Abstract:
Programmers design, write, and understand programs with
a high-level structure in mind. Existing programming languages are
not very good at capturing this structure because they must
include low-level implementation details. To address this problem
we introduce Twig, a programming language that allows for
domain-specific logic to be encoded alongside low-level
functionality. Twig's language is based on a simple, formal
calculus that is amenable to both human and machine reasoning.
Users may introduce rules that rewrite expressions, allowing for
user-defined optimizations. Twig can also incorporate procedures
written in a variety of low-level languages. Our implementation
supports C and Python, but our abstract model can accommodate other
languages as well. We present Twig's design and formal semantics
and discuss our implementation. We demonstrate Twig's use in two
different domains, multi-language programming and GPU
programming, and compare Twig against a well-known typemapping
system, SWIG.
