100 lines
2.3 KiB
JavaScript
100 lines
2.3 KiB
JavaScript
import {Globals} from './globals';
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import {TypeMap} from './types';
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class Context extends Map {
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add(key, value) {
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this.set(key, value);
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}
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renderStepsUntilNow(steps, step) {
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const stepsUntilNow = steps.slice(0, steps.indexOf(step));
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return TypeMap.renderSteps(stepsUntilNow);
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}
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traverse(steps) {
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return this.traverseAndDo(steps, (node, step) => {
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return this.traverseOneStep(steps, node, step);
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});
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}
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traverseAndDo(steps, fn) {
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const [first, ...rest] = steps;
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if ('key' !== first.type) {
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throw new TypeError(`First step in a traversal must be type "key"`);
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}
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return rest.reduce((walk, step, index) => {
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if (walk instanceof Promise) {
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return walk.then((walk) => {
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fn(walk, step, index);
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});
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}
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else {
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return fn(walk, step, index);
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}
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}, this.get(first.key));
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}
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traverseAndSet(steps, value) {
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return this.traverseAndDo(steps, (node, step, index) => {
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const isLastStep = index === steps.length - 2;
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if (!isLastStep) {
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return this.traverseOneStep(steps, node, step);
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}
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switch (step.type) {
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case 'key':
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return node[step.key] = value.get(this);
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case 'invoke':
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const rendered = this.renderStepsUntilNow(steps, step);
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throw new ReferenceError(`invalid assignment to function "${rendered}"`);
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}
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});
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}
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traverseOneStep(steps, node, step) {
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if ('undefined' === typeof node) {
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const rendered = this.renderStepsUntilNow(steps, step);
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throw TypeError(`"${rendered}" is traversed through but undefined`);
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}
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switch (step.type) {
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case 'key':
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return node[step.key];
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case 'invoke':
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return node(...step.args.map((arg) => arg.get(this)));
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}
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}
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}
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class TypedContext extends Context {
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constructor(iterator) {
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super(iterator);
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this.types = {};
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}
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add(key, value, type) {
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super.add(key, value);
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if (!type) {
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return;
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}
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this.types = {
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...this.types,
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[key]: type,
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};
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}
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}
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export function createContext() {
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const context = new Context();
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context.add('global', new Globals());
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return context;
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}
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export function createTypedContext() {
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const context = new TypedContext();
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context.add('global', new Globals(), 'globals');
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return context;
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}
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