private IAstNode Shift(IAstNode left, int level)
{
AstLeaf op = new AstLeaf(_lexer.Read());
IAstNode right = Factor();
Precedence next;
while ((next = NextOperator()) != null && RightFirst(level, next))
{
right = Shift(right, next.Level);
}
return(new ExpressionNode(new Collection <IAstNode>()
{
left, op, right
}));
}
private IAstNode Shift(IAstNode left, int level)
{
AstLeaf op = new AstLeaf(_lexer.Read());
IAstNode right = Factor();
Precedence next;
while ((next = NextOperator()) != null && RightFirst(level, next)) right = Shift(right, next.Level);
return new ExpressionNode(new Collection<IAstNode>() { left, op, right });
}