Merge 4134102 into 1f0df33

src/builtins/index.ts

@@ -7,6 +7,7 @@ import { builtinCommandExit } from "./exit";
 import { builtinCommandNot } from "./not";
 import { builtinCommandPrintf } from "./printf";
 import { builtinCommandPwd } from "./pwd";
+import { builtinCommandReturn } from "./return";
 import { builtinCommandSource } from "./source";
 import { BuiltinCommandCallback } from "./types";
 import { builtinCommandUnset } from "./unset";
@@ -26,6 +27,7 @@ export const builtinCommandMapping: Record<string, BuiltinCommandCallback> = {
   false: builtinCommand(0, 0, () => Promise.resolve(ExitStatus.ERROR)),
   pwd: builtinCommandPwd,
   printf: builtinCommandPrintf,
+  return: builtinCommandReturn,
   source: builtinCommandSource,
   true: builtinCommand(0, 0, () => Promise.resolve(ExitStatus.OK)),
   unset: builtinCommandUnset,

src/builtins/return.ts

@@ -0,0 +1,18 @@
+import { ReturnError } from "../error";
+import { ExitStatus } from "../status";
+import { builtinCommand } from "./utils";
+
+/**
+ * Exits from an function call with optional status code.
+ */
+export const builtinCommandReturn = builtinCommand(0, 1, (context, n) => {
+  const nn = n != null ? parseInt(n) : ExitStatus.OK;
+
+  if (isNaN(nn)) {
+    context.stderr.write(`Illegal number: ${n}\n`);
+
+    return Promise.resolve(ExitStatus.ERROR);
+  }
+
+  return Promise.reject(new ReturnError(nn));
+});

src/context.ts

@@ -9,7 +9,7 @@ import { PassThrough } from "stream";
 
 import { Statement } from "./ast";
 import { BuiltinCommandCallback, builtinCommandMapping } from "./builtins";
-import { JuokseError } from "./error";
+import { JuokseError, ReturnError } from "./error";
 import { ExitStatus } from "./status";
 import { executeScript } from "./execute";
 
@@ -231,16 +231,22 @@ export class Context extends EventEmitter {
         this.variables[`${i + 1}`] = args[i];
       }
 
-      return executeScript(this, [resolvedExecutable]).then(() => {
-        this.variables["?"] = `${ExitStatus.OK}`;
-        this.emit("process finish", {
-          executable,
-          args,
-          status: ExitStatus.OK,
-        });
-
-        return { status: ExitStatus.OK };
-      });
+      return executeScript(this, [resolvedExecutable])
+        .then(() => {
+          this.variables["?"] = `${ExitStatus.OK}`;
+          this.emit("process finish", {
+            executable,
+            args,
+            status: ExitStatus.OK,
+          });
+
+          return { status: ExitStatus.OK };
+        })
+        .catch((err) =>
+          err instanceof ReturnError
+            ? Promise.resolve<ExecutionResult>({ status: err.status })
+            : Promise.reject(err)
+        );
     }
 
     return new Promise<ExecutionResult>((resolve, reject) => {

src/error.ts

@@ -45,3 +45,13 @@ export class ContinueError extends JuokseError {
     Object.setPrototypeOf(this, ContinueError.prototype);
   }
 }
+
+export class ReturnError extends JuokseError {
+  public readonly status: number;
+
+  public constructor(status: number) {
+    super("Used 'return' outside function call.");
+    this.status = status;
+    Object.setPrototypeOf(this, ReturnError.prototype);
+  }
+}