public CLS_Content.Value ComputeValue(CLS_Content content)
{
content.InStack(this);
CLS_Content.Value left = content.Get(value_name);
ICLS_Type type = content.environment.GetType(left.type);
CLType returntype;
left.value = type.Math2Value(content, mathop, left.value, CLS_Content.Value.One, out returntype);
//left.value = type.ConvertTo(content, left.value, v.type);
//content.Set(value_name, left.value);
content.OutStack(this);
return content.Get(value_name);
}