Further Enhancements to the Module System

.babelrc

@@ -1,3 +1,3 @@
 {
-  "presets": ["es2015", "stage-2"]
+  "presets": ["@babel/preset-env"]
 }

.eslintrc.json

@@ -9,6 +9,11 @@
     "plugin:@typescript-eslint/recommended-requiring-type-checking",
     "prettier"
   ],
+  "ignorePatterns": [
+    "**/__tests__/**",
+    "**/__mocks__/**",
+    "jest.setup.ts"
+  ],
   "parser": "@typescript-eslint/parser",
   "parserOptions": {
     "project": "tsconfig.json",

.gitignore

@@ -6,6 +6,7 @@ node_modules
 dist/
 .idea/
 coverage/
+yarn-error.log
 
 # emacs backup files
 *~

jest.setup.ts

@@ -0,0 +1,16 @@
+import { SourceMapConsumer } from "source-map"
+
+jest.mock('lodash', () => ({
+  ...jest.requireActual('lodash'),
+  memoize: jest.fn((x: any) => x),
+}))
+
+jest.mock('./src/modules/moduleLoaderAsync')
+jest.mock('./src/modules/moduleLoader')
+
+// @ts-ignore
+SourceMapConsumer.initialize({
+  'lib/mappings.wasm': 'https://unpkg.com/[email protected]/lib/mappings.wasm'
+})
+
+global.fetch = jest.fn()

package.json

@@ -33,7 +33,7 @@
   "dependencies": {
     "@babel/parser": "^7.19.4",
     "@joeychenofficial/alt-ergo-modified": "^2.4.0",
-    "@ts-morph/bootstrap": "^0.18.0",
+    "@ts-morph/bootstrap": "^0.20.0",
     "@types/estree": "0.0.52",
     "acorn": "^8.8.2",
     "acorn-class-fields": "^1.0.0",
@@ -44,7 +44,7 @@
     "js-base64": "^3.7.5",
     "lodash": "^4.17.20",
     "node-getopt": "^0.3.2",
-    "source-map": "0.7.3",
+    "source-map": "0.7.4",
     "xmlhttprequest-ts": "^1.0.1"
   },
   "scripts": {
@@ -115,6 +115,9 @@
       "/src/scm-slang",
       "/src/py-slang/"
     ],
+    "setupFilesAfterEnv": [
+      "<rootDir>/jest.setup.ts"
+    ],
     "reporters": [
       "default",
       [

src/__tests__/environment.ts

@@ -18,7 +18,10 @@ test('Function params and body identifiers are in different environment', () =>
   const context = mockContext(Chapter.SOURCE_4)
   context.prelude = null // hide the unneeded prelude
   const parsed = parse(code, context)
-  const it = evaluate(parsed as any as Program, context, false, false)
+  const it = evaluate(parsed as any as Program, context, {
+    loadTabs: false,
+    wrapModules: false
+  })
   const stepsToComment = 13 // manually counted magic number
   for (let i = 0; i < stepsToComment; i += 1) {
     it.next()

src/ec-evaluator/__tests__/__snapshots__/ec-evaluator-errors.ts.snap

@@ -792,19 +792,6 @@ Object {
 }
 `;
 
-exports[`Importing unknown variables throws UndefinedImport error: expectParsedError 1`] = `
-Object {
-  "alertResult": Array [],
-  "code": "import { foo1 } from 'one_module';",
-  "displayResult": Array [],
-  "numErrors": 1,
-  "parsedErrors": "'one_module' does not contain a definition for 'foo1'",
-  "result": undefined,
-  "resultStatus": "error",
-  "visualiseListResult": Array [],
-}
-`;
-
 exports[`In a block, every going-to-be-defined variable in the block cannot be accessed until it has been defined in the block.: expectParsedError 1`] = `
 Object {
   "alertResult": Array [],

src/ec-evaluator/__tests__/ec-evaluator-errors.ts

@@ -1,6 +1,4 @@
 /* tslint:disable:max-line-length */
-import * as _ from 'lodash'
-
 import { Chapter, Variant } from '../../types'
 import { stripIndent } from '../../utils/formatters'
 import {
@@ -10,20 +8,6 @@ import {
   expectResult
 } from '../../utils/testing'
 
-jest.spyOn(_, 'memoize').mockImplementation(func => func as any)
-
-const mockXMLHttpRequest = (xhr: Partial<XMLHttpRequest> = {}) => {
-  const xhrMock: Partial<XMLHttpRequest> = {
-    open: jest.fn(() => {}),
-    send: jest.fn(() => {}),
-    status: 200,
-    responseText: 'Hello World!',
-    ...xhr
-  }
-  jest.spyOn(window, 'XMLHttpRequest').mockImplementationOnce(() => xhrMock as XMLHttpRequest)
-  return xhrMock
-}
-
 const undefinedVariable = stripIndent`
 im_undefined;
 `
@@ -1016,35 +1000,3 @@ test('Shadowed variables may not be assigned to until declared in the current sc
     optionEC3
   ).toMatchInlineSnapshot(`"Line 3: Name variable not declared."`)
 })
-
-test('Importing unknown variables throws UndefinedImport error', () => {
-  // for getModuleFile
-  mockXMLHttpRequest({
-    responseText: `{
-    "one_module": {
-      "tabs": []
-    },
-    "another_module": {
-      "tabs": []
-    }
-  }`
-  })
-
-  // for bundle body
-  mockXMLHttpRequest({
-    responseText: `
-      require => {
-        return {
-          foo: () => 'foo',
-        }
-      }
-    `
-  })
-
-  return expectParsedError(
-    stripIndent`
-    import { foo1 } from 'one_module';
-  `,
-    optionEC
-  ).toMatchInlineSnapshot("\"'one_module' does not contain a definition for 'foo1'\"")
-})

src/ec-evaluator/interpreter.ts

@@ -6,19 +6,19 @@
  */
 
 /* tslint:disable:max-classes-per-file */
-import * as es from 'estree'
 import { uniqueId } from 'lodash'
 
 import { IOptions } from '..'
 import { UNKNOWN_LOCATION } from '../constants'
 import * as errors from '../errors/errors'
 import { RuntimeSourceError } from '../errors/runtimeSourceError'
 import Closure from '../interpreter/closure'
-import { UndefinedImportError } from '../modules/errors'
 import { loadModuleBundle, loadModuleTabs } from '../modules/moduleLoader'
+import type { ImportTransformOptions } from '../modules/moduleTypes'
 import { checkEditorBreakpoints } from '../stdlib/inspector'
 import { Context, ContiguousArrayElements, Result, Value } from '../types'
-import * as ast from '../utils/astCreator'
+import * as ast from '../utils/ast/astCreator'
+import type * as es from '../utils/ast/types'
 import { evaluateBinaryExpression, evaluateUnaryExpression } from '../utils/operators'
 import * as rttc from '../utils/rttc'
 import * as instr from './instrCreator'
@@ -99,7 +99,11 @@ export class Stash extends Stack<Value> {
  * @param context The context to evaluate the program in.
  * @returns The result of running the ECE machine.
  */
-export function evaluate(program: es.Program, context: Context, options: IOptions): Value {
+export async function evaluate(
+  program: es.Program,
+  context: Context,
+  options: IOptions
+): Promise<Value> {
   try {
     context.runtime.isRunning = true
     context.runtime.agenda = new Agenda(program)
@@ -135,8 +139,7 @@ export function resumeEvaluate(context: Context) {
 function evaluateImports(
   node: es.ImportDeclaration,
   context: Context,
-  loadTabs: boolean,
-  checkImports: boolean
+  { loadTabs, wrapModules }: ImportTransformOptions
 ) {
   try {
     const moduleName = node.source.value
@@ -153,22 +156,20 @@ function evaluateImports(
       context.moduleContexts[moduleName].tabs = loadModuleTabs(moduleName)
     }
 
-    const functions = loadModuleBundle(moduleName, context, node)
+    const functions = loadModuleBundle(moduleName, context, wrapModules, node)
     const environment = currentEnvironment(context)
     for (const spec of node.specifiers) {
-      if (spec.type !== 'ImportSpecifier') {
-        throw new Error(`Only ImportSpecifiers are supported, got: ${spec.type}`)
+      if (spec.type === 'ImportNamespaceSpecifier') {
+        throw new Error('ImportNamespaceSpecifiers are not supported!')
       }
 
-      if (checkImports && !(spec.imported.name in functions)) {
-        throw new UndefinedImportError(spec.imported.name, moduleName, node)
-      }
+      const importedName = spec.type === 'ImportDefaultSpecifier' ? 'default' : spec.imported.name
 
       declareIdentifier(context, spec.local.name, node, environment)
-      defineVariable(context, spec.local.name, functions[spec.imported.name], true, node)
+      defineVariable(context, spec.local.name, functions[importedName], true, node)
     }
   } catch (error) {
-    // console.log(error)
+    // console.error(error)
     handleRuntimeError(context, error)
   }
 }
@@ -180,16 +181,15 @@ function evaluateImports(
  * @param value The value of ec evaluating the program.
  * @returns The corresponding promise.
  */
-export function ECEResultPromise(context: Context, value: Value): Promise<Result> {
-  return new Promise((resolve, reject) => {
-    if (value instanceof ECEBreak) {
-      resolve({ status: 'suspended-ec-eval', context })
-    } else if (value instanceof ECError) {
-      resolve({ status: 'error' })
-    } else {
-      resolve({ status: 'finished', context, value })
-    }
-  })
+export async function ECEResultPromise(context: Context, promise: Promise<Value>): Promise<Result> {
+  const value = await promise
+  if (value instanceof ECEBreak) {
+    return { status: 'suspended-ec-eval', context }
+  } else if (value instanceof ECError) {
+    return { status: 'error' }
+  } else {
+    return { status: 'finished', context, value }
+  }
 }
 
 /**
@@ -475,7 +475,8 @@ const cmdEvaluators: { [type: string]: CmdEvaluator } = {
   },
 
   ImportDeclaration: function (command: es.ImportDeclaration, context: Context, agenda: Agenda) {
-    evaluateImports(command, context, true, true)
+    // TODO: Don't hardcode options
+    evaluateImports(command, context, { wrapModules: true, loadTabs: true })
   },
 
   /**

src/ec-evaluator/utils.ts

@@ -6,7 +6,7 @@ import * as errors from '../errors/errors'
 import { RuntimeSourceError } from '../errors/runtimeSourceError'
 import Closure from '../interpreter/closure'
 import { Environment, Frame, Value } from '../types'
-import * as ast from '../utils/astCreator'
+import * as ast from '../utils/ast/astCreator'
 import * as instr from './instrCreator'
 import { Agenda } from './interpreter'
 import { AgendaItem, AppInstr, AssmtInstr, Instr, InstrType } from './types'