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Consume boolean tokens #1

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Consume boolean tokens #1

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6a38ca7
Consume boolean tokens
jhladky Apr 6, 2015
c93546d
Add a signature for the JSONParser functor
jhladky Apr 6, 2015
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56 changes: 31 additions & 25 deletions sml-json.sml
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Original file line number Diff line number Diff line change
Expand Up @@ -33,7 +33,12 @@ sig
val error_handle : string * int * string -> json_data
end

functor JSONParser (Callbacks : JSON_CALLBACKS) =
functor JSONParser (Callbacks : JSON_CALLBACKS) :
sig
type json_data;
val parse : string -> json_data;
end
=
struct
type json_data = Callbacks.json_data

Expand All @@ -51,43 +56,43 @@ struct
do (inputData := String.extract (!inputData, 1, NONE))

fun peek () = String.sub (!inputData,0)
fun take () =
String.sub (!inputData,0) before
fun take () =
String.sub (!inputData,0) before
inputData := String.extract (!inputData, 1, NONE)

fun matches s = (ws(); String.isPrefix s (!inputData))
fun consume s =
if matches s then
if matches s then
(inputData := String.extract (!inputData, size s, NONE);
inputPosition := !inputPosition + size s)
else
else
raise JSONParseError ("Expected '"^s^"'", !inputPosition)

fun parseObject () =
if not (matches "{") then
if not (matches "{") then
raise JSONParseError ("Expected '{'", !inputPosition)
else
else
(consume "{"; ws ();
if matches "}" then Callbacks.json_object [] before consume "}"
else
(Callbacks.json_object (parseMembers ())
else
(Callbacks.json_object (parseMembers ())
before (ws (); consume "}")))

and parseMembers () =
parsePair () ::
parsePair () ::
(if matches "," then (consume ","; parseMembers ()) else [])

and parsePair () =
Callbacks.json_pair (parseString (),
(ws(); consume ":"; parseValue ()))

and parseArray () =
if not (matches "[") then
if not (matches "[") then
raise JSONParseError ("Expected '['", !inputPosition)
else
else
(consume "[";
if matches "]" then
Callbacks.json_array [] before consume "]"
Callbacks.json_array [] before consume "]"
else
Callbacks.json_array (parseElements ()) before (ws (); consume "]"))

Expand All @@ -99,8 +104,11 @@ struct
Callbacks.json_value (
if matches "\"" then Callbacks.json_string (parseString ()) else
if matches "-" orelse isDigit () then parseNumber () else
if matches "true" then Callbacks.json_bool true else
if matches "false" then Callbacks.json_bool false else
if matches "true" then
(consume "true"; Callbacks.json_bool true)
else if matches "false" then
(consume "false"; Callbacks.json_bool false)
else
if matches "null" then Callbacks.json_null () else
if matches "[" then parseArray () else
if matches "{" then parseObject () else
Expand All @@ -111,7 +119,7 @@ struct
consume ("\"") ;
parseChars () before consume "\"")

and parseChars () =
and parseChars () =
let
fun pickChars s =
if peek () = #"\"" (* " *) then s else
Expand All @@ -124,7 +132,7 @@ struct
let
val i = parseInt ()
in
if peek () = #"e" orelse peek () = #"E" then
if peek () = #"e" orelse peek () = #"E" then
Callbacks.json_int (valOf (Int.fromString (i^parseExp())))
else if peek () = #"." then
let
Expand All @@ -150,7 +158,7 @@ struct
f ^ parseDigits ()
end

and parseDigits () =
and parseDigits () =
let
val r = ref ""
in
Expand All @@ -165,10 +173,10 @@ struct

and parseExp () =
let
val _ =
val _ =
if peek () = #"e" orelse
peek () = #"E" then take ()
else
else
raise JSONParseError ("Invalid number", !inputPosition)

val f = if peek () = #"-" then (take (); "~")
Expand All @@ -178,10 +186,10 @@ struct
"e" ^ f ^ parseDigits ()
end

fun parse s =
fun parse s =
(inputData := s ;
inputPosition := 0 ;
parseObject ()) handle JSONParseError (m,p) =>
parseObject ()) handle JSONParseError (m,p) =>
Callbacks.error_handle (m,p,!inputData)
end

Expand All @@ -190,7 +198,7 @@ struct
type json_data = string

fun json_object l =
"{\n " ^
"{\n " ^
String.concatWith "\n " l ^
"}\n"
fun json_pair (k,v) = k ^": "^v
Expand All @@ -205,5 +213,3 @@ struct
fun error_handle (msg,pos,data) =
raise Fail ("Error: " ^ msg ^ " near " ^ Int.toString pos)
end