Markdown.php 4.89 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171
<?php
/**
 * @link http://www.yiiframework.com/
 * @copyright Copyright (c) 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace yii\console;

use yii\helpers\Console;

/**
 * A Markdown parser that enhances markdown for reading in console environments.
 *
 * Based on [cebe/markdown](https://github.com/cebe/markdown).
 *
 * @author Carsten Brandt <mail@cebe.cc>
 * @since 2.0
 */
class Markdown extends \cebe\markdown\Parser
{
    /**
     * @var array these are "escapeable" characters. When using one of these prefixed with a
     * backslash, the character will be outputted without the backslash and is not interpreted
     * as markdown.
     */
    protected $escapeCharacters = [
        '\\', // backslash
        '`', // backtick
        '*', // asterisk
        '_', // underscore
    ];

    /**
     * @inheritDoc
     */
    protected function identifyLine($lines, $current)
    {
        if (isset($lines[$current]) && (strncmp($lines[$current], '```', 3) === 0 || strncmp($lines[$current], '~~~', 3) === 0)) {
            return 'fencedCode';
        }
        return parent::identifyLine($lines, $current);
    }

    /**
     * Consume lines for a fenced code block
     */
    protected function consumeFencedCode($lines, $current)
    {
        // consume until ```
        $block = [
            'type' => 'code',
            'content' => [],
        ];
        $line = rtrim($lines[$current]);
        $fence = substr($line, 0, $pos = strrpos($line, $line[0]) + 1);
        $language = substr($line, $pos);
        if (!empty($language)) {
            $block['language'] = $language;
        }
        for ($i = $current + 1, $count = count($lines); $i < $count; $i++) {
            if (rtrim($line = $lines[$i]) !== $fence) {
                $block['content'][] = $line;
            } else {
                break;
            }
        }
        return [$block, $i];
    }

    /**
     * Renders a code block
     */
    protected function renderCode($block)
    {
        return Console::ansiFormat(implode("\n", $block['content']), [Console::BG_GREY]) . "\n";
    }

    protected function renderParagraph($block)
    {
        return rtrim($this->parseInline(implode("\n", $block['content']))) . "\n";
    }

    /**
     * @inheritDoc
     */
    protected function inlineMarkers()
    {
        return [
            '*'     => 'parseEmphStrong',
            '_'     => 'parseEmphStrong',
            '\\'    => 'parseEscape',
            '`'     => 'parseCode',
            '~~'    => 'parseStrike',
        ];
    }

    /**
     * Parses an inline code span `` ` ``.
     */
    protected function parseCode($text)
    {
        // skip fenced code
        if (strncmp($text, '```', 3) === 0) {
            return [$text[0], 1];
        }
        if (preg_match('/^(`+) (.+?) \1/', $text, $matches)) { // code with enclosed backtick
            return [
                Console::ansiFormat($matches[2], [Console::UNDERLINE]),
                strlen($matches[0])
            ];
        } elseif (preg_match('/^`(.+?)`/', $text, $matches)) {
            return [
                Console::ansiFormat($matches[1], [Console::UNDERLINE]),
                strlen($matches[0])
            ];
        }
        return [$text[0], 1];
    }

    /**
     * Parses empathized and strong elements.
     */
    protected function parseEmphStrong($text)
    {
        $marker = $text[0];

        if (!isset($text[1])) {
            return [$text[0], 1];
        }

        if ($marker == $text[1]) { // strong
            if ($marker == '*' && preg_match('/^[*]{2}((?:[^*]|[*][^*]*[*])+?)[*]{2}(?![*])/s', $text, $matches) ||
                $marker == '_' && preg_match('/^__((?:[^_]|_[^_]*_)+?)__(?!_)/us', $text, $matches)) {

                return [Console::ansiFormat($this->parseInline($matches[1]), Console::BOLD), strlen($matches[0])];
            }
        } else { // emph
            if ($marker == '*' && preg_match('/^[*]((?:[^*]|[*][*][^*]+?[*][*])+?)[*](?![*])/s', $text, $matches) ||
                $marker == '_' && preg_match('/^_((?:[^_]|__[^_]*__)+?)_(?!_)\b/us', $text, $matches)) {
                return [Console::ansiFormat($this->parseInline($matches[1]), Console::ITALIC), strlen($matches[0])];
            }
        }
        return [$text[0], 1];
    }

    /**
     * Parses the strikethrough feature.
     */
    protected function parseStrike($markdown)
    {
        if (preg_match('/^~~(.+?)~~/', $markdown, $matches)) {
            return [
                Console::ansiFormat($this->parseInline($matches[1]), [Console::CROSSED_OUT]),
                strlen($matches[0])
            ];
        }
        return [$markdown[0] . $markdown[1], 2];
    }

    /**
     * Parses escaped special characters.
     */
    protected function parseEscape($text)
    {
        if (isset($text[1]) && in_array($text[1], $this->escapeCharacters)) {
            return [$text[1], 2];
        }
        return [$text[0], 1];
    }
}