1 files changed, 195 insertions, 0 deletions
diff --git a/js/lib/node.js b/js/lib/node.js
new file mode 100644
index 0000000..f96d65c
--- /dev/null
+++ b/js/lib/node.js
@@ -0,0 +1,195 @@
+util = require('util');
+
+function isContainer(node) {
+  var t = node.t;
+  return (t == 'Document' ||
+          t == 'BlockQuote' ||
+          t == 'List' ||
+          t == 'ListItem' ||
+          t == 'Paragraph' ||
+          t == 'Header' ||
+          t == 'Emph' ||
+          t == 'Strong' ||
+          t == 'Link' ||
+          t == 'Image');
+}
+
+function NodeWalker(root) {
+  this.current = root;
+  this.root = root;
+  this.entering = true;
+}
+
+NodeWalker.prototype.resumeAt = function(node, entering) {
+  this.current = node;
+  this.entering = (entering === true);
+};
+
+NodeWalker.prototype.next = function(){
+  var cur = this.current;
+  var entering = this.entering;
+
+  if (!cur)
+    return null;
+
+  var container = isContainer(cur);
+
+  if (entering && container) {
+    if (cur.firstChild) {
+      this.current = cur.firstChild;
+      this.entering = true;
+    } else {
+      // stay on node but exit
+      this.entering = false;
+    }
+
+  } else if (!entering && cur == this.root) {
+    // don't move past root
+    this.current = null;
+
+  } else if (cur.next) {
+    this.current = cur.next;
+    this.entering = true;
+
+  } else {
+    this.current = cur.parent;
+    this.entering = false;
+  }
+
+  return {entering: entering, node: cur};
+};
+
+function Node(nodeType) {
+  this.t = nodeType;
+  this.parent = null;
+  this.firstChild = null;
+  this.lastChild = null;
+  this.prev = null;
+  this.next = null;
+  this.pos = {};
+}
+
+Node.prototype.isContainer = function() {
+  return isContainer(this);
+};
+
+Node.prototype.appendChild = function(child) {
+  child.unlink();
+  child.parent = this;
+  if (this.lastChild) {
+    this.lastChild.next = child;
+    child.prev = this.lastChild;
+    this.lastChild = child;
+  } else {
+    this.firstChild = child;
+    this.lastChild = child;
+  }
+};
+
+Node.prototype.prependChild = function(child) {
+  child.unlink();
+  child.parent = this;
+  if (this.firstChild) {
+    this.firstChild.prev = child;
+    child.next = this.firstChild;
+    this.firstChild = child;
+  } else {
+    this.firstChild = child;
+    this.lastChild = child;
+  }
+};
+
+Node.prototype.unlink = function() {
+  if (this.prev) {
+    this.prev.next = this.next;
+  } else if (this.parent) {
+    this.parent.firstChild = this.next;
+  }
+  if (this.next) {
+    this.next.prev = this.prev;
+  } else if (this.parent) {
+    this.parent.lastChild = this.prev;
+  }
+  this.parent = null;
+  this.next = null;
+  this.prev = null;
+};
+
+Node.prototype.insertAfter = function(sibling) {
+  sibling.unlink();
+  sibling.next = this.next;
+  if (sibling.next) {
+      sibling.next.prev = sibling;
+  }
+  sibling.prev = this;
+  this.next = sibling;
+  sibling.parent = this.parent;
+  if (!sibling.next) {
+    sibling.parent.lastChild = sibling;
+  }
+};
+
+Node.prototype.insertBefore = function(sibling) {
+  sibling.unlink();
+  sibling.prev = this.prev;
+  if (sibling.prev) {
+    sibling.prev.next = sibling;
+  }
+  sibling.next = this;
+  this.prev = sibling;
+  sibling.parent = this.parent;
+  if (!sibling.prev) {
+    sibling.parent.firstChild = sibling;
+  }
+};
+
+Node.prototype.walker = function() {
+  var walker = new NodeWalker(this);
+  return walker;
+};
+
+Node.prototype.toAST = function() {
+  var children;
+  var cur;
+  var result = { t: this.t };
+
+  var propsToShow = ['t', 'c', 'list_data', 'string_content',
+                     'pos', 'start_column', 'end_column',
+                     'tight', 'info'];
+
+  for (var i = 0; i < propsToShow.length; i++) {
+      var prop = propsToShow[i];
+      if (this[prop] !== undefined) {
+          result[prop] = this[prop];
+      }
+  }
+
+  if (isContainer(this)) {
+    children = [];
+    if (this.firstChild) {
+      cur = this.firstChild;
+      while (cur) {
+        // TODO avoid recursion here...
+        children.push(cur.toAST());
+        cur = cur.next;
+      }
+      result.children = children;
+    }
+  }
+  return result;
+
+};
+
+module.exports = Node;
+
+
+/* Example of use of walker:
+
+ var walker = w.walker();
+ var event;
+
+ while (event = walker.next()) {
+   console.log(event.entering, event.node.t);
+ }
+
+*/