LVParseTree_CreateIteratorBegin and
LVParseTree_CreateIteratorEnd
LVParseTree_CreateIteratorBegin and LVParseTree_CreateIteratorEnd provide iterators for visiting every
node in the tree in a top-to-bottom, left-to-right descent. It is also the basis for the Tag and Terminal
iterators.
Functions
- H_PARSE_TREE_ITR LVParseTree_CreateIteratorBegin(H_PARSE_TREE Tree)
- H_PARSE_TREE_ITR LVParseTree_CreateIteratorEnd(H_PARSE_TREE Tree)
Parameter
Tree
Handle to a parse tree.
Example
The following code prints out every node in a parse tree.
H_PARSE_TREE_ITR Itr;
H_PARSE_TREE_ITR End;
H_PARSE_TREE_NODE Node;
Itr = LVParseTree_CreateIteratorBegin(Tree);
End = LVParseTree_CreateIteratorEnd(Tree);
while (!LVParseTree_Iterator_AreEqual(Itr,End))
{
H_PARSE_TREE_NODE Node = LVParseTree_Iterator_GetNode(Itr);
for (int i = 0; i < LVParseTree_Node_GetLevel(Node); ++i) printf("\t");
if (LVParseTree_Node_IsRule(Node))
printf("$%s:\n",LV_ParseTree_Node_GetRuleName(Node));
if (LVParseTree_Node_IsTag(Node))
printf("{%s}\n",LVParseTree_Node_GetText(Node));
if (LVParseTree_Node_IsTerminal(Node))
printf("\"%s\"\n",LVParseTree_Node_GetText(Node));
LVParseTree_Iterator_Advance(Itr);
}
LVParseTree_Iterator_Release(Itr);
LVParseTree_Iterator_Release(End);
// Note: Node handles don't get released; They are part of the tree,
// and the tree releases them when it gets released
If the grammar was the
top level navigation
example grammar, and the engine recognized "go back", the the above code would print out:
- $directive:
- "go"
- "back"
- {$ = "APPLICATION_BACK"}
See Also