Files F100650860

Scope.js
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Created: Sat, Feb 1, 12:51

Scope.js
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	import extractNames from './extractNames.js';
	import reserved from '../utils/reserved.js';

	export default function Scope(options) {
	options = options \|\| {};

	this.parent = options.parent;
	this.isBlockScope = !!options.block;
	this.createDeclarationCallback = options.declare;

	let scope = this;
	while (scope.isBlockScope) scope = scope.parent;
	this.functionScope = scope;

	this.identifiers = [];
	this.declarations = Object.create(null);
	this.references = Object.create(null);
	this.blockScopedDeclarations = this.isBlockScope ? null : Object.create(null);
	this.aliases = Object.create(null);
	}

	Scope.prototype = {
	addDeclaration(node, kind) {
	for (const identifier of extractNames(node)) {
	const name = identifier.name;

	const declaration = { name, node: identifier, kind, instances: [] };
	this.declarations[name] = declaration;

	if (this.isBlockScope) {
	if (!this.functionScope.blockScopedDeclarations[name])
	this.functionScope.blockScopedDeclarations[name] = [];
	this.functionScope.blockScopedDeclarations[name].push(declaration);
	}
	}
	},

	addReference(identifier) {
	if (this.consolidated) {
	this.consolidateReference(identifier);
	} else {
	this.identifiers.push(identifier);
	}
	},

	consolidate() {
	for (let i = 0; i < this.identifiers.length; i += 1) {
	// we might push to the array during consolidation, so don't cache length
	const identifier = this.identifiers[i];
	this.consolidateReference(identifier);
	}

	this.consolidated = true; // TODO understand why this is necessary... seems bad
	},

	consolidateReference(identifier) {
	const declaration = this.declarations[identifier.name];
	if (declaration) {
	declaration.instances.push(identifier);
	} else {
	this.references[identifier.name] = true;
	if (this.parent) this.parent.addReference(identifier);
	}
	},

	contains(name) {
	return (
	this.declarations[name] \|\|
	(this.parent ? this.parent.contains(name) : false)
	);
	},

	createIdentifier(base) {
	if (typeof base === 'number') base = base.toString();

	base = base
	.replace(/\s/g, '')
	.replace(/\[([^\]]+)\]/g, '_$1')
	.replace(/[^a-zA-Z0-9_$]/g, '_')
	.replace(/_{2,}/, '_');

	let name = base;
	let counter = 1;

	while (
	this.declarations[name] \|\|
	this.references[name] \|\|
	this.aliases[name] \|\|
	name in reserved
	) {
	name = `${base}$${counter++}`;
	}

	this.aliases[name] = true;
	return name;
	},

	createDeclaration(base) {
	const id = this.createIdentifier(base);
	this.createDeclarationCallback(id);
	return id;
	},

	findDeclaration(name) {
	return (
	this.declarations[name] \|\|
	(this.parent && this.parent.findDeclaration(name))
	);
	},

	// Sometimes, block scope declarations change name during transpilation
	resolveName(name) {
	const declaration = this.findDeclaration(name);
	return declaration ? declaration.name : name;
	}
	};

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