A Collection of Isabelle Programming Hacks
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(***********************************************************************************
* Copyright (c) 2019 Achim D. Brucker
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* SPDX-License-Identifier: BSD-2-Clause
* Repository: https://git.logicalhacking.com/adbrucker/isabelle-hacks/
* Dependencies: None (assert.thy is used for testing the theory but it is
* not required for providing the functionality of this hack)
***********************************************************************************)
(***********************************************************************************
# Changelog
This comment documents all notable changes to this file in a format inspired by
[Keep a Changelog](https://keepachangelog.com/en/1.0.0/), and this project adheres
to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
## [Unreleased]
- Improved representation of IEEE reals
- Fixed serializer for definitions using equality from Pure
## [1.0.0] - 2019-01-21
- Initial release
***********************************************************************************)
chapter\<open>An Import/Export of JSON-like Formats for Isabelle/HOL\<close>
theory
"Nano_JSON"
imports
Complex_Main (* required for type real *)
keywords
"import_JSON" :: thy_decl
and "definition_JSON" :: thy_decl
and "serialize_JSON" :: thy_decl
begin
text\<open>
This theory implements an import/export format for Isabelle/HOL that is inspired by
JSON (JavaScript Object Notation). While the format defined in this theory is inspired
by the JSON standard (@{url "https://www.json.org"}), it is not fully compliant. Most
notably,
\<^item> only basic support for Unicode characters
\<^item> numbers are mapped to @{type "real"}, which is not a faithful representation of IEEE floating
point numbers, moreover, we extended the abstract syntax to allow for representing integers as
@{type "int"}.
Still, our JSON-like import/expert should work with most real-world JSON files, i.e., simplifying
the data exchange between Isabelle/HOL and tools that can read/write JSON.
Overall, this theory should enable you to work with JSON encoded data in Isabelle/HOL without
the need of implementing parsers or serialization in Isabelle/ML. You should be able to implement
mapping from the Nano JSON HOL data types to your own data types on the level of Isabelle/HOL (i.e.,
as executable HOL functions). Nevertheless, the provided ML routine that converts between the
ML representation and the HOL representation of Nano JSON can also serve as a starting point
for converting the ML representation to your own, domain-specific, HOL encoding.
\<close>
section\<open>Defining a JSON-like Data Structure\<close>
text\<open>
In this section
\<close>
datatype number = INTEGER int | REAL real
datatype json = OBJECT "(string * json) list"
| ARRAY "json list"
| NUMBER "number"
| STRING "string"
| BOOL "bool"
| NULL
text\<open>
Using the data type @{typ "json"}, we can now represent JSON encoded data easily in HOL:
\<close>
subsection\<open>Example\<close>
definition example01::json where
"example01 =
OBJECT [(''menu'', OBJECT [(''id'', STRING ''file''), (''value'', STRING ''File''),
(''popup'', OBJECT [(''menuitem'', ARRAY
[OBJECT [(''value'', STRING ''New''), (''onclick'', STRING ''CreateNewDoc()'')],
OBJECT [(''value'', STRING ''Open''), (''onclick'', STRING ''OpenDoc()'')],
OBJECT [(''value'', STRING ''Close''), (''onclick'', STRING ''CloseDoc()'')]
])]
)])]"
text\<open>
The translation of the data type @{typ "json"} to ML is straight forward. In addition, we also
provide methods for converting JSON instances between the representation as Isabelle terms and
the representation as ML data structure.
\<close>
subsection\<open>ML Implementation\<close>
ML\<open>
signature NANO_JSON_TYPE = sig
datatype number = INTEGER of int | REAL of IEEEReal.decimal_approx
datatype json = OBJECT of (string * json) list
| ARRAY of json list
| NUMBER of number
| STRING of string
| BOOL of bool
| NULL
val term_of_json: json -> term
val json_of_term: term -> json
end
structure Nano_Json_Type : NANO_JSON_TYPE = struct
datatype number = INTEGER of int | REAL of IEEEReal.decimal_approx
datatype json = OBJECT of (string * json) list
| ARRAY of json list
| NUMBER of number
| STRING of string
| BOOL of bool
| NULL
fun ieee_real_to_rat_approx rat = let
val _ = warning ("Conversion of (real) numbers is not JSON compliant.")
(* val rat = Real.toDecimal r *)
fun pow (_, 0) = 1
| pow (x, n) = if n mod 2 = 0 then pow (x*x, n div 2)
else x * pow (x*x, n div 2);
fun rat_of_dec rat = let
val sign = #sign rat
val digits = #digits rat
val exp = #exp rat
fun numerator_of _ [] = 0
| numerator_of c (x::xs) = x*pow(10,c) + (numerator_of (c+1) xs)
val numerator_abs = numerator_of 0 (rev digits)
val denominator = pow(10, (List.length digits - exp))
in
(if sign then ~ numerator_abs else numerator_abs, denominator)
end
in
case #class rat of
IEEEReal.ZERO => (0,0)
| IEEEReal.SUBNORMAL => rat_of_dec rat
| IEEEReal.NORMAL => rat_of_dec rat
| IEEEReal.INF => error "Real is INF, not yet supported."
| IEEEReal.NAN => error "Real is NaN, not yet supported."
end
fun mk_divide t1 t2 = @{const Rings.divide_class.divide (real)} $ t1 $ t2
fun mk_real_num i = HOLogic.mk_number @{typ "Real.real"} i
fun mk_real (p,q) = if q = 1 then mk_real_num p else mk_divide (mk_real_num p) (mk_real_num q)
fun dest_real (@{const Rings.divide_class.divide (real)} $a$b) =
Real.toDecimal(Real.fromInt(HOLogic.dest_number a |> snd)
/ Real.fromInt(HOLogic.dest_number b |> snd))
| dest_real t = Real.toDecimal (Real.fromInt (HOLogic.dest_number t |> snd))
fun term_of_json (OBJECT l) = @{const "OBJECT"}
$(HOLogic.mk_list ((HOLogic.mk_prodT (HOLogic.stringT,@{typ "json"})))
(map (fn (s,j) => HOLogic.mk_tuple[HOLogic.mk_string s, term_of_json j]) l))
| term_of_json (ARRAY l) = @{const "ARRAY"}
$(HOLogic.mk_list ( @{typ "json"}) (map term_of_json l))
| term_of_json (NUMBER (INTEGER i)) = @{const "NUMBER"}
$(@{const "INTEGER"}$(HOLogic.mk_number @{typ "int"} i))
| term_of_json (NUMBER (REAL r)) = @{const "NUMBER"}
$(@{const "REAL"}$(mk_real (ieee_real_to_rat_approx r)))
| term_of_json (STRING s) = @{const "STRING"}$(HOLogic.mk_string s)
| term_of_json (BOOL v) = @{const "BOOL"}$(if v then @{const "True"} else @{const "False"})
| term_of_json (NULL) = @{const "NULL"}
fun json_of_term t = let
fun dest_key_value [string, json] = (HOLogic.dest_string string, json_of json)
| dest_key_value _ = error "dest_key_value: not a key-value pair."
and json_of (@{const "OBJECT"} $ l) = OBJECT (map (dest_key_value o HOLogic.strip_tuple) (HOLogic.dest_list l))
| json_of (@{const "ARRAY"} $ l) = ARRAY (map json_of (HOLogic.dest_list l))
| json_of (@{const "NUMBER"} $ @{const "INTEGER"} $ i) = (NUMBER (INTEGER (HOLogic.dest_numeral i)))
| json_of (@{const "NUMBER"} $ @{const "REAL"} $ r) = (NUMBER (REAL (dest_real r)))
| json_of (@{const "STRING"} $ s) = STRING (HOLogic.dest_string s)
| json_of (@{const "BOOL"} $ @{const "True"}) = BOOL true
| json_of (@{const "BOOL"} $ @{const "False"}) = BOOL true
| json_of @{const "NULL"} = NULL
| json_of _ = error "Term not supported in json_of_term."
in
if type_of t = @{typ "json"} then json_of t
else error "Term not of type json."
end
end
\<close>
section\<open>Parsing Nano JSON\<close>
text\<open>
In this section, we define the infrastructure for parsing JSON-like data structures as
well as for importing them into Isabelle/HOL. This implementation was inspired by the
``Simple Standard ML JSON parser'' from Chris Cannam.
\<close>
subsection\<open>ML Implementation\<close>
subsubsection\<open>Lexer\<close>
ML\<open>
signature NANO_JSON_LEXER = sig
structure T : sig
datatype token = NUMBER of char list
| STRING of string
| BOOL of bool
| NULL
| CURLY_L
| CURLY_R
| SQUARE_L
| SQUARE_R
| COLON
| COMMA
val string_of_T : token -> string
end
val tokenize_string: string -> T.token list
end
structure Nano_Json_Lexer : NANO_JSON_LEXER = struct
structure T = struct
datatype token = NUMBER of char list
| STRING of string
| BOOL of bool
| NULL
| CURLY_L
| CURLY_R
| SQUARE_L
| SQUARE_R
| COLON
| COMMA
fun string_of_T t =
case t of NUMBER digits => String.implode digits
| STRING s => s
| BOOL b => Bool.toString b
| NULL => "null"
| CURLY_L => "{"
| CURLY_R => "}"
| SQUARE_L => "["
| SQUARE_R => "]"
| COLON => ":"
| COMMA => ","
end
fun lexer_error pos text = error (text ^ " at character position " ^
Int.toString (pos - 1))
fun token_error pos = lexer_error pos ("Unexpected token")
fun bmp_to_utf8 cp = map (Char.chr o Word.toInt)
(if cp < 0wx80
then [cp]
else if cp < 0wx800
then [Word.orb(0wxc0, Word.>>(cp,0w6)),
Word.orb(0wx8, Word.andb (cp, 0wx3f))]
else if cp < 0wx10000
then [Word.orb(0wxe0,Word.>>(cp, 0w12)),
Word.orb(0wx80, Word.andb(Word.>>(cp,0w6), 0wx3f)),
Word.orb(0wx80,Word.andb(cp, 0wx3f))]
else error ("Invalid BMP point in bmp_to_utf8 " ^ (Word.toString cp)))
fun lexNull pos acc (#"u" :: #"l" :: #"l" :: xs) =
lex (pos + 3) (T.NULL :: acc) xs
| lexNull pos _ _ = token_error pos
and lexTrue pos acc (#"r" :: #"u" :: #"e" :: xs) =
lex (pos + 3) (T.BOOL true :: acc) xs
| lexTrue pos _ _ = token_error pos
and lexFalse pos acc (#"a" :: #"l" :: #"s" :: #"e" :: xs) =
lex (pos + 4) (T.BOOL false :: acc) xs
| lexFalse pos _ _ = token_error pos
and lexChar tok pos acc xs =
lex pos (tok :: acc) xs
and lexString pos acc cc =
let datatype escaped = ESCAPED | NORMAL
fun lexString' pos _ ESCAPED [] =
lexer_error pos "End of input during escape sequence"
| lexString' pos _ NORMAL [] =
lexer_error pos "End of input during string"
| lexString' pos text ESCAPED (x :: xs) =
let fun esc c = lexString' (pos + 1) (c :: text) NORMAL xs
in case x of
#"\"" => esc x
| #"\\" => esc x
| #"/" => esc x
| #"b" => esc #"\b"
| #"f" => esc #"\f"
| #"n" => esc #"\n"
| #"r" => esc #"\r"
| #"t" => esc #"\t"
| _ => lexer_error pos ("Invalid escape \\" ^
Char.toString x)
end
| lexString' pos text NORMAL (#"\\" :: #"u" ::a::b::c::d:: xs) =
if List.all Char.isHexDigit [a,b,c,d]
then case Word.fromString ("0wx" ^ (String.implode [a,b,c,d])) of
SOME w => (let val utf = rev (bmp_to_utf8 w) in
lexString' (pos + 6) (utf @ text)
NORMAL xs
end
handle Fail err => lexer_error pos err)
| NONE => lexer_error pos "Invalid Unicode BMP escape sequence"
else lexer_error pos "Invalid Unicode BMP escape sequence"
| lexString' pos text NORMAL (x :: xs) =
if Char.ord x < 0x20
then lexer_error pos "Invalid unescaped control character"
else
case x of
#"\"" => (rev text, xs, pos + 1)
| #"\\" => lexString' (pos + 1) text ESCAPED xs
| _ => lexString' (pos + 1) (x :: text) NORMAL xs
val (text, rest, newpos) = lexString' pos [] NORMAL cc
in
lex newpos (T.STRING (String.implode text) :: acc) rest
end
and lexNumber firstChar pos acc cc =
let val valid = String.explode ".+-e"
fun lexNumber' pos digits [] = (rev digits, [], pos)
| lexNumber' pos digits (x :: xs) =
if x = #"E" then lexNumber' (pos + 1) (#"e" :: digits) xs
else if Char.isDigit x orelse List.exists (fn c => x = c) valid
then lexNumber' (pos + 1) (x :: digits) xs
else (rev digits, x :: xs, pos)
val (digits, rest, newpos) =
lexNumber' (pos - 1) [] (firstChar :: cc)
in
case digits of
[] => token_error pos
| _ => lex newpos (T.NUMBER digits :: acc) rest
end
and lex _ acc [] = rev acc
| lex pos acc (x::xs) =
(case x of
#" " => lex
| #"\t" => lex
| #"\n" => lex
| #"\r" => lex
| #"{" => lexChar T.CURLY_L
| #"}" => lexChar T.CURLY_R
| #"[" => lexChar T.SQUARE_L
| #"]" => lexChar T.SQUARE_R
| #":" => lexChar T.COLON
| #"," => lexChar T.COMMA
| #"\"" => lexString
| #"t" => lexTrue
| #"f" => lexFalse
| #"n" => lexNull
| x => lexNumber x) (pos + 1) acc xs
fun tokenize_string str = lex 1 [] (String.explode str)
end
\<close>
subsubsection\<open>Parser\<close>
ML\<open>
signature NANO_JSON_PARSER = sig
val json_of_string : string -> Nano_Json_Type.json
val term_of_json_string : string -> term
end
structure Nano_Json_Parser : NANO_JSON_PARSER = struct
open Nano_Json_Type
open Nano_Json_Lexer
fun show [] = "end of input"
| show (tok :: _) = T.string_of_T tok
val parse_error = error
fun parseNumber digits =
let open Char
fun okExpDigits [] = false
| okExpDigits (c :: []) = isDigit c
| okExpDigits (c :: cs) = isDigit c andalso okExpDigits cs
fun okExponent [] = false
| okExponent (#"+" :: cs) = okExpDigits cs
| okExponent (#"-" :: cs) = okExpDigits cs
| okExponent cc = okExpDigits cc
fun okFracTrailing [] = true
| okFracTrailing (c :: cs) =
(isDigit c andalso okFracTrailing cs) orelse
(c = #"e" andalso okExponent cs)
fun okFraction [] = false
| okFraction (c :: cs) =
isDigit c andalso okFracTrailing cs
fun okPosTrailing [] = true
| okPosTrailing (#"." :: cs) = okFraction cs
| okPosTrailing (#"e" :: cs) = okExponent cs
| okPosTrailing (c :: cs) =
isDigit c andalso okPosTrailing cs
fun okPositive [] = false
| okPositive (#"0" :: []) = true
| okPositive (#"0" :: #"." :: cs) = okFraction cs
| okPositive (#"0" :: #"e" :: cs) = okExponent cs
| okPositive (#"0" :: _) = false
| okPositive (c :: cs) = isDigit c andalso okPosTrailing cs
fun okNumber (#"-" :: cs) = okPositive cs
| okNumber cc = okPositive cc
in
if okNumber digits then let
val number = String.implode digits
in
if List.all (Char.isDigit) (String.explode number)
then (case Int.fromString (String.implode digits) of
NONE => parse_error "Number out of range"
| SOME r => INTEGER r)
else (case IEEEReal.fromString (String.implode digits) of
NONE => parse_error "Number out of range"
| SOME r => REAL r)
end
else parse_error ("Invalid number \"" ^ (String.implode digits) ^ "\"")
end
fun parseObject (T.CURLY_R :: xs) = (OBJECT [], xs)
| parseObject tokens =
let fun parsePair (T.STRING key :: T.COLON :: xs) = let
val (j, xs) = parseTokens xs
in
((key, j), xs)
end
| parsePair other =
parse_error("Object key/value pair expected around \"" ^
show other ^ "\"")
fun parseObject' _ [] = parse_error "End of input during object"
| parseObject' acc tokens =
case parsePair tokens of
(pair, T.COMMA :: xs) =>
parseObject' (pair :: acc) xs
| (pair, T.CURLY_R :: xs) =>
(OBJECT (rev (pair :: acc)), xs)
| (_, _) =>parse_error "Expected , or } after object element"
in
parseObject' [] tokens
end
and parseArray (T.SQUARE_R :: xs) = (ARRAY [], xs)
| parseArray tokens =
let fun parseArray' _ [] = error "End of input during array"
| parseArray' acc tokens =
case parseTokens tokens of
(j, T.COMMA :: xs) => parseArray' (j :: acc) xs
| (j, T.SQUARE_R :: xs) => (ARRAY (rev (j :: acc)), xs)
| (_, _) => error "Expected , or ] after array element"
in
parseArray' [] tokens
end
and parseTokens [] = parse_error "Value expected"
| parseTokens (tok :: xs) =
(case tok of
T.NUMBER d => (NUMBER ((parseNumber d)), xs)
| T.STRING s => (STRING s, xs)
| T.BOOL b => (BOOL b, xs)
| T.NULL => (NULL, xs)
| T.CURLY_L => parseObject xs
| T.SQUARE_L => parseArray xs
| _ => parse_error ("Unexpected token " ^ T.string_of_T tok ^
" before " ^ show xs))
fun json_of_string str = case parseTokens (Nano_Json_Lexer.tokenize_string str) of
(value, []) => value
| (_, _) => parse_error "Extra data after input"
val term_of_json_string = term_of_json o json_of_string
end
\<close>
subsection\<open>Isar Setup\<close>
subsubsection\<open>The JSON Cartouche\<close>
syntax "_cartouche_nano_json" :: "cartouche_position \<Rightarrow> 'a" ("JSON _")
parse_translation\<open>
let
fun translation args =
let
fun err () = raise TERM ("Common._cartouche_nano_json", args)
fun input s pos = Symbol_Pos.implode (Symbol_Pos.cartouche_content (Symbol_Pos.explode (s, pos)))
in
case args of
[(c as Const (@{syntax_const "_constrain"}, _)) $ Free (s, _) $ p] =>
(case Term_Position.decode_position p of
SOME (pos, _) => c $ Nano_Json_Parser.term_of_json_string (input s pos) $ p
| NONE => err ())
| _ => err ()
end
in
[(@{syntax_const "_cartouche_nano_json"}, K translation)]
end
\<close>
subsubsection\<open>Isar Top-Level Commands\<close>
ML\<open>
structure Nano_Json_Parser_Isar = struct
fun make_const_def (constname, trm) lthy = let
val arg = ((Binding.name constname, NoSyn), ((Binding.name (constname^"_def"),[]), trm))
val ((_, (_ , thm)), lthy') = Local_Theory.define arg lthy
in
(thm, lthy')
end
fun def_json name json = snd o (make_const_def (name, Nano_Json_Parser.term_of_json_string json ))
fun def_json_file name filename lthy = let
val filename = Path.explode filename
val thy = Proof_Context.theory_of lthy
val master_dir = Resources.master_directory thy
val abs_filename = if (Path.is_absolute filename)
then filename
else Path.append master_dir filename
val json = File.read abs_filename
in
def_json name json lthy
end
val jsonFileP = Parse.name -- Parse.name
val jsonP = Parse.name -- Parse.cartouche
end
\<close>
ML\<open>
val _ = Outer_Syntax.local_theory @{command_keyword "definition_JSON"} "Define JSON."
(Nano_Json_Parser_Isar.jsonP >> (fn (name, json) => Nano_Json_Parser_Isar.def_json name json));
val _ = Outer_Syntax.local_theory @{command_keyword "import_JSON"} "Define JSON from file."
(Nano_Json_Parser_Isar.jsonFileP >> (fn (name, filename) => Nano_Json_Parser_Isar.def_json_file name filename));
\<close>
subsection\<open>Examples\<close>
text\<open>
Now we can use the JSON Cartouche for defining JSON-like data ``on-the-fly'', e.g.:
\<close>
lemma \<open>y == JSON\<open>{"name": [true,false,"test"]}\<close>\<close>
oops
text\<open>
Note that you need to escape quotes within the JSON Cartouche, if you are using
quotes as lemma delimiters, e.g.,:
\<close>
lemma "y == JSON\<open>{\"name\": [true,false,\"test\"]}\<close>"
oops
text\<open>
Thus, we recommend to use the Cartouche delimiters when using the JSON Cartouche with non
trivial data structures:
\<close>
lemma \<open> example01 == JSON \<open>{"menu": {
"id": "file",
"value": "File",
"popup": {
"menuitem": [
{"value": "New", "onclick": "CreateNewDoc()"},
{"value": "Open", "onclick": "OpenDoc()"},
{"value": "Close", "onclick": "CloseDoc()"}
]
}
}}\<close>\<close>
by(simp add: example01_def)
text\<open>
Using the top level Isar commands defined in the last section, we can now easily define
JSON-like data:
\<close>
definition_JSON example02 \<open>
{"menu": {
"id": "file",
"value": "File",
"popup": {
"menuitem": [
{"value": "New", "onclick": "CreateNewDoc()"},
{"value": "Open", "onclick": "OpenDoc()"},
{"value": "Close", "onclick": "CloseDoc()"}
]
}
}}
\<close>
thm example02_def
lemma "example01 = example02"
by(simp add: example01_def example02_def)
text\<open>
Moreover, we can import JSON from external files:
\<close>
import_JSON example03 "example.json"
thm example03_def
lemma "example01 = example03"
by(simp add: example01_def example03_def)
section\<open>Serializing Nano JSON\<close>
text\<open>
In this section, we define the necessary infrastructure to serialize (export) data from HOL using
a JSON-like data structure that other JSON tools should be able to import.
\<close>
subsection\<open>ML Implementation\<close>
ML\<open>
signature NANO_JSON_SERIALIZER = sig
val serialize_json: Nano_Json_Type.json -> string
val serialize_json_pretty: Nano_Json_Type.json -> string
val serialize_term: term -> string
val serialize_term_pretty: term -> string
end
structure Nano_Json_Serializer : NANO_JSON_SERIALIZER = struct
open Nano_Json_Type
fun escapeJsonString s =
let fun bs c = "\\"^(Char.toString c)
fun escape #"\"" = bs #"\""
| escape #"\\" = bs #"\\"
| escape #"\b" = bs #"b"
| escape #"\f" = bs #"f"
| escape #"\n" = bs #"n"
| escape #"\r" = bs #"r"
| escape #"\t" = bs #"t"
| escape c =
let val ord = Char.ord c
in
if ord < 0x20
then let val hex = Word.toString (Word.fromInt ord)
val prfx = if ord < 0x10 then "\\u000" else "\\u00"
in
prfx^hex
end
else
Char.toString c
end
in
String.concat (map escape (String.explode s))
end
fun serialize pretty json = let
val nl = if pretty = NONE then "" else "\n"
fun indent' 0 = ""
| indent' n = " "^(indent' (n-1))
fun indent n = (case pretty of NONE => ""
| SOME n' => indent' (n+n'))
fun serialize' _ (OBJECT []) = "{}"
| serialize' _ (ARRAY []) = "[]"
| serialize' n (OBJECT pp) = "{"^nl^(indent (n+1)) ^ String.concatWith
(","^nl^(indent (n+1)))
(map (fn (key, value) =>
serialize' (n+1) (STRING key) ^ ":" ^
serialize' (n+1) value) pp) ^
nl^(indent n)^"}"
| serialize' n (ARRAY arr) = "["^nl^(indent (n+1)) ^ String.concatWith
(","^nl^(indent (n+1)))
(map (serialize' (n+1) ) arr) ^
nl^(indent n)^"]"
| serialize' _ (NUMBER (REAL n)) = String.implode (map (fn #"~" => #"-" | c => c)
(String.explode (IEEEReal.toString n)))
| serialize' _ (NUMBER (INTEGER n)) = String.implode (map (fn #"~" => #"-" | c => c)
(String.explode (Int.toString n)))
| serialize' _ (STRING s) = "\"" ^ escapeJsonString s ^ "\""
| serialize' _ (BOOL b) = Bool.toString b
| serialize' _ NULL = "null"
in
(serialize' 0 json)^nl
end
val serialize_json = serialize NONE
val serialize_json_pretty = serialize (SOME 0)
val serialize_term = (serialize NONE) o json_of_term
val serialize_term_pretty = (serialize (SOME 0)) o json_of_term
end
\<close>
subsection\<open>Isar Setup\<close>
ML\<open>
structure Nano_Json_Serialize_Isar = struct
fun export_json ctxt json_const filename =
let
val thy = Proof_Context.theory_of ctxt
val master_dir = Resources.master_directory thy
val term = Thm.concl_of (Global_Theory.get_thm thy (json_const^"_def"))
val json_term = case term of
Const (@{const_name "Pure.eq"}, _) $ _ $ json_term => json_term
| _ $ (_ $ json_term) => json_term
| _ => error ("Term structure not supported: "
^(Sledgehammer_Util.hackish_string_of_term ctxt term))
val json_string = Nano_Json_Serializer.serialize_term_pretty json_term
in
case filename of
SOME filename => let
val filename = Path.explode filename
val abs_filename = if (Path.is_absolute filename)
then filename
else Path.append master_dir filename
in
File.write (abs_filename) json_string
handle (IO.Io{name=name,...}) => warning ("Could not write \""^name^"\".")
end
| NONE => tracing json_string
end
end
\<close>
ML\<open>
Outer_Syntax.command ("serialize_JSON", Position.none) "export JSON data to an external file"
(Parse.name -- Scan.option Parse.name >> (fn (const_name,filename) =>
(Toplevel.keep (fn state => Nano_Json_Serialize_Isar.export_json (Toplevel.context_of state) const_name filename))));
\<close>
subsection\<open>Examples\<close>
text\<open>
We can now serialize JSON and print the result in the output window of Isabelle/HOL:
\<close>
serialize_JSON example01
text\<open>
Alternatively, we can export the serialized JSON into a file:
\<close>
serialize_JSON example01 example01.json
section\<open>Putting Everything Together\<close>
text\<open>
For convenience, we provide an ML structure that provides access to both the parser and the
serializer:,
\<close>
ML\<open>
structure Nano_Json = struct
open Nano_Json_Type
open Nano_Json_Parser
open Nano_Json_Serializer
end
\<close>
end