public static ExpressionNode ResolveOperatorExpression <TSymbol>(IParseTree <TSymbol> parseTree, int opLevel) where TSymbol : ISymbol <TSymbol>
{
if (opLevel > OP_BOTTOM_LEVEL)
{
// these part proceeds op from level 15 to 5
bool isLeft = ASTBuilder.IsLeftOperator(parseTree.Symbol);
// get childrens connected by operators (one level lower)
var childs = isLeft ?
ASTBuilder.Children(parseTree).Reverse().GetEnumerator() : // if left-to-right then reverse arguments
ASTBuilder.Children(parseTree).GetEnumerator();
Debug.Assert(childs.MoveNext()); // set enumerator to the first element (must be present)
return(ParseBinOperator(childs, opLevel - 1, isLeft));
}
else
{
// continue parsing lower level expressions
Debug.Assert(opLevel == OP_BOTTOM_LEVEL); // op level must be 4
var node = ASTBuilder.FirstChild(parseTree); // Operator4Expression -> Operator3Expression
// Operator3Expression -> (prefix_operator)* Operator2Expression
var childs = ASTBuilder.Children(node).Reverse().GetEnumerator();
Debug.Assert(childs.MoveNext());
var op2 = childs.Current; // last child -> Operator2Expression
var op2Childs = ASTBuilder.RevChildrenEnumerator(op2);
Debug.Assert(op2Childs.MoveNext());
return(AddPrefixOperators(3, ParseOperator2(op2Childs), childs));
}
}