dart_dice_parser 6.0.2

A dart library for parsing dice notation (e.g. "2d6+4"). Supports advantage/disadvantage, exploding die, and other variations.

example/main.dart

import 'dart:convert';
import 'dart:io';
import 'dart:math';

import 'package:args/args.dart';
import 'package:dart_dice_parser/dart_dice_parser.dart';
import 'package:logging/logging.dart';

const defaultStatsNum = 10000;

void main(List<String> arguments) async {
  Logger.root.level = Level.INFO;

  Logger.root.onRecord.listen((rec) {
    if (rec.level > Level.INFO) {
      stderr.writeln(
        '[${rec.level.name.padLeft(7)}] ${rec.loggerName.padLeft(12)}: ${rec.message}',
      );
    } else {
      stdout.writeln(
        '[${rec.level.name.padLeft(7)}] ${rec.loggerName.padLeft(12)}: ${rec.message}',
      );
    }
  });
  Random random = Random.secure();

  final argParser = ArgParser()
    ..addOption(
      "num",
      abbr: "n",
      help: "Number of times to roll the expression",
      defaultsTo: "1",
    )
    ..addOption(
      "output",
      abbr: "o",
      defaultsTo: 'plain',
      help: 'output type',
      allowedHelp: {
        'plain': 'output using RollResult.toString()',
        'json': 'output JSON',
      },
    )
    ..addOption(
      "random",
      abbr: "r",
      defaultsTo: 'pseudo',
      help: "Random number generator to use.",
      allowedHelp: {
        'secure': 'secure random',
        'pseudo': 'pseudorandom generator',
        '<integer>': 'pseudorandom generator initialized with given seed',
      },
      callback: (val) {
        switch (val?.toLowerCase()) {
          case "pseudo":
            random = Random();
          case "secure":
            random = Random.secure();
          default:
            try {
              random = Random(int.parse(val!));
            } on FormatException {
              stderr.writeln("Invalid random number generator '$val'.");
              exit(1);
            }
        }
      },
    )
    ..addFlag(
      "verbose",
      abbr: "v",
      help: "Enable verbose logging",
      callback: (verbose) {
        if (verbose) {
          Logger.root.level = Level.FINEST;
        } else {
          Logger.root.level = Level.INFO;
        }
      },
    )
    ..addFlag(
      "stats",
      abbr: "s",
      help:
          "Output statistics for the given dice expression. Uses n=$defaultStatsNum unless overridden",
    )
    ..addFlag("help", abbr: "h");

  final results = argParser.parse(arguments);
  if (results["help"] as bool) {
    stderr.writeln("Usage:");
    stderr.writeln(argParser.usage);
    exit(1);
  }

  final input = results.rest.join(" ");
  if (input.isEmpty) {
    stderr.writeln("Supply a dice expression. e.g. '2d6+1'");
    exit(1);
  }

  try {
    final collectStats = results['stats'] as bool;
    if (collectStats) {
      random = Random();
    }
    final diceExpr = DiceExpression.create(input, random);

    exit(
      await run(
        expression: diceExpr,
        numRolls: int.parse(results["num"] as String),
        stats: collectStats,
        output: results['output'] as String,
      ),
    );
  } on FormatException catch (e) {
    stderr.writeln(e.toString());
  }
}

Future<int> run({
  required int numRolls,
  required DiceExpression expression,
  required bool stats,
  required String output,
}) async {
  if (stats) {
    final stats =
        await expression.stats(num: numRolls == 1 ? defaultStatsNum : numRolls);
    stdout.writeln(stats);
  } else {
    await for (final r in expression.rollN(numRolls)) {
      if (output == 'json') {
        stdout.writeln(json.encode(r));
      } else {
        stdout.writeln(r);
      }
    }
  }
  return 0;
}