rehype-shiki

rehype plugin to apply syntax highlighting on code blocks with shiki.

This plugin was based upon rehype-highlight.

Installation

npm:

npm install rehype-shiki

Usage

Say example.html looks as follows:

...and example.js like this:

var vfile = require('to-vfile')
var report = require('vfile-reporter')
var rehype = require('rehype')
var shiki = require('rehype-shiki')

rehype()
  .data('settings', {fragment: true})
  .use(shiki)
  .process(vfile.readSync('example.html'), function(err, file) {
    console.error(report(err || file))
    console.log(String(file))
  })

Now, running node example yields:

API

rehype().use(shiki[, options])

Apply syntax highlighting to pre > code using shiki; which tokenises the code block and new hast nodes are subsequently created from (using this plugin).

Configure the language by using the language-foo class on the code element. For example;

<pre><code class="language-js">console.log("Hello world!")</code></pre>

This is in respect to the mdast-util-to-hast code handler.

Shiki does not perform language detection, if unknown, this plugin falls back to the theme's background and text colour (chosen as settings.foreground from the theme file).

options

options.theme

string, default: 'nord' - Name of shiki theme to use, otherwise path to theme file for it to load.

options.useBackground

boolean, default: true - Whether to apply the background theme colour to the pre element.

License

MIT © @rsclarke

#include <algorithm>
#include <memory>
#include <vector>
template <class Key, class Compare = std::less<Key>>
class Set {
 private:
  enum NodeColor { kBlack = 0, kRed = 1 };

  struct Node {
    Key key;
    Node *lc{nullptr}, *rc{nullptr};
    size_t size{0};
    NodeColor color;  // the color of the parent link

    Node(Key key, NodeColor color, size_t size)
        : key(key), color(color), size(size) {}

    Node() = default;
  };

  void destroyTree(Node *root) const {
    if (root != nullptr) {
      destroyTree(root->lc);
      destroyTree(root->rc);
      root->lc = root->rc = nullptr;
      delete root;
    }
  }

  bool is_red(const Node *nd) const {
    return nd == nullptr ? false : nd->color;  // kRed == 1, kBlack == 0
  }

  size_t size(const Node *nd) const { return nd == nullptr ? 0 : nd->size; }

  Node *rotate_left(Node *node) const {
    // left rotate a red link
    //          <1>                   <2>
    //        /    \\               //    \
    //       *      <2>    ==>     <1>     *
    //             /   \          /   \
    //            *     *        *     *
    Node *res = node->rc;
    node->rc = res->lc;
    res->lc = node;
    res->color = node->color;
    node->color = kRed;
    res->size = node->size;
    node->size = size(node->lc) + size(node->rc) + 1;
    return res;
  }

  Node *rotate_right(Node *node) const {
    // right rotate a red link
    //            <1>               <2>
    //          //    \           /    \\
    //         <2>     *   ==>   *      <1>
    //        /   \                    /   \
    //       *     *                  *     *
    Node *res = node->lc;
    node->lc = res->rc;
    res->rc = node;
    res->color = node->color;
    node->color = kRed;
    res->size = node->size;
    node->size = size(node->lc) + size(node->rc) + 1;
    return res;
  }

  NodeColor neg_color(NodeColor n) const { return n == kBlack ? kRed : kBlack; }

  void color_flip(Node *node) const {
    node->color = neg_color(node->color);
    node->lc->color = neg_color(node->lc->color);
    node->rc->color = neg_color(node->rc->color);
  }

  Node *insert(Node *root, const Key &key) const;
  Node *delete_arbitrary(Node *root, Key key) const;
  Node *delete_min(Node *root) const;
  Node *move_red_right(Node *root) const;
  Node *move_red_left(Node *root) const;
  Node *fix_up(Node *root) const;
  const Key &get_min(Node *root) const;
  void serialize(Node *root, std::vector<Key> *) const;
  void print_tree(Set::Node *root, int indent) const;
  Compare cmp_ = Compare();
  Node *root_{nullptr};

 public:
  typedef Key KeyType;
  typedef Key ValueType;
  typedef std::size_t SizeType;
  typedef std::ptrdiff_t DifferenceType;
  typedef Compare KeyCompare;
  typedef Compare ValueCompare;
  typedef Key &Reference;
  typedef const Key &ConstReference;

  Set() = default;

  Set(Set &) = default;

  Set(Set &&) noexcept = default;

  ~Set() { destroyTree(root_); }

  SizeType size() const;

  SizeType count(const KeyType &key) const;

  SizeType erase(const KeyType &key);

  void clear();

  void insert(const KeyType &key);

  bool empty() const;

  std::vector<Key> serialize() const;

  void print_tree() const;
};

template <class Key, class Compare>
typename Set<Key, Compare>::SizeType Set<Key, Compare>::count(
    ConstReference key) const {
  Node *x = root_;
  while (x != nullptr) {
    if (key == x->key) return 1;
    if (cmp_(key, x->key))  // if (key < x->key)
      x = x->lc;
    else
      x = x->rc;
  }
  return 0;
}

template <class Key, class Compare>
typename Set<Key, Compare>::SizeType Set<Key, Compare>::erase(
    const KeyType &key) {
  if (count(key) > 0) {
    if (!is_red(root_->lc) && !(is_red(root_->rc))) root_->color = kRed;
    root_ = delete_arbitrary(root_, key);
    if (root_ != nullptr) root_->color = kBlack;
    return 1;
  } else {
    return 0;
  }
}

template <class Key, class Compare>
void Set<Key, Compare>::clear() {
  destroyTree(root_);
  root_ = nullptr;
}

template <class Key, class Compare>
void Set<Key, Compare>::insert(const KeyType &key) {
  root_ = insert(root_, key);
  root_->color = kBlack;
}

template <class Key, class Compare>
bool Set<Key, Compare>::empty() const {
  return size(root_) == 0;
}

template <class Key, class Compare>
typename Set<Key, Compare>::Node *Set<Key, Compare>::insert(
    Set::Node *root, const Key &key) const {
  if (root == nullptr) return new Node(key, kRed, 1);
  if (root->key == key)
    ;
  else if (cmp_(key, root->key))  // if (key < root->key)
    root->lc = insert(root->lc, key);
  else
    root->rc = insert(root->rc, key);
  return fix_up(root);
}

template <class Key, class Compare>
typename Set<Key, Compare>::Node *Set<Key, Compare>::delete_min(
    Set::Node *root) const {
  if (root->lc == nullptr) {
    delete root;
    return nullptr;
  }
  if (!is_red(root->lc) && !is_red(root->lc->lc)) {
    // make sure either root->lc or root->lc->lc is red
    // thus make sure we will delete a red node in the end
    root = move_red_left(root);
  }
  root->lc = delete_min(root->lc);
  return fix_up(root);
}

template <class Key, class Compare>
typename Set<Key, Compare>::Node *Set<Key, Compare>::move_red_right(
    Set::Node *root) const {
  color_flip(root);
  if (is_red(root->lc->lc)) {  // assume that root->lc != nullptr when calling
                               // this function
    root = rotate_right(root);
    color_flip(root);
  }
  return root;
}

template <class Key, class Compare>
typename Set<Key, Compare>::Node *Set<Key, Compare>::move_red_left(
    Set::Node *root) const {
  color_flip(root);
  if (is_red(root->rc->lc)) {
    // assume that root->rc != nullptr when calling this function
    root->rc = rotate_right(root->rc);
    root = rotate_left(root);
    color_flip(root);
  }
  return root;
}

template <class Key, class Compare>
typename Set<Key, Compare>::Node *Set<Key, Compare>::fix_up(
    Set::Node *root) const {
  if (is_red(root->rc) && !is_red(root->lc))  // fix right leaned red link
    root = rotate_left(root);
  if (is_red(root->lc) &&
      is_red(root->lc->lc))  // fix doubly linked left leaned red link
    // if (root->lc == nullptr), then the second expr won't be evaluated
    root = rotate_right(root);
  if (is_red(root->lc) && is_red(root->rc))
    // break up 4 node
    color_flip(root);
  root->size = size(root->lc) + size(root->rc) + 1;
  return root;
}

template <class Key, class Compare>
const Key &Set<Key, Compare>::get_min(Set::Node *root) const {
  Node *x = root;
  // will crash as intended when root == nullptr
  for (; x->lc != nullptr; x = x->lc)
    ;
  return x->key;
}

template <class Key, class Compare>
typename Set<Key, Compare>::SizeType Set<Key, Compare>::size() const {
  return size(root_);
}

template <class Key, class Compare>
typename Set<Key, Compare>::Node *Set<Key, Compare>::delete_arbitrary(
    Set::Node *root, Key key) const {
  if (cmp_(key, root->key)) {
    // key < root->key
    if (!is_red(root->lc) && !(is_red(root->lc->lc)))
      root = move_red_left(root);
    // ensure the invariant: either root->lc or root->lc->lc (or root and
    // root->lc after dive into the function) is red, to ensure we will
    // eventually delete a red node. therefore we will not break the black
    // height balance
    root->lc = delete_arbitrary(root->lc, key);
  } else {
    // key >= root->key
    if (is_red(root->lc)) root = rotate_right(root);
    if (key == root->key && root->rc == nullptr) {
      delete root;
      return nullptr;
    }
    if (!is_red(root->rc) && !is_red(root->rc->lc)) root = move_red_right(root);
    if (key == root->key) {
      root->key = get_min(root->rc);
      root->rc = delete_min(root->rc);
    } else {
      root->rc = delete_arbitrary(root->rc, key);
    }
  }
  return fix_up(root);
}

template <class Key, class Compare>
std::vector<Key> Set<Key, Compare>::serialize() const {
  std::vector<int> v;
  serialize(root_, &v);
  return v;
}

template <class Key, class Compare>
void Set<Key, Compare>::serialize(Set::Node *root,
                                  std::vector<Key> *res) const {
  if (root == nullptr) return;
  serialize(root->lc, res);
  res->push_back(root->key);
  serialize(root->rc, res);
}

template <class Key, class Compare>
void Set<Key, Compare>::print_tree(Set::Node *root, int indent) const {
  if (root == nullptr) return;
  print_tree(root->lc, indent + 4);
  std::cout << std::string(indent, '-') << root->key << std::endl;
  print_tree(root->rc, indent + 4);
}

template <class Key, class Compare>
void Set<Key, Compare>::print_tree() const {
  print_tree(root_, 0);
}