CI3中实现使用Laravel的辅助函数dd()

实现步骤如下：

1. 在项目根目录执行 composer require symfony/var-dumper。
2. 在 index.php 里添加 require_once './vendor/autoload.php'; 并且需要加载在 require_once BASEPATH.'core/CodeIgniter.php'; 前面。
3. 访问 Gist ，将文件保存为 helper.php 放在 /application/core 目录下。
4. 在项目根目录的 composer.json 文件的 autoload 字段中将 helper.php 相对于
   composer.json 的路径（和 composer.json 的相对路径）添加上。
5. 在项目中执行 composer dump-auoload。

修改后的 composer.json 的示例：

{
    "description": "The CodeIgniter framework",
    "name": "codeigniter/framework",
    "type": "project",
    "homepage": "https://codeigniter.com",
    "license": "MIT",
    "support": {
        "forum": "http://forum.codeigniter.com/",
        "wiki": "https://github.com/bcit-ci/CodeIgniter/wiki",
        "slack": "https://codeigniterchat.slack.com",
        "source": "https://github.com/bcit-ci/CodeIgniter"
    },
    "require": {
        "php": ">=5.3.7",
        "symfony/var-dumper": "^3.4"
    },
    "autoload": {
        "files": [
            "application/core/helper.php"
        ]
    },
    "suggest": {
        "paragonie/random_compat": "Provides better randomness in PHP 5.x"
    },
    "require-dev": {
        "mikey179/vfsStream": "1.1.*",
        "phpunit/phpunit": "4.* || 5.*"
    }
}

若无法打开 Gist ，helper.php 文件内容如下：

<?php

# install symfony/var-dump to your project
# composer require symfony/var-dumper

// use namespace
use Symfony\Component\VarDumper\Cloner\VarCloner;
use Symfony\Component\VarDumper\Dumper\CliDumper;
use Symfony\Component\VarDumper\Dumper\HtmlDumper as SymfonyHtmlDumper;

/**
 * Class HtmlDumper
 */
class HtmlDumper extends SymfonyHtmlDumper
{
    /**
     * Colour definitions for output.
     *
     * @var array
     */
    protected $styles = [
        'default' => 'background-color:#fff; color:#222; line-height:1.2em; font-weight:normal; font:12px Monaco, Consolas, monospace; word-wrap: break-word; white-space: pre-wrap; position:relative; z-index:100000',
        'num' => 'color:#a71d5d',
        'const' => 'color:#795da3',
        'str' => 'color:#df5000',
        'cchr' => 'color:#222',
        'note' => 'color:#a71d5d',
        'ref' => 'color:#a0a0a0',
        'public' => 'color:#795da3',
        'protected' => 'color:#795da3',
        'private' => 'color:#795da3',
        'meta' => 'color:#b729d9',
        'key' => 'color:#df5000',
        'index' => 'color:#a71d5d',
    ];
}

/**
 * Class Dumper
 */
class Dumper
{
    /**
     * Dump a value with elegance.
     *
     * @param  mixed  $value
     * @return void
     */
    public function dump($value)
    {
        if (class_exists(CliDumper::class)) {
            $dumper = 'cli' === PHP_SAPI ? new CliDumper : new HtmlDumper;
            $dumper->dump((new VarCloner)->cloneVar($value));
        } else {
            var_dump($value);
        }
    }
}

if (! function_exists('dd')) {
    /**
     * Dump the passed variables and end the script.
     *
     * @param  mixed
     * @return void
     */
    function dd(...$args)
    {
        foreach ($args as $x) {
            (new Dumper)->dump($x);
        }
        die(1);
    }
}

if (! function_exists('dda')) {
    /**
     * Dump the passed array variables and end the script.
     *
     * @param  mixed
     * @return void
     */
    function dda(...$args)
    {
        foreach ($args as $x) {
            (new Dumper)->dump($x->toArray());
        }
        die(1);
    }
}