temp: commit for computer change

Author: XiaoQuark

implement-shell-tools/cat/cat-commander.mjs

@@ -0,0 +1,66 @@
+import process from "node:process";
+import { promises as fs } from "node:fs";
+import { Command } from "commander";
+
+const program = new Command();
+program
+	.name("cat")
+	.description("Concatenate files and print them to stdout")
+	.option("-n, --number", "number all output lines")
+	.option("-b, --number-nonblank", "number non-blank lines")
+	.option(
+		"-r, --replace-empty-lines",
+		"Replaces multiple consecutive empty lines with one empty line",
+	)
+	.argument("<paths...>", "Paths to process");
+
+program.parse();
+
+const options = program.opts();
+const paths = program.args;
+
+console.log(options);
+
+for (const path of paths) {
+	let contents = await fs.readFile(path, "utf8");
+	const lines = contents.split("\n");
+
+	if (options.replaceEmptyLines) {
+		contents = replaceEmptyLines(lines);
+	}
+
+	if (options.numberNonblank) {
+		contents = numberLines(lines, false);
+	} else if (options.number) {
+		contents = numberLines(lines, true);
+	}
+
+	process.stdout.write(contents);
+}
+
+function numberLines(lines, includeBlankLines) {
+	let lineNumber = 1;
+	for (let i = 0; i < lines.length; i++) {
+		if (includeBlankLines || lines[i].length > 0) {
+			lines[i] = `${lineNumber} ${lines[i]}`;
+			lineNumber++;
+		}
+	}
+
+	return lines.join("\n");
+}
+
+function replaceEmptyLines(lines) {
+	const result = [];
+	let previousLineWasBlank = false;
+
+	for (let i; i < lines.length; i++) {
+		const currentLineIsBlank = lines[i].length === 0;
+		if (!currentLineIsBlank || !previousLineWasBlank) {
+			result.push(lines[i]);
+		}
+		previousLineWasBlank = currentLineIsBlank;
+	}
+
+	return result.join("\n");
+}

implement-shell-tools/cat/cat.mjs

@@ -0,0 +1,39 @@
+import process from "node:process";
+import { promises as fs } from "node:fs";
+
+const optionDefinitions = [
+	{
+		short: "-n",
+		description: "Numbers all output lines",
+	},
+	{
+		short: "-b",
+		description: "Numbers non-blank output lines",
+	},
+];
+
+const argv = process.argv.slice(2);
+// if (argv.length != 1) {
+// 	console.error(
+// 		`Expected exactly 1 argument (a path) to be passed but got ${argv.length}.`,
+// 	);
+// 	process.exit(1);
+// }
+
+console.log(argv);
+
+const matchedOptions = optionDefinitions.find((option) => arg === option.short);
+const paths = [];
+for (const arg of argv) {
+	if (arg.match(flagRegex)) {
+		flags.push(arg);
+	} else {
+		paths.push(arg);
+	}
+}
+console.log(flags, paths);
+
+for (const path of paths) {
+	const contents = await fs.readFile(path, "utf8");
+	process.stdout.write(contents);
+}