/**
* In dot mode a graphical representation of the internal parse forest <code>root</code> is
* created and the path to the created file is returned. Otherwise a {@link String} representation
* is returned.<br>
* In verbose mode all used rules are printed. Otherwise only the rules defined in the grammar are
* printed.<br>
* In each case ambiguity nodes and <code>nodeWithException</code> are highlighted.
*
* @param root {@link AbstractParseNode} which is the root of the internal parse forest
* @param nodeWithException {@link AbstractParseNode} which caused an exception an will be
* highlighted in the output
* @return {@link String} message as a result of the printing process
*/
private String printParseForest(AbstractParseNode root, AbstractParseNode nodeWithException) {
ParseForest2Output printer =
graphBuilder.isDotMode()
? new ParseForest2Dot(this, graphBuilder.getDotOutputFormat())
: new ParseForest2String(this);
return printer.convertParseForest(
root,
graphBuilder.isVerboseMode(),
graphBuilder.isVerboseMode()
? nodeWithException
: stack.getCurrentElement().getParentApplicationOfDefinedRule().getRepresentedNode());
}
/**
* Executes the semantic actions which can be identified by:
*
* <ul>
* <li>the number of the currently executed rule
* <li>the rule defined in an EDL grammar which was lastly applied before the currently applied
* rule
* <li>the current position in the rule (<code>position</code>)
* </ul>
*
* If an {@link Exception} occurs during the execution of the semantic actions and the debug mode
* is activated then the internal parse forest is printed and the application of rule which caused
* the {@link Exception} is highlighted.
*
* @param root {@link AbstractParseNode} which is the root of the internal parse forest
* @param currentNode {@link AbstractParseNode} the currently traversed node
*/
private void executeSemanticAction(AbstractParseNode root, AbstractParseNode currentNode) {
try {
StackElement currentElement = stack.getCurrentElement();
if (currentElement.getAppliedRule() != null
&& currentElement.getAppliedRule().canHaveSemanticAciton()) {
// if the current element recognizes an input character no
// semantic actions can be defined for that node
graphBuilder.execute(stack);
}
} catch (Throwable e) {
if (graphBuilder.isDebugMode()) {
System.err.println("\tAn error occured: " + e.toString());
System.err.println(printParseForest(root, currentNode));
}
if (e instanceof RuntimeException) {
throw (RuntimeException) e;
} else {
throw new RuntimeException(e);
}
}
}
/**
* Traverses the tree of <code>root</code> via the depth first strategy and executes the
* corresponding semantic actions. If an ambiguity node is found an {@link ParseError} is thrown.
*
* @param root {@link AbstractParseNode} the root of the internal parse forest <code>currentNode
* </code> belongs to
*/
private void traverse(AbstractParseNode root) {
// check if root is an ambiguity node
if (root.isAmbNode()) {
System.out.println("\tAn ambiguity was detected...");
throw new ParseError("An ambiguity was detected.\n" + printParseForest(root));
}
// enter root
stack.enterNode(getRule(root.getLabel()), root, graphBuilder);
executeSemanticAction(root, stack.getCurrentElement().getRepresentedNode());
while (!stack.isEmpty()) {
((GraphBuilderBaseImpl) graphBuilder).addToSizeOfInternalParseForest(1);
if (stack.getCurrentElement().haveAllChildrenBeenHandeled()) {
// leave node
stack.leaveNode();
// return to parent node
stack.returnToNode();
if (stack.isEmpty()) {
break;
}
executeSemanticAction(root, stack.getCurrentElement().getRepresentedNode());
} else {
AbstractParseNode nextChild =
stack
.getCurrentElement()
.getRepresentedNode()
.getChildren()[stack.getCurrentElement().getNumberOfChildren()];
// check if nextChild is an ambiguity node
if (nextChild.isAmbNode()) {
System.out.println("\tAn ambiguity was detected...");
throw new ParseError("An ambiguity was detected.\n" + printParseForest(root));
}
stack.enterNode(getRule(nextChild.getLabel()), nextChild, graphBuilder);
executeSemanticAction(root, stack.getCurrentElement().getRepresentedNode());
}
}
}
