eggtended-js/lib/repl/extensions.js

A extended version of the Egg programming language from the Eloquent Javascript book.

const process = require("process");
const fs = require("fs");

const { SpecialForms } = require("../interp/registry.js");
const { TopEnv } = require("../interp/environment.js");
const { Eggvm } = require("../interp/eggvm.js");

const colors = require("./colors.js");

// PROMPT

TopEnv["__PROMPT__"] = "> ";

const getPromptLine = () => {
  return `${colors.YELLOW} ${TopEnv["__PROMPT__"]} ${colors.DEFAULT}`;
};

// Extra methods

const eggExit = (TopEnv["exit"] = () => {
  console.log(colors.BLUE + "Closing the REPL... Bye!" + colors.DEFAULT);
  process.exit(0);
});

const HELP = [
  `${colors.BLUE} help() ${colors.DEFAULT} show this help menu`,
  `${colors.RED} exit() | Ctrl-D ${colors.DEFAULT} close the REPL`,
  `${colors.GREEN} run() ${colors.DEFAULT} execute a .egg file`,
  `${colors.YELLOW} clear() ${colors.DEFAULT} clear the console`
];

const eggHelp = (TopEnv["help"] = () => {
  console.log(" Egg help menu:");
  HELP.forEach(line => {
    console.log(line);
  });

  return "-".repeat(HELP[0].length - 10);
});

const eggInfo = (TopEnv["info"] = () => {
  console.log(
    colors.BLUE +
      `
                   _                 _          _
                  | |               | |        | |
   ___  __ _  __ _| |_ ___ _ __   __| | ___  __| |
  / _ \\/ _\` |/ _\` | __/ _ \\ '_ \\ / _\` |/ _ \\/ _\` |
 |  __/ (_| | (_| | ||  __/ | | | (_| |  __/ (_| |
  \\___|\\__, |\\__, |\\__\\___|_| |_|\\__,_|\\___|\\__,_|
        __/ | __/ |
       |___/ |___/
` +
      colors.DEFAULT
  );
  console.log(`Version ${TopEnv["__VERSION__"]}`);
  console.log(`Created by David Afonso Dorta. License: ${TopEnv["__LICENSE__"]}`);
});

const eggClear = (TopEnv["clear"] = () => {
  console.log("\u001B[2J\u001B[0;0f");
  eggInfo();
});

const eggVersion = (TopEnv[
  "__VERSION__"
] = require("../../package.json").version);

const eggLicense = (TopEnv["__LICENSE__"] = require("../../package.json").license);

const eggRun = (TopEnv["run"] = (file, debug) => {
  if (debug) {
    console.log(fs.readFileSync(file, "utf8"));
  }

  Eggvm.runFromFile(file);
});

const eggCompleter = (line, env) => {
  // Test if get hits from current directory
  let hits = dirHits(line);

  // Show hits from the REPL variables
  if (hits.length === 0) {
    const word = line.split(/[\s(),"]+/).slice(-1)[0];
    hits = _filter(Object.keys(SpecialForms).concat(_allProperties(env)), word);
  }

  return [hits, line];
};

const _allProperties = obj => {
  let keys = [];

  let proto = obj;
  while (proto) {
    keys = keys.concat(Object.keys(proto));
    proto = Object.getPrototypeOf(proto);
  }

  return keys;
};

const dirHits = line => {
  const match = line.match(/(?:run)\((.*)/);
  if (match) {
    const path = match[1]
      .replace(/["'`]/, "")
      .trim()
      .split("/");
    const dirPath = path.slice(0, -1);
    const filePath = path.slice(-1);

    try {
      return _filter(fs.readdirSync(`./${dirPath}`), filePath);
    } catch (err) {
      return [];
    }
  }

  return [];
};

const _filter = (hits, word) => {
  return hits.filter(hit => {
    return hit.indexOf(word) === 0;
  });
};

module.exports = {
  getPromptLine,
  eggExit,
  eggHelp,
  eggInfo,
  eggClear,
  eggVersion,
  eggLicense,
  eggRun,
  eggCompleter
};