core: Updated ShellInterpreter

Author: Prozilla

packages/core/src/features/shell/commands/doubleBracket.ts

@@ -0,0 +1,106 @@
+import { EXIT_CODE } from "../../../constants";
+import { VirtualFolder } from "../../virtual-drive";
+import { Command } from "../command";
+import { Shell } from "../shell";
+
+const toExitCode = (result: boolean) => result ? EXIT_CODE.success : EXIT_CODE.generalError;
+
+const UNARY_OPERATORS: Record<string, (value: string, workingDirectory: VirtualFolder) => boolean> = {
+	"-z": (value) => value.length === 0,
+	"-n": (value) => value.length > 0,
+	"-f": (value, workingDirectory) => workingDirectory.navigate(value)?.isFile() ?? false,
+	"-d": (value, workingDirectory) => workingDirectory.navigate(value)?.isFolder() ?? false,
+	"-e": (value, workingDirectory) => workingDirectory.navigate(value) != null,
+};
+
+const BINARY_OPERATORS: Record<string, (left: string, right: string) => boolean> = {
+	"=":   (left, right) => left === right,
+	"==":  (left, right) => left === right,
+	"!=":  (left, right) => left !== right,
+	"-eq": (left, right) => Number(left) === Number(right),
+	"-ne": (left, right) => Number(left) !== Number(right),
+	"-lt": (left, right) => Number(left) <   Number(right),
+	"-le": (left, right) => Number(left) <=  Number(right),
+	"-gt": (left, right) => Number(left) >   Number(right),
+	"-ge": (left, right) => Number(left) >=  Number(right),
+};
+
+class ConditionalParser {
+	tokens: string[];
+	index = 0;
+	workingDirectory: VirtualFolder;
+
+	constructor(tokens: string[], workingDirectory: VirtualFolder) {
+		this.tokens = tokens;
+		this.workingDirectory = workingDirectory;
+	}
+
+	parse(): boolean {
+		return this.parseOr();
+	}
+
+	parseOr(): boolean {
+		let result = this.parseAnd();
+		while (this.tokens[this.index] === "||") {
+			this.index++;
+			result = this.parseAnd() || result;
+		}
+		return result;
+	}
+
+	parseAnd(): boolean {
+		let result = this.parsePrimary();
+		while (this.tokens[this.index] === "&&") {
+			this.index++;
+			result = this.parsePrimary() && result;
+		}
+		return result;
+	}
+
+	parsePrimary(): boolean {
+		const token = this.tokens[this.index++];
+
+		if (token === "!") return !this.parsePrimary();
+
+		if (token === "(") {
+			const result = this.parseOr();
+			this.index++; // Skip ")"
+			return result;
+		}
+
+		if (token in UNARY_OPERATORS) {
+			const value = this.tokens[this.index++];
+			return UNARY_OPERATORS[token](value, this.workingDirectory);
+		}
+
+		const nextToken = this.tokens[this.index];
+		if (nextToken in BINARY_OPERATORS) {
+			this.index++;
+			const right = this.tokens[this.index++];
+			return BINARY_OPERATORS[nextToken](token, right);
+		}
+
+		return token.length > 0;
+	}
+}
+
+export const doubleBracket = new Command()
+	.setName("[[")
+	.setRequireArgs(true)
+	.setManual({
+		purpose: "Evaluate a conditional expression",
+		usage: "[[ expression ]]",
+	})
+	.setExecute(function(this: Command, args, { stderr, workingDirectory }) {
+		if (args.at(-1) !== "]]")
+			return Shell.writeError(stderr, this.name, "missing `]]'");
+
+		const tokens = args.slice(0, -1);
+		if (tokens.length === 0) return EXIT_CODE.generalError;
+
+		try {
+			return toExitCode(new ConditionalParser(tokens, workingDirectory).parse());
+		} catch {
+			return EXIT_CODE.misuseOfBuiltins;
+		}
+	});

packages/core/src/features/shell/commands/printenv.ts

@@ -13,12 +13,12 @@ export const printenv = new Command()
 			args.forEach((arg) => {
 				const value = exportedVars[arg];
 				// eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
-				if (value !== undefined) stdout.write(`${value}\n`);
+				if (value !== undefined) stdout.write(`${value}`);
 			});
 			return;
 		}
 
 		Object.entries(exportedVars).forEach(([key, value]) => {
-			stdout.write(`${key}=${value}\n`);
+			stdout.write(`${key}=${value}`);
 		});
 	});