DSL-R1: From SQL to DSL for Training Retrieval Agents across Structured and Unstructured Data with Reinforcement Learning. - Yunhai Hu; Junwei Zhou; Yumo Cao; Yitao Long; Yiwei Xu; Qiyi Jiang; Weiyao Wang 006; Xiaoyu Cao; Zhen Sun; Yiran Zou; Nan Du (CoRR, 2026)