1	import Base
2	import ../json.bend as Json
3	import ./yamlw.bend as W
4	import ./yamlr.bend as R
5	
6	# YAML for the JSON data model: `emit` writes block style (yamlw.bend),
7	# `parse` reads the subset cswap writes plus plain block maps, lists and
8	# scalars (yamlr.bend).
9	
10	def emit(j: Json.Json) -> String:
11	  W.emit(j)
12	
13	def flowy(+s: String) -> Bool:
14	  String.starts_with(String.trim_start(s), "{") || String.starts_with(String.trim_start(s), "[")
15	
16	# JSON is YAML: a document that opens with `{` or `[` is read as JSON when it
17	# is JSON (nested flow collections, quoted keys), else by the block reader.
18	def parse.json(r: Result<&2, &2, String, Json.Json>, +s: String) -> Result<&2, &2, String, Json.Json>:
19	  match r:
20	    case Done{j}:
21	      Done{j}
22	    case Fail{e}:
23	      R.parse(s)
24	
25	def parse.pick(flow: Bool, +s: String) -> Result<&2, &2, String, Json.Json>:
26	  match flow:
27	    case True{}:
28	      parse.json(Json.parse(s), s)
29	    case False{}:
30	      R.parse(s)
31	
32	def parse(+s: String) -> Result<&2, &2, String, Json.Json>:
33	  parse.pick(flowy(s), s)