Select Activity

We have a use case where we need to evaluate a list of components using an iterator, but the result is a list of evaluation results. While the current For activities allow us to iterate over the component list and perform individual evaluations, we have to generate and update the list of evaluation results ourselves in a very cumbersome and error-prone way. A Select activity would be helpful here, one that takes a list of typed objects as input and returns a list of typed objects as output, where the object type can differ between the input and output. This is analogous to SQL Select or LINQ Select.

Input:

Output:

Start by reviewing the existing For activities and the input/output examples in this issue. Compare the requested behavior with SQL Select and LINQ Select, then identify the activity entry points and tests used for iteration. Done means a Select activity accepts a typed list, evaluates each item, and returns a typed list whose element type may differ from the input.

Written by the indexing model from the issue text.