/// <summary>
/// The entry-point of <see cref="PageSelectVisitor"/>.
/// </summary>
public static IEnumerable <PropQueryParameters> Process <TSource, TResult>(
Expression <Func <TSource, TResult> > expression, out Func <PageData, TResult> processedExpression)
{
var visitor = new PageSelectVisitor(expression.Parameters.Single());
var body = visitor.Visit(expression.Body);
var gatherer = new UsedPropertiesGatherer();
gatherer.Gather(body, visitor.m_pageDataGetInfoCall);
var parameters = visitor.m_parameters;
if (!gatherer.UsedDirectly && gatherer.UsedProperties.Any(p => !NonInfoProperties.Contains(p)))
{
var propQueryParameters = new PropQueryParameters("info").WithProperties(gatherer.UsedProperties);
var tokens = gatherer.UsedProperties
.Where(p => p.EndsWith("token"))
.Select(p => p.Substring(0, p.Length - "token".Length))
.ToArray();
if (tokens.Any())
{
propQueryParameters = propQueryParameters.AddSingleValue("token", tokens.ToQueryString());
}
parameters["info"] = propQueryParameters;
}
processedExpression =
Expression.Lambda <Func <PageData, TResult> >(body, visitor.m_pageDataParameter).Compile();
return(parameters.Values);
}
/// <summary>
/// Parses a <c>select</c> expression.
/// </summary>
/// <param name="expression">Expression to parse.</param>
/// <param name="previousParameters">Previous parameters, whose values should be included in the result.</param>
public static QueryParameters <TSource, TResult> ParseSelect <TSource, TResult>(
Expression <Func <TSource, TResult> > expression, QueryParameters <TSource, TSource> previousParameters)
{
var parameter = expression.Parameters.Single();
var gatherer = new UsedPropertiesGatherer();
gatherer.Gather(expression.Body, parameter);
var usedProperties = gatherer.UsedDirectly ? null : gatherer.UsedProperties.Select(p => p.ToLowerInvariant());
return(previousParameters.WithSelect(usedProperties, expression.Compile()));
}
