1	import Base
2	import bend-kit-json@0.3.0.0/json.bend as Json
3	
4	# Sole owner of JSON operations. Consumers import THIS module for all
5	# encode/parse/get work; they import the kit package ONLY for the Val type in
6	# annotations (Bend cannot alias types across modules — same convention as
7	# MyLsmStore.Sess).
8	# TRUST BOUNDARY: Json.parse is structural recursion. Json.encode is @unsafe
9	# upstream (work-list walk, documented in kit source); canonical-bytes
10	# (equal content => identical text) is covered by json_bytes_probe and the
11	# differential check vs Python json, not by proof. If kit ships a safe
12	# encoder, only this file changes.
13	
14	# Wraps text as a JSON string value.
15	def make_str(+text: String) -> Json.Val:
16	  Json.Str{text}
17	
18	# Wraps a value list as a JSON array.
19	def make_arr(items: List<&2, Json.Val>) -> Json.Val:
20	  Json.Arr{items}
21	
22	# Builds one object field pair.
23	def make_kv(+field_key: String, field_value: Json.Val) -> Sigma<&2, &2, String, _ => Json.Val>:
24	  (field_key, field_value)
25	
26	# Inserts one field pair into the map.
27	def fold_pair(field_map: Map<&2, Json.Val>, field_pair: Sigma<&2, &2, String, _ => Json.Val>) -> Map<&2, Json.Val>:
28	  match field_pair:
29	    case (field_key, field_value):
30	      Map.set(&2, Json.Val, field_map, field_key, field_value)
31	
32	# Folds a field list into a map; the list shrinks first.
33	def fold_fields(remaining_fields: List<&2, Sigma<&2, &2, String, _ => Json.Val>>, field_map: Map<&2, Json.Val>) -> Map<&2, Json.Val>:
34	  match remaining_fields:
35	    case Nil{}:
36	      field_map
37	    case Con{field_pair, tail_fields}:
38	      fold_fields(tail_fields, fold_pair(field_map, field_pair))
39	
40	# Builds an object; keys come out sorted by construction.
41	def make_obj(fields: List<&2, Sigma<&2, &2, String, _ => Json.Val>>) -> Json.Val:
42	  Json.Obj{fold_fields(fields, Map.new(&2, Json.Val))}
43	
44	# Parses stored text; None on malformed input.
45	def parse_text(+stored_text: String) -> Maybe<&2, Json.Val>:
46	  Json.parse(stored_text)
47	
48	# Looks up an object field; None when absent or not an object.
49	def get_field(+document: Json.Val, +field_name: String) -> Maybe<&2, Json.Val>:
50	  Json.get(document, field_name)
51	
52	# Unwraps a string value; None otherwise.
53	def as_str(json_value: Json.Val) -> Maybe<&2, String>:
54	  match json_value:
55	    case Json.Str{text}:
56	      Some{text}
57	    case _:
58	      None{}
59	
60	# Unwraps an array value; None otherwise.
61	def as_arr(json_value: Json.Val) -> Maybe<&2, List<&2, Json.Val>>:
62	  match json_value:
63	    case Json.Arr{items}:
64	      Some{items}
65	    case _:
66	      None{}
67	
68	# Encodes with keys sorted; the canonical bytes.
69	def encode_canonical(+document: Json.Val) -> String:
70	  Json.encode(document)