1(*  Title:      HOL/Code_Evaluation.thy
2    Author:     Florian Haftmann, TU Muenchen
3*)
4
5section \<open>Term evaluation using the generic code generator\<close>
6
7theory Code_Evaluation
8imports Typerep Limited_Sequence
9keywords "value" :: diag
10begin
11
12subsection \<open>Term representation\<close>
13
14subsubsection \<open>Terms and class \<open>term_of\<close>\<close>
15
16datatype (plugins only: extraction) "term" = dummy_term
17
18definition Const :: "String.literal \<Rightarrow> typerep \<Rightarrow> term" where
19  "Const _ _ = dummy_term"
20
21definition App :: "term \<Rightarrow> term \<Rightarrow> term" where
22  "App _ _ = dummy_term"
23
24definition Abs :: "String.literal \<Rightarrow> typerep \<Rightarrow> term \<Rightarrow> term" where
25  "Abs _ _ _ = dummy_term"
26
27definition Free :: "String.literal \<Rightarrow> typerep \<Rightarrow> term" where
28  "Free _ _ = dummy_term"
29
30code_datatype Const App Abs Free
31
32class term_of = typerep +
33  fixes term_of :: "'a \<Rightarrow> term"
34
35lemma term_of_anything: "term_of x \<equiv> t"
36  by (rule eq_reflection) (cases "term_of x", cases t, simp)
37
38definition valapp :: "('a \<Rightarrow> 'b) \<times> (unit \<Rightarrow> term)
39  \<Rightarrow> 'a \<times> (unit \<Rightarrow> term) \<Rightarrow> 'b \<times> (unit \<Rightarrow> term)" where
40  "valapp f x = (fst f (fst x), \<lambda>u. App (snd f ()) (snd x ()))"
41
42lemma valapp_code [code, code_unfold]:
43  "valapp (f, tf) (x, tx) = (f x, \<lambda>u. App (tf ()) (tx ()))"
44  by (simp only: valapp_def fst_conv snd_conv)
45
46
47subsubsection \<open>Syntax\<close>
48
49definition termify :: "'a \<Rightarrow> term" where
50  [code del]: "termify x = dummy_term"
51
52abbreviation valtermify :: "'a \<Rightarrow> 'a \<times> (unit \<Rightarrow> term)" where
53  "valtermify x \<equiv> (x, \<lambda>u. termify x)"
54
55locale term_syntax
56begin
57
58notation App (infixl "<\<cdot>>" 70)
59  and valapp (infixl "{\<cdot>}" 70)
60
61end
62
63interpretation term_syntax .
64
65no_notation App (infixl "<\<cdot>>" 70)
66  and valapp (infixl "{\<cdot>}" 70)
67
68
69subsection \<open>Tools setup and evaluation\<close>
70
71context
72begin
73
74qualified definition TERM_OF :: "'a::term_of itself"
75where
76  "TERM_OF = snd (Code_Evaluation.term_of :: 'a \<Rightarrow> _, TYPE('a))"
77
78qualified definition TERM_OF_EQUAL :: "'a::term_of itself"
79where
80  "TERM_OF_EQUAL = snd (\<lambda>(a::'a). (Code_Evaluation.term_of a, HOL.eq a), TYPE('a))"
81
82end
83
84lemma eq_eq_TrueD:
85  fixes x y :: "'a::{}"
86  assumes "(x \<equiv> y) \<equiv> Trueprop True"
87  shows "x \<equiv> y"
88  using assms by simp
89
90code_printing
91  type_constructor "term" \<rightharpoonup> (Eval) "Term.term"
92| constant Const \<rightharpoonup> (Eval) "Term.Const/ ((_), (_))"
93| constant App \<rightharpoonup> (Eval) "Term.$/ ((_), (_))"
94| constant Abs \<rightharpoonup> (Eval) "Term.Abs/ ((_), (_), (_))"
95| constant Free \<rightharpoonup> (Eval) "Term.Free/ ((_), (_))"
96
97ML_file "Tools/code_evaluation.ML"
98
99code_reserved Eval Code_Evaluation
100
101ML_file "~~/src/HOL/Tools/value_command.ML"
102
103
104subsection \<open>Dedicated \<open>term_of\<close> instances\<close>
105
106instantiation "fun" :: (typerep, typerep) term_of
107begin
108
109definition
110  "term_of (f :: 'a \<Rightarrow> 'b) =
111    Const (STR ''Pure.dummy_pattern'')
112      (Typerep.Typerep (STR ''fun'') [Typerep.typerep TYPE('a), Typerep.typerep TYPE('b)])"
113
114instance ..
115
116end
117
118declare [[code drop: rec_term case_term
119  "term_of :: typerep \<Rightarrow> _" "term_of :: term \<Rightarrow> _" "term_of :: String.literal \<Rightarrow> _"
120  "term_of :: _ Predicate.pred \<Rightarrow> term" "term_of :: _ Predicate.seq \<Rightarrow> term"]]
121
122code_printing
123  constant "term_of :: integer \<Rightarrow> term" \<rightharpoonup> (Eval) "HOLogic.mk'_number/ HOLogic.code'_integerT"
124| constant "term_of :: String.literal \<Rightarrow> term" \<rightharpoonup> (Eval) "HOLogic.mk'_literal"
125
126declare [[code drop: "term_of :: integer \<Rightarrow> _"]]
127
128lemma term_of_integer [unfolded typerep_fun_def typerep_num_def typerep_integer_def, code]:
129  "term_of (i :: integer) =
130  (if i > 0 then 
131     App (Const (STR ''Num.numeral_class.numeral'') (TYPEREP(num \<Rightarrow> integer)))
132      (term_of (num_of_integer i))
133   else if i = 0 then Const (STR ''Groups.zero_class.zero'') TYPEREP(integer)
134   else
135     App (Const (STR ''Groups.uminus_class.uminus'') TYPEREP(integer \<Rightarrow> integer))
136       (term_of (- i)))"
137  by (rule term_of_anything [THEN meta_eq_to_obj_eq])
138
139code_reserved Eval HOLogic
140
141
142subsection \<open>Generic reification\<close>
143
144ML_file "~~/src/HOL/Tools/reification.ML"
145
146
147subsection \<open>Diagnostic\<close>
148
149definition tracing :: "String.literal \<Rightarrow> 'a \<Rightarrow> 'a" where
150  [code del]: "tracing s x = x"
151
152code_printing
153  constant "tracing :: String.literal => 'a => 'a" \<rightharpoonup> (Eval) "Code'_Evaluation.tracing"
154
155
156hide_const dummy_term valapp
157hide_const (open) Const App Abs Free termify valtermify term_of tracing
158
159end
160