prototype-3x5/notcl.js

/**
 * @typedef {Notcl.Command[]} Notcl.Script
 * @typedef {Notcl.Word[]} Notcl.Command
 * @typedef {object} Notcl.Word
 * @property {string} text
 */

var Notcl = (() => {
  const InterCommandWhitespace = Peg.Regex(/[^\S\n;]*/y);

  const Comment = Peg.Regex(/#.*\n/y);

  const PreWordWhitespace = Peg.Regex(/[^\S\n;]*/y);

  const BasicWord = Peg.Map(Peg.Regex(/[^\s;]+/y), ([word]) => ({
    text: word,
  }));

  const Word = Peg.Map(
    Peg.Sequence(PreWordWhitespace, BasicWord),
    ([_, word]) => word
  );

  return {
    /**
     * Parse out a Notcl script into an easier-to-interpret representation.
     * No script is actually executed yet.
     *
     * @param {string} code
     * @returns Script
     */
    parse(code) {
      /* Preprocess */
      // fold line endings
      code = code.replace(/(?<!\\)((\\\\)*)\\\n/g, "$1");

      /* Parse */
      function nextWord(/* TODO: null/]/" terminator */) {
        // TODO: handle all kinds of brace/substitution stuff
        const [word, nextIndex] = Word(code, 0) ?? [null, 0];
        if (word) {
          code = code.substring(nextIndex);
          return word;
        } else {
          return null;
        }
      }

      function nextCommand(/* TODO: null/]/" terminator */) {
        const command = /** @type {Notcl.Word[]} */ ([]);
        while (true) {
          // Strip whitespace
          code = code.replace(/^\s*/, "");
          // Strip comments
          if (code[0] == "#") {
            code = code.replace(/^.*\n/, "");
            continue;
          }
          // Strip semicolons
          if (code[0] == ";") {
            code = code.substring(1);
            continue;
          }
          break;
        }

        while (true) {
          const word = nextWord();
          if (word) {
            command.push(word);
            continue;
          }
          break;
        }

        return command;
      }

      /* Loop through commands, with safety check */
      const script = /** @type {Notcl.Command[]} */ ([]);
      for (let i = 0; i < 1000 && code != ""; i++) {
        script.push(nextCommand());
      }

      return script;
    },
  };
})();