m ms" == "m \<parallel> ms"
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text {* Parsing Case expressions *}
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syntax
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"_pat" :: "'a"
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"_variable" :: "'a"
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"_noargs" :: "'a"
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translations
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"_Case1 p r" => "CONST branch (_pat p)\<cdot>(_variable p r)"
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"_variable (_args x y) r" => "CONST csplit\<cdot>(_variable x (_variable y r))"
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"_variable _noargs r" => "CONST unit_when\<cdot>r"
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parse_translation {*
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(* rewrite (_pat x) => (succeed) *)
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(* rewrite (_variable x t) => (Abs_CFun (%x. t)) *)
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[(@{syntax_const "_pat"}, fn _ => Syntax.const @{const_syntax Fixrec.succeed}),
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mk_binder_tr (@{syntax_const "_variable"}, @{const_syntax Abs_CFun})];
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*}
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text {* Printing Case expressions *}
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syntax
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"_match" :: "'a"
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print_translation {*
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let
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fun dest_LAM (Const (@{const_syntax Rep_CFun},_) $ Const (@{const_syntax unit_when},_) $ t) =
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(Syntax.const @{syntax_const "_noargs"}, t)
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| dest_LAM (Const (@{const_syntax Rep_CFun},_) $ Const (@{const_syntax csplit},_) $ t) =
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let
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val (v1, t1) = dest_LAM t;
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val (v2, t2) = dest_LAM t1;
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in (Syntax.const @{syntax_const "_args"} $ v1 $ v2, t2) end
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| dest_LAM (Const (@{const_syntax Abs_CFun},_) $ t) =
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let
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val abs =
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case t of Abs abs => abs
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| _ => ("x", dummyT, incr_boundvars 1 t $ Bound 0);
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val (x, t') = atomic_abs_tr' abs;
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in (Syntax.const @{syntax_const "_variable"} $ x, t') end
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| dest_LAM _ = raise Match; (* too few vars: abort translation *)
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fun Case1_tr' [Const(@{const_syntax branch},_) $ p, r] =
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let val (v, t) = dest_LAM r in
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Syntax.const @{syntax_const "_Case1"} $
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(Syntax.const @{syntax_const "_match"} $ p $ v) $ t
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end;
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in [(@{const_syntax Rep_CFun}, Case1_tr')] end;
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*}
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translations
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"x" <= "_match (CONST succeed) (_variable x)"
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subsection {* Pattern combinators for data constructors *}
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types ('a, 'b) pat = "'a \<rightarrow> 'b match"
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definition
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cpair_pat :: "('a, 'c) pat \<Rightarrow> ('b, 'd) pat \<Rightarrow> ('a \<times> 'b, 'c \<times> 'd) pat" where
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"cpair_pat p1 p2 = (\<Lambda>(x, y).
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match_case\<cdot>fail\<cdot>(\<Lambda> a. match_case\<cdot>fail\<cdot>(\<Lambda> b. succeed\<cdot>(a, b))\<cdot>(p2\<cdot>y))\<cdot>(p1\<cdot>x))"
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definition
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spair_pat ::
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"('a, 'c) pat \<Rightarrow> ('b, 'd) pat \<Rightarrow> ('a::pcpo \<otimes> 'b::pcpo, 'c \<times> 'd) pat" where
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"spair_pat p1 p2 = (\<Lambda>(:x, y:). cpair_pat p1 p2\<cdot>(x, y))"
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definition
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sinl_pat :: "('a, 'c) pat \<Rightarrow> ('a::pcpo \<oplus> 'b::pcpo, 'c) pat" where
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"sinl_pat p = sscase\<cdot>p\<cdot>(\<Lambda> x. fail)"
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definition
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sinr_pat :: "('b, 'c) pat \<Rightarrow> ('a::pcpo \<oplus> 'b::pcpo, 'c) pat" where
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"sinr_pat p = sscase\<cdot>(\<Lambda> x. fail)\<cdot>p"
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definition
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up_pat :: "('a, 'b) pat \<Rightarrow> ('a u, 'b) pat" where
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"up_pat p = fup\<cdot>p"
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definition
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TT_pat :: "(tr, unit) pat" where
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"TT_pat = (\<Lambda> b. If b then succeed\<cdot>() else fail fi)"
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definition
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FF_pat :: "(tr, unit) pat" where
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"FF_pat = (\<Lambda> b. If b then fail else succeed\<cdot>() fi)"
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definition
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ONE_pat :: "(one, unit) pat" where
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"ONE_pat = (\<Lambda> ONE. succeed\<cdot>())"
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text {* Parse translations (patterns) *}
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translations
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"_pat (XCONST Pair x y)" => "CONST cpair_pat (_pat x) (_pat y)"
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"_pat (XCONST spair\<cdot>x\<cdot>y)" => "CONST spair_pat (_pat x) (_pat y)"
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"_pat (XCONST sinl\<cdot>x)" => "CONST sinl_pat (_pat x)"
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"_pat (XCONST sinr\<cdot>x)" => "CONST sinr_pat (_pat x)"
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"_pat (XCONST up\<cdot>x)" => "CONST up_pat (_pat x)"
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"_pat (XCONST TT)" => "CONST TT_pat"
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"_pat (XCONST FF)" => "CONST FF_pat"
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"_pat (XCONST ONE)" => "CONST ONE_pat"
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text {* CONST version is also needed for constructors with special syntax *}
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translations
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"_pat (CONST Pair x y)" => "CONST cpair_pat (_pat x) (_pat y)"
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"_pat (CONST spair\<cdot>x\<cdot>y)" => "CONST spair_pat (_pat x) (_pat y)"
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text {* Parse translations (variables) *}
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translations
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"_variable (XCONST Pair x y) r" => "_variable (_args x y) r"
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"_variable (XCONST spair\<cdot>x\<cdot>y) r" => "_variable (_args x y) r"
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"_variable (XCONST sinl\<cdot>x) r" => "_variable x r"
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"_variable (XCONST sinr\<cdot>x) r" => "_variable x r"
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"_variable (XCONST up\<cdot>x) r" => "_variable x r"
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"_variable (XCONST TT) r" => "_variable _noargs r"
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"_variable (XCONST FF) r" => "_variable _noargs r"
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"_variable (XCONST ONE) r" => "_variable _noargs r"
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translations
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"_variable (CONST Pair x y) r" => "_variable (_args x y) r"
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"_variable (CONST spair\<cdot>x\<cdot>y) r" => "_variable (_args x y) r"
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text {* Print translations *}
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translations
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"CONST Pair (_match p1 v1) (_match p2 v2)"
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<= "_match (CONST cpair_pat p1 p2) (_args v1 v2)"
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"CONST spair\<cdot>(_match p1 v1)\<cdot>(_match p2 v2)"
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<= "_match (CONST spair_pat p1 p2) (_args v1 v2)"
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"CONST sinl\<cdot>(_match p1 v1)" <= "_match (CONST sinl_pat p1) v1"
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"CONST sinr\<cdot>(_match p1 v1)" <= "_match (CONST sinr_pat p1) v1"
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"CONST up\<cdot>(_match p1 v1)" <= "_match (CONST up_pat p1) v1"
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"CONST TT" <= "_match (CONST TT_pat) _noargs"
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"CONST FF" <= "_match (CONST FF_pat) _noargs"
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"CONST ONE" <= "_match (CONST ONE_pat) _noargs"
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lemma cpair_pat1:
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"branch p\<cdot>r\<cdot>x = \<bottom> \<Longrightarrow> branch (cpair_pat p q)\<cdot>(csplit\<cdot>r)\<cdot>(x, y) = \<bottom>"
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apply (simp add: branch_def cpair_pat_def)
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apply (cases "p\<cdot>x", simp_all)
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done
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lemma cpair_pat2:
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"branch p\<cdot>r\<cdot>x = fail \<Longrightarrow> branch (cpair_pat p q)\<cdot>(csplit\<cdot>r)\<cdot>(x, y) = fail"
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apply (simp add: branch_def cpair_pat_def)
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apply (cases "p\<cdot>x", simp_all)
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done
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lemma cpair_pat3:
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"branch p\<cdot>r\<cdot>x = succeed\<cdot>s \<Longrightarrow>
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branch (cpair_pat p q)\<cdot>(csplit\<cdot>r)\<cdot>(x, y) = branch q\<cdot>s\<cdot>y"
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apply (simp add: branch_def cpair_pat_def)
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apply (cases "p\<cdot>x", simp_all)
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apply (cases "q\<cdot>y", simp_all)
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done
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lemmas cpair_pat [simp] =
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cpair_pat1 cpair_pat2 cpair_pat3
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lemma spair_pat [simp]:
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"branch (spair_pat p1 p2)\<cdot>r\<cdot>\<bottom> = \<bottom>"
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"\<lbrakk>x \<noteq> \<bottom>; y \<noteq> \<bottom>\<rbrakk>
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\<Longrightarrow> branch (spair_pat p1 p2)\<cdot>r\<cdot>(:x, y:) =
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branch (cpair_pat p1 p2)\<cdot>r\<cdot>(x, y)"
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by (simp_all add: branch_def spair_pat_def)
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lemma sinl_pat [simp]:
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"branch (sinl_pat p)\<cdot>r\<cdot>\<bottom> = \<bottom>"
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"x \<noteq> \<bottom> \<Longrightarrow> branch (sinl_pat p)\<cdot>r\<cdot>(sinl\<cdot>x) = branch p\<cdot>r\<cdot>x"
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"y \<noteq> \<bottom> \<Longrightarrow> branch (sinl_pat p)\<cdot>r\<cdot>(sinr\<cdot>y) = fail"
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by (simp_all add: branch_def sinl_pat_def)
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lemma sinr_pat [simp]:
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"branch (sinr_pat p)\<cdot>r\<cdot>\<bottom> = \<bottom>"
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"x \<noteq> \<bottom> \<Longrightarrow> branch (sinr_pat p)\<cdot>r\<cdot>(sinl\<cdot>x) = fail"
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"y \<noteq> \<bottom> \<Longrightarrow> branch (sinr_pat p)\<cdot>r\<cdot>(sinr\<cdot>y) = branch p\<cdot>r\<cdot>y"
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by (simp_all add: branch_def sinr_pat_def)
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lemma up_pat [simp]:
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"branch (up_pat p)\<cdot>r\<cdot>\<bottom> = \<bottom>"
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"branch (up_pat p)\<cdot>r\<cdot>(up\<cdot>x) = branch p\<cdot>r\<cdot>x"
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by (simp_all add: branch_def up_pat_def)
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lemma TT_pat [simp]:
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"branch TT_pat\<cdot>(unit_when\<cdot>r)\<cdot>\<bottom> = \<bottom>"
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"branch TT_pat\<cdot>(unit_when\<cdot>r)\<cdot>TT = succeed\<cdot>r"
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"branch TT_pat\<cdot>(unit_when\<cdot>r)\<cdot>FF = fail"
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by (simp_all add: branch_def TT_pat_def)
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lemma FF_pat [simp]:
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"branch FF_pat\<cdot>(unit_when\<cdot>r)\<cdot>\<bottom> = \<bottom>"
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"branch FF_pat\<cdot>(unit_when\<cdot>r)\<cdot>TT = fail"
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"branch FF_pat\<cdot>(unit_when\<cdot>r)\<cdot>FF = succeed\<cdot>r"
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by (simp_all add: branch_def FF_pat_def)
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lemma ONE_pat [simp]:
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"branch ONE_pat\<cdot>(unit_when\<cdot>r)\<cdot>\<bottom> = \<bottom>"
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"branch ONE_pat\<cdot>(unit_when\<cdot>r)\<cdot>ONE = succeed\<cdot>r"
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by (simp_all add: branch_def ONE_pat_def)
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subsection {* Wildcards, as-patterns, and lazy patterns *}
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definition
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wild_pat :: "'a \<rightarrow> unit match" where
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"wild_pat = (\<Lambda> x. succeed\<cdot>())"
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definition
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as_pat :: "('a \<rightarrow> 'b match) \<Rightarrow> 'a \<rightarrow> ('a \<times> 'b) match" where
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"as_pat p = (\<Lambda> x. match_case\<cdot>fail\<cdot>(\<Lambda> a. succeed\<cdot>(x, a))\<cdot>(p\<cdot>x))"
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definition
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lazy_pat :: "('a \<rightarrow> 'b::pcpo match) \<Rightarrow> ('a \<rightarrow> 'b match)" where
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"lazy_pat p = (\<Lambda> x. succeed\<cdot>(cases\<cdot>(p\<cdot>x)))"
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text {* Parse translations (patterns) *}
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translations
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"_pat _" => "CONST wild_pat"
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text {* Parse translations (variables) *}
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translations
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"_variable _ r" => "_variable _noargs r"
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text {* Print translations *}
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translations
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"_" <= "_match (CONST wild_pat) _noargs"
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lemma wild_pat [simp]: "branch wild_pat\<cdot>(unit_when\<cdot>r)\<cdot>x = succeed\<cdot>r"
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by (simp add: branch_def wild_pat_def)
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lemma as_pat [simp]:
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"branch (as_pat p)\<cdot>(csplit\<cdot>r)\<cdot>x = branch p\<cdot>(r\<cdot>x)\<cdot>x"
|
|
337 |
apply (simp add: branch_def as_pat_def)
|
|
338 |
apply (cases "p\<cdot>x", simp_all)
|
|
339 |
done
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|
340 |
|
|
341 |
lemma lazy_pat [simp]:
|
|
342 |
"branch p\<cdot>r\<cdot>x = \<bottom> \<Longrightarrow> branch (lazy_pat p)\<cdot>r\<cdot>x = succeed\<cdot>(r\<cdot>\<bottom>)"
|
|
343 |
"branch p\<cdot>r\<cdot>x = fail \<Longrightarrow> branch (lazy_pat p)\<cdot>r\<cdot>x = succeed\<cdot>(r\<cdot>\<bottom>)"
|
|
344 |
"branch p\<cdot>r\<cdot>x = succeed\<cdot>s \<Longrightarrow> branch (lazy_pat p)\<cdot>r\<cdot>x = succeed\<cdot>s"
|
|
345 |
apply (simp_all add: branch_def lazy_pat_def)
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|
346 |
apply (cases "p\<cdot>x", simp_all)+
|
|
347 |
done
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|
348 |
|
|
349 |
subsection {* Examples *}
|
|
350 |
|
|
351 |
term "Case t of (:up\<cdot>(sinl\<cdot>x), sinr\<cdot>y:) \<Rightarrow> (x, y)"
|
|
352 |
|
|
353 |
term "\<Lambda> t. Case t of up\<cdot>(sinl\<cdot>a) \<Rightarrow> a | up\<cdot>(sinr\<cdot>b) \<Rightarrow> b"
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|
354 |
|
|
355 |
term "\<Lambda> t. Case t of (:up\<cdot>(sinl\<cdot>_), sinr\<cdot>x:) \<Rightarrow> x"
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|
356 |
|
|
357 |
subsection {* ML code for generating definitions *}
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|
358 |
|
|
359 |
ML {*
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|
360 |
local open HOLCF_Library in
|
|
361 |
|
|
362 |
val beta_rules =
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|
363 |
@{thms beta_cfun cont_id cont_const cont2cont_Rep_CFun cont2cont_LAM'} @
|
|
364 |
@{thms cont2cont_fst cont2cont_snd cont2cont_Pair};
|
|
365 |
|
|
366 |
val beta_ss = HOL_basic_ss addsimps (simp_thms @ beta_rules);
|
|
367 |
|
|
368 |
fun define_consts
|
|
369 |
(specs : (binding * term * mixfix) list)
|
|
370 |
(thy : theory)
|
|
371 |
: (term list * thm list) * theory =
|
|
372 |
let
|
|
373 |
fun mk_decl (b, t, mx) = (b, fastype_of t, mx);
|
|
374 |
val decls = map mk_decl specs;
|
|
375 |
val thy = Cont_Consts.add_consts decls thy;
|
|
376 |
fun mk_const (b, T, mx) = Const (Sign.full_name thy b, T);
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|
377 |
val consts = map mk_const decls;
|
|
378 |
fun mk_def c (b, t, mx) =
|
|
379 |
(Binding.suffix_name "_def" b, Logic.mk_equals (c, t));
|
|
380 |
val defs = map2 mk_def consts specs;
|
|
381 |
val (def_thms, thy) =
|
|
382 |
PureThy.add_defs false (map Thm.no_attributes defs) thy;
|
|
383 |
in
|
|
384 |
((consts, def_thms), thy)
|
|
385 |
end;
|
|
386 |
|
|
387 |
fun prove
|
|
388 |
(thy : theory)
|
|
389 |
(defs : thm list)
|
|
390 |
(goal : term)
|
|
391 |
(tacs : {prems: thm list, context: Proof.context} -> tactic list)
|
|
392 |
: thm =
|
|
393 |
let
|
|
394 |
fun tac {prems, context} =
|
|
395 |
rewrite_goals_tac defs THEN
|
|
396 |
EVERY (tacs {prems = map (rewrite_rule defs) prems, context = context})
|
|
397 |
in
|
|
398 |
Goal.prove_global thy [] [] goal tac
|
|
399 |
end;
|
|
400 |
|
|
401 |
fun get_vars_avoiding
|
|
402 |
(taken : string list)
|
|
403 |
(args : (bool * typ) list)
|
|
404 |
: (term list * term list) =
|
|
405 |
let
|
|
406 |
val Ts = map snd args;
|
|
407 |
val ns = Name.variant_list taken (Datatype_Prop.make_tnames Ts);
|
|
408 |
val vs = map Free (ns ~~ Ts);
|
|
409 |
val nonlazy = map snd (filter_out (fst o fst) (args ~~ vs));
|
|
410 |
in
|
|
411 |
(vs, nonlazy)
|
|
412 |
end;
|
|
413 |
|
|
414 |
(******************************************************************************)
|
|
415 |
(************** definitions and theorems for pattern combinators **************)
|
|
416 |
(******************************************************************************)
|
|
417 |
|
|
418 |
fun add_pattern_combinators
|
|
419 |
(bindings : binding list)
|
|
420 |
(spec : (term * (bool * typ) list) list)
|
|
421 |
(lhsT : typ)
|
|
422 |
(exhaust : thm)
|
|
423 |
(case_const : typ -> term)
|
|
424 |
(case_rews : thm list)
|
|
425 |
(thy : theory) =
|
|
426 |
let
|
|
427 |
|
|
428 |
(* utility functions *)
|
|
429 |
fun mk_pair_pat (p1, p2) =
|
|
430 |
let
|
|
431 |
val T1 = fastype_of p1;
|
|
432 |
val T2 = fastype_of p2;
|
|
433 |
val (U1, V1) = apsnd dest_matchT (dest_cfunT T1);
|
|
434 |
val (U2, V2) = apsnd dest_matchT (dest_cfunT T2);
|
|
435 |
val pat_typ = [T1, T2] --->
|
|
436 |
(mk_prodT (U1, U2) ->> mk_matchT (mk_prodT (V1, V2)));
|
|
437 |
val pat_const = Const (@{const_name cpair_pat}, pat_typ);
|
|
438 |
in
|
|
439 |
pat_const $ p1 $ p2
|
|
440 |
end;
|
|
441 |
fun mk_tuple_pat [] = succeed_const HOLogic.unitT
|
|
442 |
| mk_tuple_pat ps = foldr1 mk_pair_pat ps;
|
|
443 |
fun branch_const (T,U,V) =
|
|
444 |
Const (@{const_name branch},
|
|
445 |
(T ->> mk_matchT U) --> (U ->> V) ->> T ->> mk_matchT V);
|
|
446 |
|
|
447 |
(* define pattern combinators *)
|
|
448 |
local
|
|
449 |
val tns = map (fst o dest_TFree) (snd (dest_Type lhsT));
|
|
450 |
|
|
451 |
fun pat_eqn (i, (bind, (con, args))) : binding * term * mixfix =
|
|
452 |
let
|
|
453 |
val pat_bind = Binding.suffix_name "_pat" bind;
|
|
454 |
val Ts = map snd args;
|
|
455 |
val Vs =
|
|
456 |
(map (K "'t") args)
|
|
457 |
|> Datatype_Prop.indexify_names
|
|
458 |
|> Name.variant_list tns
|
|
459 |
|> map (fn t => TFree (t, @{sort pcpo}));
|
|
460 |
val patNs = Datatype_Prop.indexify_names (map (K "pat") args);
|
|
461 |
val patTs = map2 (fn T => fn V => T ->> mk_matchT V) Ts Vs;
|
|
462 |
val pats = map Free (patNs ~~ patTs);
|
|
463 |
val fail = mk_fail (mk_tupleT Vs);
|
|
464 |
val (vs, nonlazy) = get_vars_avoiding patNs args;
|
|
465 |
val rhs = big_lambdas vs (mk_tuple_pat pats ` mk_tuple vs);
|
|
466 |
fun one_fun (j, (_, args')) =
|
|
467 |
let
|
|
468 |
val (vs', nonlazy) = get_vars_avoiding patNs args';
|
|
469 |
in if i = j then rhs else big_lambdas vs' fail end;
|
|
470 |
val funs = map_index one_fun spec;
|
|
471 |
val body = list_ccomb (case_const (mk_matchT (mk_tupleT Vs)), funs);
|
|
472 |
in
|
|
473 |
(pat_bind, lambdas pats body, NoSyn)
|
|
474 |
end;
|
|
475 |
in
|
|
476 |
val ((pat_consts, pat_defs), thy) =
|
|
477 |
define_consts (map_index pat_eqn (bindings ~~ spec)) thy
|
|
478 |
end;
|
|
479 |
|
|
480 |
(* syntax translations for pattern combinators *)
|
|
481 |
local
|
|
482 |
open Syntax
|
|
483 |
fun syntax c = Syntax.mark_const (fst (dest_Const c));
|
|
484 |
fun app s (l, r) = Syntax.mk_appl (Constant s) [l, r];
|
|
485 |
val capp = app @{const_syntax Rep_CFun};
|
|
486 |
val capps = Library.foldl capp
|
|
487 |
|
|
488 |
fun app_var x = Syntax.mk_appl (Constant "_variable") [x, Variable "rhs"];
|
|
489 |
fun app_pat x = Syntax.mk_appl (Constant "_pat") [x];
|
|
490 |
fun args_list [] = Constant "_noargs"
|
|
491 |
| args_list xs = foldr1 (app "_args") xs;
|
|
492 |
fun one_case_trans (pat, (con, args)) =
|
|
493 |
let
|
|
494 |
val cname = Constant (syntax con);
|
|
495 |
val pname = Constant (syntax pat);
|
|
496 |
val ns = 1 upto length args;
|
|
497 |
val xs = map (fn n => Variable ("x"^(string_of_int n))) ns;
|
|
498 |
val ps = map (fn n => Variable ("p"^(string_of_int n))) ns;
|
|
499 |
val vs = map (fn n => Variable ("v"^(string_of_int n))) ns;
|
|
500 |
in
|
|
501 |
[ParseRule (app_pat (capps (cname, xs)),
|
|
502 |
mk_appl pname (map app_pat xs)),
|
|
503 |
ParseRule (app_var (capps (cname, xs)),
|
|
504 |
app_var (args_list xs)),
|
|
505 |
PrintRule (capps (cname, ListPair.map (app "_match") (ps,vs)),
|
|
506 |
app "_match" (mk_appl pname ps, args_list vs))]
|
|
507 |
end;
|
|
508 |
val trans_rules : Syntax.ast Syntax.trrule list =
|
|
509 |
maps one_case_trans (pat_consts ~~ spec);
|
|
510 |
in
|
|
511 |
val thy = Sign.add_trrules_i trans_rules thy;
|
|
512 |
end;
|
|
513 |
|
|
514 |
(* prove strictness and reduction rules of pattern combinators *)
|
|
515 |
local
|
|
516 |
val tns = map (fst o dest_TFree) (snd (dest_Type lhsT));
|
|
517 |
val rn = Name.variant tns "'r";
|
|
518 |
val R = TFree (rn, @{sort pcpo});
|
|
519 |
fun pat_lhs (pat, args) =
|
|
520 |
let
|
|
521 |
val Ts = map snd args;
|
|
522 |
val Vs =
|
|
523 |
(map (K "'t") args)
|
|
524 |
|> Datatype_Prop.indexify_names
|
|
525 |
|> Name.variant_list (rn::tns)
|
|
526 |
|> map (fn t => TFree (t, @{sort pcpo}));
|
|
527 |
val patNs = Datatype_Prop.indexify_names (map (K "pat") args);
|
|
528 |
val patTs = map2 (fn T => fn V => T ->> mk_matchT V) Ts Vs;
|
|
529 |
val pats = map Free (patNs ~~ patTs);
|
|
530 |
val k = Free ("rhs", mk_tupleT Vs ->> R);
|
|
531 |
val branch1 = branch_const (lhsT, mk_tupleT Vs, R);
|
|
532 |
val fun1 = (branch1 $ list_comb (pat, pats)) ` k;
|
|
533 |
val branch2 = branch_const (mk_tupleT Ts, mk_tupleT Vs, R);
|
|
534 |
val fun2 = (branch2 $ mk_tuple_pat pats) ` k;
|
|
535 |
val taken = "rhs" :: patNs;
|
|
536 |
in (fun1, fun2, taken) end;
|
|
537 |
fun pat_strict (pat, (con, args)) =
|
|
538 |
let
|
|
539 |
val (fun1, fun2, taken) = pat_lhs (pat, args);
|
|
540 |
val defs = @{thm branch_def} :: pat_defs;
|
|
541 |
val goal = mk_trp (mk_strict fun1);
|
|
542 |
val rules = @{thms match_case_simps} @ case_rews;
|
|
543 |
val tacs = [simp_tac (beta_ss addsimps rules) 1];
|
|
544 |
in prove thy defs goal (K tacs) end;
|
|
545 |
fun pat_apps (i, (pat, (con, args))) =
|
|
546 |
let
|
|
547 |
val (fun1, fun2, taken) = pat_lhs (pat, args);
|
|
548 |
fun pat_app (j, (con', args')) =
|
|
549 |
let
|
|
550 |
val (vs, nonlazy) = get_vars_avoiding taken args';
|
|
551 |
val con_app = list_ccomb (con', vs);
|
|
552 |
val assms = map (mk_trp o mk_defined) nonlazy;
|
|
553 |
val rhs = if i = j then fun2 ` mk_tuple vs else mk_fail R;
|
|
554 |
val concl = mk_trp (mk_eq (fun1 ` con_app, rhs));
|
|
555 |
val goal = Logic.list_implies (assms, concl);
|
|
556 |
val defs = @{thm branch_def} :: pat_defs;
|
|
557 |
val rules = @{thms match_case_simps} @ case_rews;
|
|
558 |
val tacs = [asm_simp_tac (beta_ss addsimps rules) 1];
|
|
559 |
in prove thy defs goal (K tacs) end;
|
|
560 |
in map_index pat_app spec end;
|
|
561 |
in
|
|
562 |
val pat_stricts = map pat_strict (pat_consts ~~ spec);
|
|
563 |
val pat_apps = flat (map_index pat_apps (pat_consts ~~ spec));
|
|
564 |
end;
|
|
565 |
|
|
566 |
in
|
|
567 |
(pat_stricts @ pat_apps, thy)
|
|
568 |
end
|
|
569 |
|
|
570 |
end
|
|
571 |
*}
|
|
572 |
|
|
573 |
(*
|
|
574 |
Cut from HOLCF/Tools/domain_constructors.ML
|
|
575 |
in function add_domain_constructors:
|
|
576 |
|
|
577 |
( * define and prove theorems for pattern combinators * )
|
|
578 |
val (pat_thms : thm list, thy : theory) =
|
|
579 |
let
|
|
580 |
val bindings = map #1 spec;
|
|
581 |
fun prep_arg (lazy, sel, T) = (lazy, T);
|
|
582 |
fun prep_con c (b, args, mx) = (c, map prep_arg args);
|
|
583 |
val pat_spec = map2 prep_con con_consts spec;
|
|
584 |
in
|
|
585 |
add_pattern_combinators bindings pat_spec lhsT
|
|
586 |
exhaust case_const cases thy
|
|
587 |
end
|
|
588 |
|
|
589 |
*)
|
|
590 |
|
|
591 |
end
|