Yin-Yang: Concealing the Deep Embedding of DSLs

Deeply embedded domain-specific languages (EDSLs) intrinsically compromise programmer experience for improved program per-formance. Shallow EDSLs complement them by trading program performance for good programmer experience. We present Yin-Yang, a framework for DSL embedding that uses Scala macros to reli-ably translate shallow EDSL programs to the corresponding deep EDSL programs. The translation allows program prototyping and development in the user friendly shallow embedding, while the cor-responding deep embedding is used where performance is important. The reliability of the translation completely conceals the deep em-bedding from the user. For the DSL author, Yin-Yang automatically generates the deep DSL embeddings from their shallow counterparts by reusing the core translation. This obviates the need for code duplication and leads to reliability by construction