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feat(module-source): parser pipeline support
This exposes a new function, `createModuleSourcePasses()` for use with `@endo/parser-pipeline`. Refactored code for reuse between `createModuleSourcePasses()` and `ModuleSource()`
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Lines changed: 531 additions & 99 deletions

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‎.changeset/ripe-showers-remain.md‎

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---
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'@endo/module-source': minor
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---
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Expose `createModuleSourcePasses()` for use with `@endo/parser-pipeline`.

‎packages/module-source/index.js‎

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export * from './src/external.types.js';
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export { ModuleSource } from './src/module-source.js';
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export { createModuleSourcePasses } from './src/visitor-passes.js';

‎packages/module-source/src/babel-plugin.js‎

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import * as h from './hidden.js';
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/**
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* @import {PluginFactory, TransformSourceParams} from './types/module-source.js'
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*/
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/*
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* Collects all of the identifiers on the left-hand-side of an exported
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* assignment expression, deeply exploring complex destructuring assignment.
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}
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};
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/**
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* Creates a plugin for the Babel parser that analyzes and transforms module source code.
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*
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* @param {TransformSourceParams} options
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* @returns {{analyzePlugin: PluginFactory, transformPlugin: PluginFactory}}
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*/
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function makeModulePlugins(options) {
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const {
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sourceType,
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} else {
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// Rewrite to be just name = value.
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soften(id);
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options.hoistedDecls.push([name]);
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options.hoistedDecls.push([name, false, undefined]);
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replacements.push(
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t.expressionStatement(
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t.assignmentExpression(

‎packages/module-source/src/functor.js‎

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/**
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* Shared logic for building the SES functor source string and assembling
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* the frozen module record (see {@link ModuleSourceRecord}).
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*
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* @module
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*/
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import * as h from './hidden.js';
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/**
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* @import {ModuleSourceRecord} from './types/module-source.js'
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*/
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const { keys, values, freeze: objectFreeze } = Object;
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/**
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* It's {@link objectFreeze | Object.freeze} without the `Readonly`!
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*
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* @privateRemarks Remove this if we decide to make the fields of `PrecompiledModuleSource` readonly.
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*/
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const freeze = /** @type {<T>(v: T) => T} */ (objectFreeze);
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const { stringify: js } = JSON;
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/**
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* Builds the SES functor source string from generated code and the analysis
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* state accumulated during the analyzer and transform passes.
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*
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* Constructs the `$h_imports([...])` preamble from `sourceOptions.importSources`,
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* `importDecls`, and `hoistedDecls`, then wraps `scriptSource` in the SES
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* functor calling convention.
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*
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* @param {string} scriptSource The code produced by `@babel/generator`
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* after all transform passes.
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* @param {Record<string, any>} sourceOptions The mutable state bag populated
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* by `makeModulePlugins`.
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* @param {string} [sourceUrl] The source URL for the module.
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* @returns {string} The functor source string.
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*/
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export const buildFunctorSource = (scriptSource, sourceOptions, sourceUrl) => {
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const isrc = sourceOptions.importSources;
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let preamble = sourceOptions.importDecls.join(',');
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if (preamble !== '') {
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preamble = `let ${preamble};`;
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}
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preamble += `${h.HIDDEN_IMPORTS}([${keys(isrc)
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.map(
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src =>
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`[${js(src)}, [${Object.entries(isrc[src])
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.map(([exp, upds]) => `[${js(exp)},[${upds.join(',')}]]`)
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.join(',')}]]`,
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)
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.join(',')}]);`;
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preamble += sourceOptions.hoistedDecls
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.map(([vname, isOnce, cvname]) => {
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let src = '';
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if (cvname) {
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src = `Object.defineProperty(${cvname},'name',{value:${js(vname)}});`;
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}
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const hDeclId = isOnce ? h.HIDDEN_ONCE : h.HIDDEN_LIVE;
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src += `${hDeclId}.${vname}(${cvname || ''});`;
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return src;
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})
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.join('');
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let functorSource = `\
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({imports:${h.HIDDEN_IMPORTS},liveVar:${h.HIDDEN_LIVE},onceVar:${h.HIDDEN_ONCE},import:${h.HIDDEN_IMPORT},importMeta:${h.HIDDEN_META}})=>(function(){'use strict';\
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${preamble}\
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${scriptSource}
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})()
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`;
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if (sourceUrl) {
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functorSource += `//# sourceURL=${sourceUrl}\n`;
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}
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return functorSource;
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};
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/**
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* Computes the derived arrays (`imports`, `exports`, `reexports`) from the
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* raw maps in `sourceOptions` and assembles a {@link ModuleSourceRecord}.
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*
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* @param {Record<string, any>} sourceOptions The mutable state bag populated
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* by `makeModulePlugins`.
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* @param {string} functorSource The functor source string from
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* {@link buildFunctorSource}.
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* @returns {ModuleSourceRecord}
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*/
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export const buildModuleRecord = (sourceOptions, functorSource) => {
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for (const entry of values(sourceOptions.liveExportMap)) {
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freeze(entry);
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}
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for (const entry of values(sourceOptions.fixedExportMap)) {
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freeze(entry);
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}
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for (const reexports of values(sourceOptions.reexportMap)) {
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for (const pair of reexports) {
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freeze(pair);
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}
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freeze(reexports);
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}
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return freeze({
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imports: freeze([...keys(sourceOptions.imports)]),
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exports: freeze(
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[
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...keys(sourceOptions.liveExportMap),
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...keys(sourceOptions.fixedExportMap),
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...values(sourceOptions.reexportMap)
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.flat()
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.map(([_, exportName]) => exportName),
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].sort(),
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),
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reexports: freeze([...sourceOptions.exportAlls].sort()),
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__syncModuleProgram__: functorSource,
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__liveExportMap__: freeze(sourceOptions.liveExportMap),
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__fixedExportMap__: freeze(sourceOptions.fixedExportMap),
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__reexportMap__: freeze(sourceOptions.reexportMap),
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__needsImport__: sourceOptions.dynamicImport.present,
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__needsImportMeta__: sourceOptions.importMeta.present,
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});
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};

‎packages/module-source/src/transform-analyze.js‎

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import makeModulePlugins from './babel-plugin.js';
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import * as h from './hidden.js';
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import { createSourceOptions } from './source-options.js';
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import { buildFunctorSource, buildModuleRecord } from './functor.js';
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const { freeze } = Object;
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/** @import {Options} from './module-source.js' */
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/** @import {ModuleSourceOptions} from './types/module-source.js' */
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const makeCreateStaticRecord = transformSource =>
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/**
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*
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* @param {string} moduleSource
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* @param {Options} options
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* @param {ModuleSourceOptions} options
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*/
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function createStaticRecord(
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moduleSource,
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{ sourceUrl, sourceMapUrl, sourceMap, sourceMapHook } = {},
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) {
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// Transform the Module source code.
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const sourceOptions = {
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const sourceOptions = createSourceOptions({
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sourceUrl,
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sourceMap,
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sourceMapUrl,
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sourceMapHook,
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sourceType: 'module',
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// exportNames of variables that are only initialized and used, but
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// never assigned to.
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fixedExportMap: Object.create(null),
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// Record of imported module specifier names to list of importNames.
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// The importName '*' is that module's module namespace object.
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imports: Object.create(null),
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// List of module specifiers that we export all from.
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exportAlls: [],
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// exportNames of variables that are assigned to, or reexported and
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// therefore assumed live. A reexported variable might not have any
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// localName.
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reexportMap: Object.create(null),
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liveExportMap: Object.create(null),
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hoistedDecls: [],
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importSources: Object.create(null),
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importDecls: [],
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dynamicImport: { present: false },
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// enables passing import.meta usage hints up.
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importMeta: { present: false },
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};
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});
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if (moduleSource.startsWith('#!')) {
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// Comment out the shebang lines.
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moduleSource = `//${moduleSource}`;
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);
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}
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let preamble = sourceOptions.importDecls.join(',');
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if (preamble !== '') {
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preamble = `let ${preamble};`;
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}
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const js = JSON.stringify;
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const isrc = sourceOptions.importSources;
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preamble += `${h.HIDDEN_IMPORTS}([${Object.keys(isrc)
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.map(
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src =>
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`[${js(src)}, [${Object.entries(isrc[src])
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.map(([exp, upds]) => `[${js(exp)},[${upds.join(',')}]]`)
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.join(',')}]]`,
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)
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.join(',')}]);`;
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preamble += sourceOptions.hoistedDecls
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.map(([vname, isOnce, cvname]) => {
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let src = '';
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if (cvname) {
83-
// It's a function assigned to, so set its name property.
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src = `Object.defineProperty(${cvname},'name',{value:${js(vname)}});`;
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}
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const hDeclId = isOnce ? h.HIDDEN_ONCE : h.HIDDEN_LIVE;
87-
src += `${hDeclId}.${vname}(${cvname || ''});`;
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return src;
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})
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.join('');
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// The outer function destructures the module calling convention's internal
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// variables into hidden lexical variables.
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// The inner function binds `this` to `undefined` and overshadows the
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// evaluator's `arguments` with a completely empty `arguments` object.
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// There is no avoiding the overshadowing of `globalThis.arguments` if it
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// exists in this emulation of ESM since the evaluator binds `arguments` as
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// well.
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// Relies on the evaluator to ensure these functions are strict.
100-
let functorSource = `\
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({imports:${h.HIDDEN_IMPORTS},liveVar:${h.HIDDEN_LIVE},onceVar:${h.HIDDEN_ONCE},import:${h.HIDDEN_IMPORT},importMeta:${h.HIDDEN_META}})=>(function(){'use strict';\
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${preamble}\
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${scriptSource}
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})()
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`;
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const functorSource = buildFunctorSource(
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scriptSource,
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sourceOptions,
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sourceUrl,
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);
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107-
if (sourceUrl) {
108-
functorSource += `//# sourceURL=${sourceUrl}\n`;
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}
110-
const moduleAnalysis = freeze({
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exportAlls: freeze(sourceOptions.exportAlls),
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imports: freeze(sourceOptions.imports),
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liveExportMap: freeze(sourceOptions.liveExportMap),
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fixedExportMap: freeze(sourceOptions.fixedExportMap),
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reexportMap: freeze(sourceOptions.reexportMap),
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needsImport: sourceOptions.dynamicImport.present,
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needsImportMeta: sourceOptions.importMeta.present,
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functorSource,
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});
120-
return moduleAnalysis;
51+
return buildModuleRecord(sourceOptions, functorSource);
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};
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123-
export const makeModuleAnalyzer = babel => {
124-
const transformSource = makeTransformSource(makeModulePlugins, babel);
54+
export const makeModuleAnalyzer = () => {
55+
const transformSource = makeTransformSource(makeModulePlugins);
12556
return makeCreateStaticRecord(transformSource);
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};
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128-
export const makeModuleTransformer = (babel, importer) => {
129-
const transformSource = makeTransformSource(makeModulePlugins, babel);
59+
// TODO: May be unused; referenced only in ses/test262
60+
export const makeModuleTransformer = (_babel, importer) => {
61+
const transformSource = makeTransformSource(makeModulePlugins);
13062
const createStaticRecord = makeCreateStaticRecord(transformSource);
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return {
13264
rewrite(ss) {

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