In this work, we conduct a study about SPF’s existing string support by running tests on a version of SPF with the latest string support. Base on the results, we then analyze each string method and identify the major challenges in supporting them. We categorize string API functions by type of the challenge, propose several solutions to each of the challenges, and discuss the feasibility and disadvantages of different approaches. We implement support in the case of three string methods according to the proposed solution, leaving other methods as future work.