KTextTemplate::AbstractNodeFactory Class

Detailed Description

This class can be used to make custom tags available to templates. The getNode method should be implemented to return a Node to be rendered.

A node is represented in template markup as content surrounded by percent signed tokens.

text content
{% some_tag arg1 arg2 %}
  text content
{% some_other_tag arg1 arg2 %}
  text content
{% end_some_other_tag %}
text content

It is the responsibility of an **%AbstractNodeFactory** implementation to process the contents of a tag and return a Node implementation from its getNode method.

The getNode method would for example be called with the tagContent "some_tag arg1 arg2". That content could then be split up, the arguments processed and a Node created

Node* SomeTagFactory::getNode(const QString &tagContent, Parser *p) {
  QStringList parts = smartSplit( tagContent );

  parts.removeFirst(); // Remove the "some_tag" part.

  FilterExpression arg1( parts.first(), p );
  FilterExpression arg2( parts.at( 1 ), p );

  return new SomeTagNode( arg1, arg2, p );
}

The getNode implementation might also advance the parser. For example if we had a {% times %} tag which rendered content the amount of times it was given in its argument, it could be used like this:

Some text content.
{% times 5 %}
  the bit to be repeated
{% end_times %}
End text content

The argument to {% times %} might not be a simple number, but could be a FilterExpression such as "someobject.some_property|getDigit:1".

The implementation could look like

Node* SomeOtherTagFactory::getNode(const QString &tagContent, Parser *p) {
  QStringList parts = smartSplit( tagContent );

  parts.removeFirst(); // Remove the "times" part.

  FilterExpression arg( parts.first(), p );

  auto node = new SomeTagNode( arg, p );
  auto childNodes = p->parse( node, "end_times" );
  node->setChildNodes( childNodes );
  p->removeNextToken();

  return node;
}

Note that it is necessary to invoke the parser to create the child nodes only after creating the Node to return. That node must be passed to the Parser to perform as the parent QObject to the child nodes.