static internal DbExpression CompileFunctionView(
string viewDef,
StorageMappingItemCollection mappingItemCollection,
ParserOptions.CompilationMode compilationMode,
IEnumerable <DbParameterReferenceExpression> parameters)
{
Debug.Assert(!String.IsNullOrEmpty(viewDef), "!String.IsNullOrEmpty(viewDef)");
Debug.Assert(mappingItemCollection != null, "mappingItemCollection != null");
Perspective perspective = new TargetPerspective(mappingItemCollection.Workspace);
ParserOptions parserOptions = new ParserOptions();
parserOptions.ParserCompilationMode = compilationMode;
// Parameters have to be accessible in the body as regular scope variables, not as command parameters.
// Hence compile view as lambda with parameters as lambda vars, then invoke the lambda specifying
// command parameters as values of the lambda vars.
DbLambda functionBody = CqlQuery.CompileQueryCommandLambda(
viewDef,
perspective,
parserOptions,
null /* parameters */,
parameters.Select(pInfo => pInfo.ResultType.Variable(pInfo.ParameterName)));
Debug.Assert(functionBody != null, "functionBody != null");
DbExpression expr = functionBody.Invoke(parameters);
return(expr);
}
protected DbFilterExpression ComposeFilter(DbExpression input, DbProjectExpression first, DbFilterExpression second)
{
// source.Project(first).Filter(second) -> source.Filter(e => second(first(e)))
// create lambda expression representing the filter (e => second(e))
DbLambda secondLambda = DbExpressionBuilder.Lambda(second.Predicate, second.Input.Variable);
// invoke lambda with variable from the project
DbFilterExpression composed = first.Input.Filter(secondLambda.Invoke(first.Projection));
return(RebindFilter(input, composed));
}
