3 (* A generic lens for Json files *)
4 (* Based on the following grammar from http://www.json.org/ *)
5 (* Object ::= '{'Members ? '}' *)
6 (* Members ::= Pair+ *)
7 (* Pair ::= String ':' Value *)
8 (* Array ::= '[' Elements ']' *)
9 (* Elements ::= Value ( "," Value )* *)
10 (* Value ::= String | Number | Object | Array | "true" | "false" | "null" *)
11 (* String ::= "\"" Char* "\"" *)
12 (* Number ::= /-?[0-9]+(\.[0-9]+)?([eE][+-]?[0-9]+)?/ *)
17 let eol = del spc "\n"
18 let delim (c:string) (d:string) = del (c . spc) d
19 let dels (s:string) = del s s
21 let comma = delim "," ","
22 let colon = delim ":" ":"
23 let lbrace = delim "{" "{"
24 let rbrace = delim "}" "}"
25 let lbrack = delim "[" "["
26 let rbrack = delim "]" "]"
29 let q = del "\"" "\"" in
30 q . store /[^"]*/ . q . ws (* " Emacs, relax *)
32 let number = [ label "number" . store /-?[0-9]+(\.[0-9]+)?([eE][+-]?[0-9]+)?/ . ws ]
33 let str = [ label "string" . str_store ]
35 let const (r:regexp) = [ label "const" . store r . ws ]
37 let value0 = str | number | const /true|false|null/
39 let fix_value (value:lens) =
40 let array = [ label "array" . lbrack . (Build.opt_list value comma)? . rbrack ] in
41 let pair = [ label "entry" . str_store . colon . value ] in
42 let obj = [ label "dict" . lbrace . (Build.opt_list pair comma)? . rbrace ] in
43 (str | number | obj | array | const /true|false|null/)
45 (* Typecheck finitely deep nesting *)
46 let value1 = fix_value value0
47 let value2 = fix_value value1
49 (* Process arbitrarily deeply nested JSON objects *)
50 let rec rlns = fix_value rlns