Tierless programming languages enable developing the typical server, client and database tiers of a web application as a single mono-linguistic program.
This development style is in stark contrast to the current practice which requires combining multiple technologies and programming languages. A myriad of tierless programming languages has already been proposed, often featuring a JavaScript-like syntax. Instead of introducing yet another, we advocate that it should be possible to develop tierless web applications in existing general-purpose languages. This not only reduces the complexity that developers are exposed to, but also precludes the need for new development tools. We concretize this novel approach to tierless programming by discussing requirements on its future instantiations. We explore the design space of the program analysis for determining and the program transformation for realizing the tier split respectively. The former corresponds to new adaptations of an old familiar, program slicing, for tier splitting. The latter includes several strategies for handling cross-tier function calls and data accesses. Using a prototype instantiation for JavaScript, we demonstrate the feasibility of our approach on an example web application. We conclude with a discussion of open questions and challenges for future research.