DslTutorial.txt

Combining Deep and Shallow embeddings for EDSLs
===============================================

Embedded domain specific languages are typically categorized as either
deep or shallow embeddings. In deep embeddings the object language is
implemented by constructing a syntax tree in the host language. This
syntax tree can then be manipulated and evaluated in many different
ways. Shallow embeddings give a direct interpretation of the object
language in the host language which can can give rise to succinct and
fast implementations.

In this tutorial we will advocate a combined approach, using a deeply
embedded core of the object language and model additional language
features using shallow embeddings. This combination gives considerable
flexibility in experimenting with language features. It also enables a
powerful form of partial evaluation for the object language

This tutorial will include several examples of the synergies that come
out of this combined approach. Some of these examples will be taken
from our experience with implementing Feldspar, a language for digital
signal processing designed together with industrial partners.