1	import Base
2	import ./json.bend as Json
3	
4	# What a CLI command answers: the exit code and the text for each stream.
5	# `out` and `err` carry their own newlines. main prints them and exits.
6	
7	type Out is Data:
8	  Out{code: U32, out: String, err: String}
9	
10	def ok(text: String) -> Out:
11	  Out{0, text ++ "\n", ""}
12	
13	def silent() -> Out:
14	  Out{0, "", ""}
15	
16	# A handled error, text mode: `Error: <message>` on stderr, exit 1.
17	def fail(msg: String) -> Out:
18	  Out{1, "", "Error: " ++ msg ++ "\n"}
19	
20	# A usage error (argparse): the message on stderr, exit 2.
21	def usage(msg: String) -> Out:
22	  Out{2, "", "cswap: error: " ++ msg ++ "\n"}
23	
24	# The --json error envelope: stdout, exit 1.
25	def json_fail(kind: String, msg: String) -> Out:
26	  Out{1, Json.emit_pretty(Json.of_pairs([
27	    ("schemaVersion", Json.JNum{"1"}),
28	    ("error", Json.of_pairs([("type", Json.JStr{kind}), ("message", Json.JStr{msg})]))])) ++ "\n", ""}
29	
30	# `json` picks the envelope or the text error.
31	def failed(json: Bool, kind: String, msg: String) -> Out:
32	  match json:
33	    case True{}:
34	      json_fail(kind, msg)
35	    case False{}:
36	      fail(msg)
37	
38	# A JSON document on stdout, indent=2.
39	def doc(j: Json.Json) -> Out:
40	  Out{0, Json.emit_pretty(j) ++ "\n", ""}