Rolling the Dice | Lupe Code

Be me, someone whom like to play pen-and-paper RPGs, like Dungeons & Dragons or GURPS.

Also, be me, avid computer programmer.

I’ve created dice rolling programs in quite a few languages, C#, Java, and a few others.

Being a web programmer, my strongest language is PHP. I also needed to learn the workings of Symfony Console, a PHP package that let’s you run PHP applications in the console.

The rolling of the dice was pretty strait forward:

public static function rollOne(int $sides)

{

return (random_int(1, $sides));

}

Cool, so now we can roll a variable-sided die. But how do we get it to work in the console?

We first need to set up our application in Composer, using a composer.json file like so:

{
    "require": {
        "symfony/console": "^3.3"
    },
    "autoload": {
        "psr-4": {
            "Dice\\": "src/"
        }
    }
}

{

"require": {

"symfony/console": "^3.3"

"autoload": {

"psr-4": {

"Dice\\": "src/"

}

After we install everything, we can start using the Symfony application methods.

I’m going to create a file called dice. No extension, just dice.

#!/usr/bin/env php

<?php 

require_once __DIR__ . '/vendor/autoload.php';

use Dice\RollCommand;
use Symfony\Component\Console\Application;

$app = new Application();

$app->add(new RollCommand());

$app->run();

#!/usr/bin/env php

<?php

require_once __DIR__ . '/vendor/autoload.php';

use Dice\RollCommand;

use Symfony\Component\Console\Application;

$app = new Application();

$app->add(new RollCommand());

$app->run();

I’m going to have two classes, the RollCommand and Dice. I’ve specified in the composer.json file that my code will be in the src folder, so I will create the classes there.

Here’s the first version of those classes I wrote:

<?php

namespace Dice;

use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\Input\InputArgument;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Input\InputOption;
use Symfony\Component\Console\Output\OutputInterface;

class RollCommand extends Command
{

    protected function configure()
    {
        $this->setName("Roll")
             ->setDescription("Rolls fair dice.")
             ->addArgument('Dice String', InputArgument::REQUIRED, 'e.g.: 2d6, 1d20+4')
        ;
    }

    protected function execute(InputInterface $input, OutputInterface $output)
    {
        $dice    = new Dice();
        $matches = [];
        preg_match('/(\d+)d(\d+)\+?(\d)?/i', $input->getArgument('Dice String'), $matches);
        $modifier = empty($matches[3]) ? 0 : (int)$matches[3];
        $roll = $dice::roll((int)$matches[1], (int)$matches[2]);
        $output->writeln('Your roll without modifier was ' . array_sum($roll) . ' [' . implode('|', $roll) . '] + ' . $modifier . ' for a total of ' . (array_sum($roll) + $modifier));
    }

}

<?php

namespace Dice;

use Symfony\Component\Console\Command\Command;

use Symfony\Component\Console\Input\InputArgument;

use Symfony\Component\Console\Input\InputInterface;

use Symfony\Component\Console\Input\InputOption;

use Symfony\Component\Console\Output\OutputInterface;

class RollCommand extends Command

{

protected function configure()

{

$this->setName("Roll")

->setDescription("Rolls fair dice.")

->addArgument('Dice String', InputArgument::REQUIRED, 'e.g.: 2d6, 1d20+4')

;

}

protected function execute(InputInterface $input, OutputInterface $output)

{

$dice = new Dice();

$matches = [];

preg_match('/(\d+)d(\d+)\+?(\d)?/i', $input->getArgument('Dice String'), $matches);

$modifier = empty($matches[3]) ? 0 : (int)$matches[3];

$roll = $dice::roll((int)$matches[1], (int)$matches[2]);

$output->writeln('Your roll without modifier was ' . array_sum($roll) . ' [' . implode('|', $roll) . '] + ' . $modifier . ' for a total of ' . (array_sum($roll) + $modifier));

}

<?php

namespace Dice;

class Dice
{
    public static function rollOne(int $sides)
    {
        return (random_int(1, $sides));
    }

    public static function roll(int $number, int $sides)
    {
        $rolls = [];
        for ($i = 0; $i < $number; $i++) {
            $rolls[] = self::rollOne($sides);
        }

        return $rolls;
    }
}

<?php

namespace Dice;

class Dice

{

public static function rollOne(int $sides)

{

return (random_int(1, $sides));

}

public static function roll(int $number, int $sides)

{

$rolls = [];

for ($i = 0; $i < $number; $i++) {

$rolls[] = self::rollOne($sides);

}

return $rolls;

}

Sweet, let’s test that.

$ php dice Roll 1d6

Your roll without modifier was 1 [1] + 0 for a total of 1

$ php dice Roll 2d8+2

Your roll without modifier was 11 [3|8] + 2 for a total of 13

$ php dice Roll 1d6

Your roll without modifier was 1 [1] + 0 for a total of 1

$ php dice Roll 2d8+2

Your roll without modifier was 11 [3|8] + 2 for a total of 13

That works well! We know what the unmodified roll was, and what each die rolled. Information that is sometimes important, as with critical rolls.

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