process.js

README.md

@@ -14,4 +14,5 @@ first.
 - `simple.css` css styling for minimal sites
 - `chat.js` chat server; connect with netcat. somewhat buggy
 - `request.js` async wrapper for http
+- `process.js` sed-like batch text editor
 

process.js

@@ -0,0 +1,99 @@
+if(!process.argv[2]) throw "no file";
+const fs = require("fs");
+const readline = require("readline");
+const rl = readline.createInterface({
+	input: process.stdin,
+	output: process.stdout,
+	prompt: "=> ",
+});
+
+const commands = {
+	p(data) { throw data },
+	c(data) { throw data.length },
+	r(data, args) {
+		if(arr("s", data, args)) return data;
+		if(args.length < 2) throw "too few args";
+		return data.replace(new RegExp(args[0], args[2] || ""), args[1]);
+	},
+	m(data, args) {
+		if(arr("m", data, args)) return data;
+		if(args.length < 1) throw "too few args";
+		return data.match(new RegExp(args[0], args[1] || "")) || [];
+	},
+	d(data, args) {
+		if(arr("d", data, args)) return data;
+		if(args.length < 1) throw "too few args";
+		return data.replace(new RegExp(args[0], "g"), "");
+	},
+	t(data, args) {
+		if(arr("t", data, args)) return data;
+		switch(args[0] || "all") {
+			case "all": return data.trim();
+			case "start": return data.trimStart();
+			case "end": return data.trimEnd();
+			default: throw "unknown trim";
+		}
+	},
+	f(data, args) {
+		if(!(data instanceof Array)) throw "cant";
+		if(args.length < 1) throw "too few args";
+		const reg = new RegExp(args[0], args[1] || "");
+		return data.filter(i => reg.test(i));
+	},
+	w(data, args) {
+		if(data instanceof Array) throw "cant";
+		fs.writeFileSync(process.argv[2], data);
+		throw `wrote ${data.length} bytes`;
+	},
+	s(data, args) {
+		if(data instanceof Array) throw "cant";
+		return data.split(args);
+	},
+	j(data, args) {
+		if(!(data instanceof Array)) throw "cant";
+		return data.join(args);
+	},
+};
+
+function special(char) {
+	switch(char) {
+		case "n": return "\n";
+		case "r": return "\r";
+		case "t": return "\t";
+		default: return char;
+	}
+}
+
+function split(line) {
+	const parts = [""];
+	for(let i = 0; i < line.length; i++) {
+		switch(line[i]) {
+			case "\\": parts[parts.length - 1] += special(line[++i]); break;
+			case "/": parts.push(""); break;
+			default: parts[parts.length - 1] += line[i]; break;
+		}
+	}
+	return parts.filter(i => i);
+}
+
+function arr(func, data, args) {
+	if(data instanceof Array) {
+		for(let i = 0; i < data.length; i++) data[i] = commands[func](data[i], args);
+		return true;
+	}
+}
+
+let data = fs.readFileSync(process.argv[2], "utf8");
+console.log(`read ${data.length} bytes`);
+rl.prompt();
+rl.on("line", (line) => {
+	const parts = split(line);
+	if(!commands.hasOwnProperty(parts[0])) {
+		return console.log("command does not exist"), rl.prompt();
+	}
+	try {
+		data = commands[parts[0]](data, parts.slice(1));
+		if(data instanceof Array) data = data.flat();
+	} catch (err) { console.log(err) }
+	rl.prompt();
+});