  Stan is a popular probabilistic programming language with a self-contained
syntax and semantics that is close to graphical models. Unfortunately, existing
embeddings of Stan in Python use multi-line strings. That approach forces users
to switch between two different language styles, with no support for syntax
highlighting or simple error reporting within the Stan code. This paper tackles
the question of whether Stan could use Python syntax while retaining its
self-contained semantics. The answer is yes, that can be accomplished by
reinterpreting the Python syntax. This paper introduces Yaps, a new frontend to
Stan based on reinterpreted Python. We tested Yaps on over a thousand Stan
models and made it available open-source.
