Rename directory "engines" to "languages"

languages/worker-errors.ts

@@ -0,0 +1,83 @@
+import { DocumentRange } from "./types";
+
+/**
+ * Special error class, to be thrown when encountering a
+ * syntax error while parsing a program.
+ */
+export class ParseError extends Error {
+  /** Location of syntax error in the program */
+  range: DocumentRange;
+
+  /**
+   * Create an instance of ParseError
+   * @param message Error message
+   * @param range Location of syntactically incorrect code
+   */
+  constructor(message: string, range: DocumentRange) {
+    super(message);
+    this.name = "ParseError";
+    this.range = range;
+  }
+}
+
+/**
+ * Special error class, to be thrown when encountering an error
+ * at runtime that is indicative of a bug in the user's program.
+ */
+export class RuntimeError extends Error {
+  /**
+   * Create an instance of RuntimeError
+   * @param message Error message
+   */
+  constructor(message: string) {
+    super(message);
+    this.name = "RuntimeError";
+  }
+}
+
+/** Check if an error object is instance of a ParseError */
+export const isParseError = (error: any): error is ParseError => {
+  return error instanceof ParseError || error.name === "ParseError";
+};
+
+/** Check if an error object is instance of a RuntimeError */
+export const isRuntimeError = (error: any): error is RuntimeError => {
+  return error instanceof RuntimeError || error.name === "RuntimeError";
+};
+
+/** Error sent by worker in case of parsing error */
+export type WorkerParseError = {
+  name: "ParseError";
+  message: string;
+  range: DocumentRange;
+};
+
+/** Error sent by worker in case error at runtime */
+export type WorkerRuntimeError = {
+  name: "RuntimeError";
+  message: string;
+};
+
+/** Error sent by worker indicating an implementation bug */
+export type WorkerError = {
+  name: string;
+  message: string;
+  stack?: string;
+};
+
+/** Serialize a RuntimeError instance into a plain object */
+export const serializeRuntimeError = (
+  error: RuntimeError
+): WorkerRuntimeError => {
+  return { name: "RuntimeError", message: error.message };
+};
+
+/** Serialize a ParseError instance into a plain object */
+export const serializeParseError = (error: ParseError): WorkerParseError => {
+  return { name: "ParseError", message: error.message, range: error.range };
+};
+
+/** Serialize an arbitrary error into a plain object */
+export const serializeError = (error: Error): WorkerError => {
+  return { name: error.name, message: error.message, stack: error.stack };
+};