The polymorphic RPC calculus allows programmers to write succinct multitier programs using polymorphic location constructs. However, until now it lacked an implementation. We develop an experimental programming language based on the polymorphic RPC calculus. We introduce a polymorphic Client-Server (CS) calculus with the client and server parts separated. In contrast to existing untyped CS calculi, our calculus is not only able to resolve polymorphic locations statically, but it is also able to do so dynamically. We design a type-based slicing compilation of the polymorphic RPC calculus into this CS calculus, proving type and semantic correctness. We propose a method to erase types unnecessary for execution but retaining locations at runtime by translating the polymorphic CS calculus into an untyped CS calculus, proving semantic correctness.

Embedded domain specific languages (EDSLs) are used to represent special-purpose code in a general-purpose language and they are used for applications like vector calculations and run-time code generation. Often, code in an EDSL is compiled to a target (e.g. GPU languages, JVM bytecode, assembly, JavaScript) and needs to interface with other code that is available at that level but uses other data representations or calling conventions. We present an approach for safely making available such APIs in a typed EDSL, guaranteeing correct conversions between data representations and the respect for calling conventions. When the code being interfaced with is the result of static compilation of host language code, we propose a way to auto-generate the needed boilerplate using meta-programming. We instantiate our technique with JavaScript as the target language, JS-Scala as the EDSL, Scala.js as the static compiler and Scala macros to generate the boilerplate, but our design is more generally applicable. We provide evidence of usefulness of our approach through a prototype implementation that we have applied in a non-trivial code base.