add new json subcommand

src/Subcommands/json/index.mjs

@@ -0,0 +1,38 @@
+"use strict";
+
+import fs from 'fs';
+
+import nexline from 'nexline';
+
+import a from '../../Helpers/Ansi.mjs';
+import l from '../../Helpers/Log.mjs';
+import Terrain50 from 'terrain50';
+import { write_safe, end_safe } from '../../Helpers/StreamHelpers.mjs';
+
+async function process_filename(filepath, stream_out) {
+	const stream_in = fs.createReadStream(filepath);
+	let i = 0;
+	for await(const frame of Terrain50.ParseStream(stream_in)) {
+		const obj = frame.to_json();
+		await write_safe(stream_out, JSON.stringify(obj) + "\n");
+		i++;
+	}
+	return i;
+}
+
+export default async function(settings) {
+	const stream_out = process.stdout;
+	if(settings.cli.output !== "-")
+		stream_out = fs.createWriteStream(settings.cli.output);
+	
+	if(!(settings.cli.input instanceof Array))
+		settings.cli.input = [ settings.cli.input ];
+	
+	let frames = 0;
+	for(let filepath of settings.cli.input) {
+		l.log(`Processing ${a.hicol}${filepath}${a.reset} from CLI argument`);
+		frames += await process_filename(filepath, stream_out);
+	}
+	
+	l.log(`${a.hicol}${a.fgreen}Done${a.reset}, serialised ${a.hicol}${a.fgreen}${frames}${a.reset} frames in total`);
+}

src/Subcommands/json/meta.toml

@@ -0,0 +1,13 @@
+description = "Convert 1 or more Terrain50 files to JSON (or JSONL if there are multiple frames in the input). Any logging messages are sent to stderr."
+
+[[arguments]]
+name = "input"
+description = "The input Terrain50 file(s) to operate on. May be specified multiple times. Default: stdin (can be specified explicitly with  single dash '-' (without quotes)."
+# default_value = ""
+type = "string_multi"
+
+[[arguments]]
+name = "output"
+description = "The output to write the Terrain50 instance(s) to. Defaults to stdout (represented by a single dash '-' without quotes)."
+default_value = "-"
+type = "string"