Tierless Web Programming in the Large
Gabriel Radanne, Jérôme Vouillon · 2018
Tierless Web programming languages allow combining client-side and server-side programming in a single program. This allows defining expressions with both client and server parts, and at the same time provides good static guarantees regarding client-server communication. However, these nice properties come at a cost: most tierless languages offer very poor support for modularity and separate compilation. To regain this modularity and offer a larger-scale notion of composition, we propose to leverage a well-known tool: ML-style modules. In modern ML languages, the module system is a layer separate from the expression language. Eliom is an extension of OCaml for tierless Web programming which provides type-safe communication and an efficient execution model. In this article, we present how the Eliom module system combines the flexibility of tierless Web programming languages with a powerful module system, thus providing good support for abstraction, modularity and separate compilation. We also show that we can provide all these advantages while providing seamless integration with OCaml and its ecosystem.