{"body":"Adds a direct translation of Rust's Result type, for later use in BuildHIR and \npossibly other passes","commit":{"shortRevision":"73f09248fb","authorEmail":"poteto@users.noreply.github.com","revision":"73f09248fb9f6642f89580e3de7cfcb37b605186","authorName":"Lauren Tan","subject":"Add Result","authoredAt":"2023-01-12T19:35:20-05:00"},"files":[{"status":"A","path":"compiler\/forget\/src\/__tests__\/Result-test.ts"},{"status":"A","path":"compiler\/forget\/src\/lib\/Result.ts"}],"parents":["325987d744ed992a7147dba78a89d8ea80e0e85d"],"patch":"diff --git a\/compiler\/forget\/src\/__tests__\/Result-test.ts b\/compiler\/forget\/src\/__tests__\/Result-test.ts\nnew file mode 100644\nindex 0000000000..5d6fa40d8b\n--- \/dev\/null\n+++ b\/compiler\/forget\/src\/__tests__\/Result-test.ts\n@@ -0,0 +1,130 @@\n+import { Err, Ok, Result } from \"..\/lib\/Result\";\n+\n+function addMax10(a: number, b: number): Result {\n+ const n = a + b;\n+ return n > 10 ? Err(`${n} is too high`) : Ok(n);\n+}\n+\n+function onlyFoo(foo: string): Result {\n+ return foo === \"foo\" ? Ok(foo) : Err(foo);\n+}\n+\n+describe(\"Result\", () => {\n+ test(\".map\", () => {\n+ expect(addMax10(1, 1).map((n) => n * 2)).toEqual(Ok(4));\n+ expect(addMax10(10, 10).map((n) => n * 2)).toEqual(Err(\"20 is too high\"));\n+ });\n+\n+ test(\".mapErr\", () => {\n+ expect(addMax10(1, 1).mapErr((e) => `not a number: ${e}`)).toEqual(Ok(2));\n+ expect(addMax10(10, 10).mapErr((e) => `couldn't add: ${e}`)).toEqual(\n+ Err(\"couldn't add: 20 is too high\")\n+ );\n+ });\n+\n+ test(\".mapOr\", () => {\n+ expect(onlyFoo(\"foo\").mapOr(42, (v) => v.length)).toEqual(3);\n+ expect(onlyFoo(\"bar\").mapOr(42, (v) => v.length)).toEqual(42);\n+ });\n+\n+ test(\".mapOrElse\", () => {\n+ expect(\n+ onlyFoo(\"foo\").mapOrElse(\n+ () => 42,\n+ (v) => v.length\n+ )\n+ ).toEqual(3);\n+ expect(\n+ onlyFoo(\"bar\").mapOrElse(\n+ () => 42,\n+ (v) => v.length\n+ )\n+ ).toEqual(42);\n+ });\n+\n+ test(\".andThen\", () => {\n+ expect(addMax10(1, 1).andThen((n) => Ok(n * 2))).toEqual(Ok(4));\n+ expect(addMax10(10, 10).andThen((n) => Ok(n * 2))).toEqual(\n+ Err(\"20 is too high\")\n+ );\n+ });\n+\n+ test(\".and\", () => {\n+ expect(addMax10(1, 1).and(Ok(4))).toEqual(Ok(4));\n+ expect(addMax10(10, 10).and(Ok(4))).toEqual(Err(\"20 is too high\"));\n+ expect(addMax10(1, 1).and(Err(\"hehe\"))).toEqual(Err(\"hehe\"));\n+ expect(addMax10(10, 10).and(Err(\"hehe\"))).toEqual(Err(\"20 is too high\"));\n+ });\n+\n+ test(\".or\", () => {\n+ expect(addMax10(1, 1).or(Ok(4))).toEqual(Ok(2));\n+ expect(addMax10(10, 10).or(Ok(4))).toEqual(Ok(4));\n+ expect(addMax10(1, 1).or(Err(\"hehe\"))).toEqual(Ok(2));\n+ expect(addMax10(10, 10).or(Err(\"hehe\"))).toEqual(Err(\"hehe\"));\n+ });\n+\n+ test(\".orElse\", () => {\n+ expect(addMax10(1, 1).orElse((str) => Err(str.toUpperCase()))).toEqual(\n+ Ok(2)\n+ );\n+ expect(addMax10(10, 10).orElse((str) => Err(str.toUpperCase()))).toEqual(\n+ Err(\"20 IS TOO HIGH\")\n+ );\n+ });\n+\n+ test(\".isOk\", () => {\n+ expect(addMax10(1, 1).isOk()).toBeTruthy();\n+ expect(addMax10(10, 10).isOk()).toBeFalsy();\n+ });\n+\n+ test(\".isErr\", () => {\n+ expect(addMax10(1, 1).isErr()).toBeFalsy();\n+ expect(addMax10(10, 10).isErr()).toBeTruthy();\n+ });\n+\n+ test(\".expect\", () => {\n+ expect(addMax10(1, 1).expect(\"a number under 10\")).toEqual(2);\n+ expect(() => {\n+ addMax10(10, 10).expect(\"a number under 10\");\n+ }).toThrowErrorMatchingInlineSnapshot(\n+ `\"a number under 10: 20 is too high\"`\n+ );\n+ });\n+\n+ test(\".expectErr\", () => {\n+ expect(() => {\n+ addMax10(1, 1).expectErr(\"a number under 10\");\n+ }).toThrowErrorMatchingInlineSnapshot(`\"a number under 10: 2\"`);\n+ expect(addMax10(10, 10).expectErr(\"a number under 10\")).toEqual(\n+ \"20 is too high\"\n+ );\n+ });\n+\n+ test(\".unwrap\", () => {\n+ expect(addMax10(1, 1).unwrap()).toEqual(2);\n+ expect(() => {\n+ addMax10(10, 10).unwrap();\n+ }).toThrowErrorMatchingInlineSnapshot(\n+ `\"Can't unwrap \\`Err\\` to \\`Ok\\`: 20 is too high\"`\n+ );\n+ });\n+\n+ test(\".unwrapOr\", () => {\n+ expect(addMax10(1, 1).unwrapOr(4)).toEqual(2);\n+ expect(addMax10(10, 10).unwrapOr(4)).toEqual(4);\n+ });\n+\n+ test(\".unwrapOrElse\", () => {\n+ expect(addMax10(1, 1).unwrapOrElse(() => 4)).toEqual(2);\n+ expect(addMax10(10, 10).unwrapOrElse((s) => s.length)).toEqual(14);\n+ });\n+\n+ test(\".unwrapErr\", () => {\n+ expect(() => {\n+ addMax10(1, 1).unwrapErr();\n+ }).toThrowErrorMatchingInlineSnapshot(\n+ `\"Can't unwrap \\`Ok\\` to \\`Err\\`: 2\"`\n+ );\n+ expect(addMax10(10, 10).unwrapErr()).toEqual(\"20 is too high\");\n+ });\n+});\ndiff --git a\/compiler\/forget\/src\/lib\/Result.ts b\/compiler\/forget\/src\/lib\/Result.ts\nnew file mode 100644\nindex 0000000000..e2130f14d0\n--- \/dev\/null\n+++ b\/compiler\/forget\/src\/lib\/Result.ts\n@@ -0,0 +1,244 @@\n+\/**\n+ * Copyright (c) Facebook, Inc. and its affiliates.\n+ *\n+ * This source code is licensed under the MIT license found in the\n+ * LICENSE file in the root directory of this source tree.\n+ *\/\n+\n+\/\/ Direct translation of Rust's Result type, although some ownership related methods are omitted.\n+export interface Result {\n+ \/**\n+ * Maps a `Result` to `Result` by applying a function to a contained `Ok` value,\n+ * leaving an `Err` value untouched.\n+ *\n+ * This function can be used to compose the results of two functions.\n+ *\/\n+ map(fn: (val: T) => U): Result;\n+ \/**\n+ * Maps a `Result` to `Result` by applying a function to a contained `Err` value,\n+ * leaving an `Ok` value untouched.\n+ *\n+ * This function can be used to pass through a successful result while handling an error.\n+ *\/\n+ mapErr(fn: (val: E) => F): Result;\n+ \/**\n+ * Returns the provided default (if `Err`), or applies a function to the contained value\n+ * (if `Ok`).\n+ *\n+ * Arguments passed to {@link mapOr} are eagerly evaluated; if you are passing the result of a\n+ * function call, it is recommended to use {@link mapOrElse}, which is lazily evaluated.\n+ *\/\n+ mapOr(fallback: U, fn: (val: T) => U): U;\n+ \/**\n+ * Maps a `Result` to `U` by applying fallback function default to a contained `Err` value,\n+ * or function `fn` to a contained `Ok` value.\n+ *\n+ * This function can be used to unpack a successful result while handling an error.\n+ *\/\n+ mapOrElse(fallback: () => U, fn: (val: T) => U): U;\n+ \/**\n+ * Calls `fn` if the result is `Ok`, otherwise returns the `Err` value of self.\n+ *\n+ * This function can be used for control flow based on Result values.\n+ *\/\n+ andThen(fn: (val: T) => Result): Result;\n+ \/**\n+ * Returns res if the result is `Ok`, otherwise returns the `Err` value of self.\n+ *\n+ * Arguments passed to {@link and} are eagerly evaluated; if you are passing the result of a\n+ * function call, it is recommended to use {@link andThen}, which is lazily evaluated.\n+ *\/\n+ and(res: Result): Result;\n+ \/**\n+ * Returns `res` if the result is `Err`, otherwise returns the `Ok` value of self.\n+ *\n+ * Arguments passed to {@link or} are eagerly evaluated; if you are passing the result of a\n+ * function call, it is recommended to use {@link orElse}, which is lazily evaluated.\n+ *\/\n+ or(res: Result): Result;\n+ \/**\n+ * Calls `fn` if the result is `Err`, otherwise returns the `Ok` value of self.\n+ *\n+ * This function can be used for control flow based on result values.\n+ *\/\n+ orElse(fn: (val: E) => Result): Result;\n+ \/**\n+ * Returns `true` if the result is `Ok`.\n+ *\/\n+ isOk(): this is OkImpl;\n+ \/**\n+ * Returns `true` if the result is `Err`.\n+ *\/\n+ isErr(): this is ErrImpl;\n+ \/**\n+ * Returns the contained `Ok` value or throws.\n+ *\/\n+ expect(msg: string): T;\n+ \/**\n+ * Returns the contained `Err` value or throws.\n+ *\/\n+ expectErr(msg: string): E;\n+ \/**\n+ * Returns the contained `Ok` value.\n+ *\/\n+ unwrap(): T;\n+ \/**\n+ * Returns the contained `Ok` value or a provided default.\n+ *\n+ * Arguments passed to {@link unwrapOr} are eagerly evaluated; if you are passing the result of a\n+ * function call, it is recommended to use {@link unwrapOrElse}, which is lazily evaluated.\n+ *\/\n+ unwrapOr(fallback: T): T;\n+ \/**\n+ * Returns the contained `Ok` value or computes it from a closure.\n+ *\/\n+ unwrapOrElse(fallback: (val: E) => T): T;\n+ \/**\n+ * Returns the contained `Err` value or throws.\n+ *\/\n+ unwrapErr(): E;\n+}\n+\n+export function Ok(val: T): OkImpl {\n+ return new OkImpl(val);\n+}\n+\n+class OkImpl implements Result {\n+ constructor(private val: T) {}\n+\n+ map(fn: (val: T) => U): Result {\n+ return new OkImpl(fn(this.val));\n+ }\n+\n+ mapErr(_fn: (val: never) => F): Result {\n+ return this;\n+ }\n+\n+ mapOr(_fallback: U, fn: (val: T) => U): U {\n+ return fn(this.val);\n+ }\n+\n+ mapOrElse(_fallback: () => U, fn: (val: T) => U): U {\n+ return fn(this.val);\n+ }\n+\n+ andThen(fn: (val: T) => Result): Result {\n+ return fn(this.val);\n+ }\n+\n+ and(res: Result): Result {\n+ return res;\n+ }\n+\n+ or(_res: Result): Result {\n+ return this;\n+ }\n+\n+ orElse(_fn: (val: never) => Result): Result {\n+ return this;\n+ }\n+\n+ isOk(): boolean {\n+ return true;\n+ }\n+\n+ isErr(): boolean {\n+ return false;\n+ }\n+\n+ expect(_msg: string): T {\n+ return this.val;\n+ }\n+\n+ expectErr(msg: string): never {\n+ throw new Error(`${msg}: ${this.val}`);\n+ }\n+\n+ unwrap(): T {\n+ return this.val;\n+ }\n+\n+ unwrapOr(_fallback: T): T {\n+ return this.val;\n+ }\n+\n+ unwrapOrElse(_fallback: (val: never) => T): T {\n+ return this.val;\n+ }\n+\n+ unwrapErr(): never {\n+ throw new Error(`Can't unwrap \\`Ok\\` to \\`Err\\`: ${this.val}`);\n+ }\n+}\n+\n+export function Err(val: E): ErrImpl {\n+ return new ErrImpl(val);\n+}\n+\n+class ErrImpl implements Result {\n+ constructor(private val: E) {}\n+\n+ map(_fn: (val: never) => U): Result {\n+ return this;\n+ }\n+\n+ mapErr(fn: (val: E) => F): Result {\n+ return new ErrImpl(fn(this.val));\n+ }\n+\n+ mapOr(fallback: U, _fn: (val: never) => U): U {\n+ return fallback;\n+ }\n+\n+ mapOrElse(fallback: () => U, _fn: (val: never) => U): U {\n+ return fallback();\n+ }\n+\n+ andThen(_fn: (val: never) => Result): Result {\n+ return this;\n+ }\n+\n+ and(_res: Result): Result {\n+ return this;\n+ }\n+\n+ or(res: Result): Result {\n+ return res;\n+ }\n+\n+ orElse(fn: (val: E) => ErrImpl): Result {\n+ return fn(this.val);\n+ }\n+\n+ isOk(): boolean {\n+ return false;\n+ }\n+\n+ isErr(): boolean {\n+ return true;\n+ }\n+\n+ expect(msg: string): never {\n+ throw new Error(`${msg}: ${this.val}`);\n+ }\n+\n+ expectErr(_msg: string): E {\n+ return this.val;\n+ }\n+\n+ unwrap(): never {\n+ throw new Error(`Can't unwrap \\`Err\\` to \\`Ok\\`: ${this.val}`);\n+ }\n+\n+ unwrapOr(fallback: T): T {\n+ return fallback;\n+ }\n+\n+ unwrapOrElse(fallback: (val: E) => T): T {\n+ return fallback(this.val);\n+ }\n+\n+ unwrapErr(): E {\n+ return this.val;\n+ }\n+}\n"}

dillon1000/react

Files changed