internal void LoadExpression(string data)
{
int length;
if (data == null)
{
length = 0;
_text = new char[length + 1];
}
else
{
length = data.Length;
_text = new char[length + 1];
data.CopyTo(0, _text, 0, length);
}
_text[length] = '\0';
if (_expression != null)
{
// free all nodes
_expression = null;
}
}