persistence.antlr.TreeBlockContext Maven / Gradle / Ivy
package persistence.antlr;
/* ANTLR Translator Generator
* Project led by Terence Parr at http://www.jGuru.com
* Software rights: http://www.antlr.org/license.html
*
*/
/**The context needed to add root,child elements to a Tree. There
* is only one alternative (i.e., a list of children). We subclass to
* specialize. MakeGrammar.addElementToCurrentAlt will work correctly
* now for either a block of alts or a Tree child list.
*
* The first time addAlternativeElement is called, it sets the root element
* rather than adding it to one of the alternative lists. Rather than have
* the grammar duplicate the rules for grammar atoms etc... we use the same
* grammar and same refToken behavior etc... We have to special case somewhere
* and here is where we do it.
*/
class TreeBlockContext extends BlockContext {
protected boolean nextElementIsRoot = true;
public void addAlternativeElement(AlternativeElement e) {
TreeElement tree = (TreeElement)block;
if (nextElementIsRoot) {
tree.root = (GrammarAtom)e;
nextElementIsRoot = false;
}
else {
super.addAlternativeElement(e);
}
}
}