pandoc_filter.module

<?php
/**
 * @file
 * Module file for pandoc_filter.
 */

function pandoc_filter_config_load() {
  if (!class_exists('Pandoc', true)) {
    if (module_exists('composer_manager')
    && function_exists('composer_manager_register_autoloader')) {
      composer_manager_register_autoloader();
    }
    elseif (file_exists(__DIR__ . '/vendor/autoload.php')) {
      require_once __DIR__ . '/vendor/autoload.php';
    }
    else {
      drupal_set_message('Could not find the Pandoc Class.
      Please use composer to grab the Pandoc-PHP library
      or use composer_manager to help you.', 'error');
      return FALSE;
    }
  }
  return TRUE;
}


/**
 * @defgroup pandoc_filter Pandoc Filter
 * @{
 * Pandoc filter for drupal.
*/


/**
 * Implements hook_menu().
 */
function pandoc_filter_menu() {
  $items['admin/config/content'] = array(
    'title' => 'Pandoc Filter',
    'page callback' => '_pandoc_filter_information',
    'access callback' => TRUE,
  );
  return $items;
}

/**
 * Implements hook_help().
 */
function pandoc_filter_help($path, $arg) {
  switch ($path) {
    case 'admin/help#pandoc_filter':
      return _pandoc_filter_information();
  }
}

/**
 * Simply returns a little bit of information about the example.
 */
function _pandoc_filter_information() {
  return t("<p>The Pandoc drupal filter replaces supported markup formats to html
    to be displayed in content pages</p>",
    array('!link' => l(t('admin/config/content/formats'), 'admin/config/content/formats'))
  );
}

/**
 * Implements hook_filter_info().
 *
 */
function pandoc_filter_filter_info() {
  $filters['pandoc_filter'] = array(
    'title' => t('Pandoc Filter'),
    'description' => t('Replaces a specified markup with html'),
    'process callback'  => '_pandoc_filter_filter_process',
    'default settings' => array(
      'input_format'      => 'mediawiki',
      'base_header_level' => '2',
      'columns'           => '72',
      'toc_depth'         => '3',
      'highlight_style'   => 'pygments',
      'css'               => NULL,
      'use_html5'         => FALSE,
      'use_parse_raw'     => FALSE,
      'use_smart'         => FALSE,
      'use_normalize'     => FALSE,
      'use_preserve_tabs' => FALSE,
      'use_toc'           => FALSE,
      'use_no_highlight'  => FALSE,
      'use_section_divs'  => FALSE,
    ),

    'settings callback' => '_pandoc_filter_filter_settings',
    'tips callback' => '_pandoc_filter_filter_tips',
  );
  return $filters;
}


/**
 * Settings callback for Pandoc filter.
 *
 */
function _pandoc_filter_filter_settings($form, $form_state, $filter, $format, $defaults) {
  $settings['input_format'] = array(
    '#type' => 'select',
    '#title' => t('Markup type'),
    '#default_value' => isset($filter->settings['input_format'])
    ? $filter->settings['input_format'] : $defaults['input_format'],
    '#description' => t('The markup type to be used in the filter'),
    '#options' => array(
      'native'            => t('Native Haskell'),
      'json'              => t('JSON native AST'),
      'markdown'          => t('Pandoc Markdown'),
      'markdown_strict'   => t('Strict Pandoc Markdown'),
      'markdown_phpextra' => t('Php Markdown'),
      'markdown_github'   => t('Github extended Markdown'),
      'markdown_mmd'      => t('MultiMarkdown'),
      'rst'               => t('reStructuredText'),
      'mediawiki'         => t('MediaWiki'),
      'docbook'           => t('DocBook'),
      'textile'           => t('Textile'),
      'latex'             => t('LaTeX'),
    ),
  );

  $settings['use_html5'] = array(
    '#title' => t('Use html5 tags in output'),
    '#type' => 'checkbox',
    '#default_value' => isset($filter->settings['use_html5'])
    ? $filter->settings['use_html5'] : $defaults['use_html5'],
  );

  $settings['use_parse_raw'] = array(
    '#title' => t('Parse untranslatable HTML codes and LaTeX enviroments as raw'),
    '#type' => 'checkbox',
    '#default_value' => isset($filter->settings['use_parse_raw'])
    ? $filter->settings['use_parse_raw'] : $defaults['use_parse_raws_raw'],
  );

  $settings['use_smart'] = array(
    '#title' => t('Automatically produce typographically correct output'),
    '#type' => 'checkbox',
    '#default_value' => isset($filter->settings['use_smart'])
    ? $filter->settings['use_smart'] : $defaults['use_smart'],
  );

  $settings['use_preserve_tabs'] = array(
    '#title' => t('Preserve tabs in formatting for code blocks'),
    '#type' => 'checkbox',
    '#default_value' => isset($filter->settings['use_preserve_tabs'])
    ? $filter->settings['use_preserve_tabs'] : $defaults['use_preserve_tabs'],
  );

  $settings['use_normalize'] = array(
    '#title' => t('Normalize document after processing'),
    '#type' => 'checkbox',
    '#default_value' => isset($filter->settings['use_normalize'])
    ? $filter->settings['use_normalize'] : $defaults['use_normalize'],
  );

  $settings['use_toc'] = array(
    '#title' => t('Include a table of contents at the top of the page'),
    '#type' => 'checkbox',
    '#default_value' => isset($filter->settings['use_toc'])
    ? $filter->settings['use_toc'] : $defaults['use_toc'],
  );

  $settings['use_no_highlight'] = array(
    '#title' => t('Disables code highlighting'),
    '#type' => 'checkbox',
    '#default_value' => isset($filter->settings['use_no_highlight'])
    ? $filter->settings['use_no_highlight'] : $defaults['use_no_highlight'],
  );

  $settings['use_section_divs'] = array(
    '#title' => t('Wrap sections in div tags (or section with html5 enabled)'),
    '#type' => 'checkbox',
    '#default_value' => isset($filter->settings['use_section_divs'])
    ? $filter->settings['use_section_divs'] : $defaults['use_section_divs'],
  );

  $settings['base_header_level'] = array(
    '#type' => 'select',
    '#title' => t('Base header level'),
    '#default_value' => isset($filter->settings['base_header_level'])
    ? $filter->settings['base_header_level'] : $defaults['base_header_level'],
    '#description' => t('The header tag to use for the top level titles'),
    '#options' => array(
      '1' => t('1'),
      '2' => t('2'),
      '3' => t('3'),
      '4' => t('4'),
      '5' => t('5'),
      '6' => t('6'),
    ),
  );

  $settings['columns'] = array(
    '#type' => 'textfield',
    '#title' => t('Column width'),
    '#default_value' => isset($filter->settings['columns'])
    ? $filter->settings['columns'] : $defaults['columns'],
    '#description' => t('A positive integer that determines the number of characters per line on output'),
    '#element_validate' => array('element_validate_integer_positive'),
    '#width' => '20px',
    '#maxlength' => 3,
  );

  $settings['toc_depth'] = array(
    '#type' => 'select',
    '#title' => t('Table of contents depth'),
    '#default_value' => isset($filter->settings['toc_depth'])
    ? $filter->settings['toc_depth'] : $defaults['toc_depth'],
    '#description' => t('The number of header levels below the base to include in the table of contents'),
    '#options' => array(
      '1' => t('1'),
      '2' => t('2'),
      '3' => t('3'),
      '4' => t('4'),
      '5' => t('5'),
      '6' => t('6'),
    ),
  );

  $settings['highlight_style'] = array(
    '#type' => 'select',
    '#title' => t('Code highlight style'),
    '#default_value' => isset($filter->settings['highlight_style'])
    ? $filter->settings['highlight_style'] : $defaults['highlight_style'],
    '#description' => t('The highlight style to be used in fenced code blocks'),
    '#options' => array(
      'pygments'   => t('pygments'),
      'kate'       => t('kate'),
      'monochrome' => t('monochrome'),
      'espresso'   => t('expresso'),
      'zenburn'    => t('zenburn'),
      'haddock'    => t('haddock'),
      'tango'      => t('tango'),
    ),
  );

  $form['description'] = array(
    '#type' => 'item',
    '#title' => t('See the <a href="http://pandoc.org/README.html">Pandoc readme</a> for more details'),
  );

  return $settings;
}


function pandoc_filter_check_settings($element, $filter, $default) {
  $value = isset($filter->settings[$element]) ? $filter->settings[$element] : $default;
  return $value;
}


/**
 * Pandoc filter process callback.
 *
 */
function _pandoc_filter_filter_process($text, $filter, $format) {

  $loaded = pandoc_filter_config_load();
  if(!$loaded){
    return $text;
  }

  // Creates a new Pandoc object from pandoc-php
  $pandoc = New Pandoc\Pandoc();

  // This array will store key value pairs that will be passed to the
  // runWith pandoc-php function and match options for Pandoc
  $options = array();

  $options['from']  = pandoc_filter_check_settings('input_format', $filter, 'mediawiki');

  if(pandoc_filter_check_settings('use_html5', $filter, FALSE) == TRUE) {
    $options['to'] = 'html5';
  }
  else {
    $options['to'] = 'html';
  }

  if(pandoc_filter_check_settings('use_parse_raw', $filter, FALSE) == TRUE)
    $options['parse-raw']     = NULL;
  if(pandoc_filter_check_settings('use_smart', $filter, FALSE) == TRUE)
    $options['smart']         = NULL;
  if(pandoc_filter_check_settings('use_normalize', $filter, FALSE) == TRUE)
    $options['normalize']     = NULL;
  if(pandoc_filter_check_settings('use_preserve_tabs', $filter, FALSE) == TRUE)
    $options['preserve-tabs'] = NULL;
  if(pandoc_filter_check_settings('use_toc', $filter, FALSE) == TRUE)
    $options['toc']           = NULL;
  if(pandoc_filter_check_settings('use_no_highlight', $filter, FALSE) == TRUE)
    $options['no-highlight']  = NULL;
  if(pandoc_filter_check_settings('use_section_divs', $filter, FALSE) == TRUE)
    $options['section-divs']  = NULL;

  $options['base-header-level'] = pandoc_filter_check_settings('base_header_level', $filter, 2);
  $options['columns'] = pandoc_filter_check_settings('columns', $filter, 72);
  $options['toc-depth']         = pandoc_filter_check_settings('toc_depth', $filter, 3);
  $options['highlight-style']   = pandoc_filter_check_settings('highlight-style', $filter, 'pygments');

  $text = $pandoc->runWith($text, $options);

  return $text;
}


/**
 * Filter tips callback for Pandoc filter.
 *
 */
function _pandoc_filter_filter_tips($filter, $format, $long = FALSE) {
  $replacement = isset($filter->settings['input_format'])
  ? $filter->settings['input_format'] : 'mediawiki';
  if (!$long) {
    // This string will be shown in the content add/edit form.
    return t('Content in the %replacement format will be converted to html.', array('%replacement' => $replacement));
  }
  else {
    return t('Content in the %replacement format will be converted to html through the pandoc program.',
    array('%replacement' => $replacement));
  }
}

/**
 * @} End of "defgroup pandoc_filter".
 */