2020/06/05 by Marie-Anne Lachaux, Lachaux, Marie-Anne, Baptiste Rozière +6 · 4 voices · 81 citations
Computer Science · #Abstract syntax tree #Artificial intelligence #COBOL #Computer science #Correctness #Machine translation #Natural Language Processing Techniques #Natural language processing #Open source #Parsing #Programming language #Python (programming language) #Software #Software Engineering Research #Source code #Topic Modeling #Unit testing #cs.CL #cs.PL
paper · pdf · doi:10.48550/arxiv.2006.03511
published in arXiv (Cornell University) (Cornell University)
openalex publication_date 2020/06/05 · arxiv created 2020/09/22 · arxiv updated 2020/09/23 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
A transcompiler, also known as source-to-source translator, is a system that converts source code from a high-level programming language (such as C++ or Python) to another. Transcompilers are primarily used for interoperability, and to port codebases written in an obsolete or deprecated language (e.g. COBOL, Python 2) to a modern one. They typically rely on handcrafted rewrite rules, applied to the source code abstract syntax tree. Unfortunately, the resulting translations often lack readability, fail to respect the target language conventions, and require manual modifications in order to work properly. The overall translation process is timeconsuming and requires expertise in both the source and target languages, making code-translation projects expensive. Although neural models significantly outperform their rule-based counterparts in the context of natural language translation, their applications to transcompilation have been limited due to the scarcity of parallel data in this domain. In this paper, we propose to leverage recent approaches in unsupervised machine translation to train a fully unsupervised neural transcompiler. We train our model on source code from open source GitHub projects, and show that it can translate functions between C++, Java, and Python with high accuracy. Our method relies exclusively on monolingual source code, requires no expertise in the source or target languages, and can easily be generalized to other programming languages. We also build and release a test set composed of 852 parallel functions, along with unit tests to check the correctness of translations. We show that our model outperforms rule-based commercial baselines by a significant margin.