/// <summary> Evaluates value for gived qualifier. </summary>
/// <typeparam name="T">Return type</typeparam>
/// <param name="qualifier">Qualifier: osm tag key</param>
/// <param name="converter">Convertrs string to given type</param>
/// <returns>Evaluated value</returns>
public T Evaluate <T>(string qualifier, Func <string, T> converter)
{
Assert();
if (!Declarations.ContainsKey(qualifier))
{
throw new ArgumentException(String.Format(Strings.StyleDeclarationNotFound,
qualifier, _model), qualifier);
}
var declaration = Declarations[qualifier];
return(declaration.IsEval
? declaration.Evaluator.Walk <T>(_model)
: converter(declaration.Value));
}
/// <summary> Evaluates list of values for gived qualifier. </summary>
/// <typeparam name="T">Return type</typeparam>
/// <param name="qualifier">Qualifier: osm tag key</param>
/// <param name="converter">Convertrs string to given type</param>
public IEnumerable <T> EvaluateList <T>(string qualifier, Func <string, T> converter)
{
if (!Declarations.ContainsKey(qualifier))
{
return(Enumerable.Empty <T>());
}
Declaration declaration;
var listDeclaration = Declarations[qualifier] as ListDeclaration;
if (listDeclaration != null)
{
declaration = listDeclaration.Items.First();
return(declaration.Evaluator.Walk <IEnumerable <T> >(_model));
}
declaration = Declarations[qualifier];
return(Evaluate(declaration, converter));
}
/// <summary> Evaluates value for gived qualifier. If not possible, returns default. </summary>
/// <typeparam name="T">Return type</typeparam>
/// <param name="qualifier">Qualifier: osm tag key</param>
/// <param name="default">Default value</param>
/// <returns>Evaluated value</returns>
public T EvaluateDefault <T>(string qualifier, T @default)
{
Assert();
if (!Declarations.ContainsKey(qualifier))
{
return(@default);
}
var declaration = Declarations[qualifier];
if (declaration.IsEval)
{
return(declaration.Evaluator.Walk <T>(_model));
}
return((T)Convert.ChangeType(declaration.Value, typeof(T)));
}
