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