Existing Programming-By-Example (PBE) systems often rely on simplified benchmarks that fail to capture the high structural complexity-such as deeper nesting and frequent Unions-of real-world regexes. To overcome the resulting performance drop, we propose ReSyn, a synthesizer-agnostic divide-and-conquer framework that decomposes complex synthesis problems into manageable sub-problems. We also introduce Set2Regex, a parameter-efficient synthesizer capturing the permutation invariance of examples. Experimental results demonstrate that ReSyn significantly boosts accuracy across various synthesizers, and its combination with Set2Regex establishes a new state-of-the-art on challenging real-world benchmark.
@article{arxiv.2603.24624,
title = {ReSyn: A Generalized Recursive Regular Expression Synthesis Framework},
author = {Seongmin Kim and Hyunjoon Cheon and Su-Hyeon Kim and Yo-Sub Han and Sang-Ki Ko},
journal= {arXiv preprint arXiv:2603.24624},
year = {2026}
}