pub trait ConstantResolver {
// Required methods
fn get_real_variable_value(&mut self, var: VariableId) -> Option<f64>;
fn get_int_variable_value(&mut self, var: VariableId) -> Option<i64>;
fn get_str_variable_value(
&mut self,
var: VariableId,
) -> Option<StringLiteral>;
fn get_real_parameter_value(&mut self, param: ParameterId) -> Option<f64>;
fn get_int_parameter_value(&mut self, param: ParameterId) -> Option<i64>;
fn get_str_parameter_value(
&mut self,
param: ParameterId,
) -> Option<StringLiteral>;
}