mirror of
https://github.com/denoland/deno.git
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133 lines
3.4 KiB
TypeScript
133 lines
3.4 KiB
TypeScript
// Copyright 2018 the Deno authors. All rights reserved. MIT license.
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import * as msg from "gen/msg_generated";
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import * as flatbuffers from "./flatbuffers";
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import { assert } from "./util";
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import * as deno from "./deno";
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import { close } from "./files";
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import * as dispatch from "./dispatch";
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import { exit } from "./os";
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import { globalEval } from "./global_eval";
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const window = globalEval("this");
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function startRepl(historyFile: string): number {
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const builder = flatbuffers.createBuilder();
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const historyFile_ = builder.createString(historyFile);
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msg.ReplStart.startReplStart(builder);
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msg.ReplStart.addHistoryFile(builder, historyFile_);
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const inner = msg.ReplStart.endReplStart(builder);
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const baseRes = dispatch.sendSync(builder, msg.Any.ReplStart, inner);
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assert(baseRes != null);
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assert(msg.Any.ReplStartRes === baseRes!.innerType());
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const innerRes = new msg.ReplStartRes();
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assert(baseRes!.inner(innerRes) != null);
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const rid = innerRes.rid();
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return rid;
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}
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// @internal
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export async function readline(rid: number, prompt: string): Promise<string> {
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const builder = flatbuffers.createBuilder();
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const prompt_ = builder.createString(prompt);
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msg.ReplReadline.startReplReadline(builder);
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msg.ReplReadline.addRid(builder, rid);
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msg.ReplReadline.addPrompt(builder, prompt_);
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const inner = msg.ReplReadline.endReplReadline(builder);
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const baseRes = await dispatch.sendAsync(
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builder,
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msg.Any.ReplReadline,
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inner
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);
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assert(baseRes != null);
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assert(msg.Any.ReplReadlineRes === baseRes!.innerType());
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const innerRes = new msg.ReplReadlineRes();
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assert(baseRes!.inner(innerRes) != null);
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const line = innerRes.line();
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assert(line !== null);
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return line || "";
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}
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// @internal
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export async function replLoop(): Promise<void> {
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window.deno = deno; // FIXME use a new scope (rather than window).
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const historyFile = "deno_history.txt";
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const rid = startRepl(historyFile);
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let code = "";
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while (true) {
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try {
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code = await readBlock(rid, "> ", " ");
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} catch (err) {
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if (err.message === "EOF") {
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break;
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}
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console.error(err);
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exit(1);
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}
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if (!code) {
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continue;
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} else if (code.trim() === ".exit") {
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break;
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}
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evaluate(code);
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}
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close(rid);
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}
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function evaluate(code: string): void {
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try {
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const result = eval.call(window, code); // FIXME use a new scope.
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console.log(result);
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} catch (err) {
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if (err instanceof Error) {
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console.error(`${err.constructor.name}: ${err.message}`);
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} else {
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console.error("Thrown:", err);
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}
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}
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}
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async function readBlock(
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rid: number,
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prompt: string,
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continuedPrompt: string
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): Promise<string> {
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let code = "";
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do {
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code += await readline(rid, prompt);
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prompt = continuedPrompt;
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} while (parenthesesAreOpen(code));
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return code;
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}
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// modified from
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// https://codereview.stackexchange.com/a/46039/148556
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function parenthesesAreOpen(code: string): boolean {
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const parentheses = "[]{}()";
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const stack = [];
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for (const ch of code) {
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const bracePosition = parentheses.indexOf(ch);
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if (bracePosition === -1) {
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// not a paren
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continue;
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}
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if (bracePosition % 2 === 0) {
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stack.push(bracePosition + 1); // push next expected brace position
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} else {
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if (stack.length === 0 || stack.pop() !== bracePosition) {
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return false;
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}
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}
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}
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return stack.length > 0;
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}
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