[Onward!'25] What You See Is What It Does: A Structural Pattern for Legible Software

What You See Is What It Does: A Structural Pattern for Legible Software (Video, Onward! 2025)
Eagon Meng and Daniel Jackson
(Massachusetts Institute of Technology, USA; Massachusetts Institute of Technology, USA)

Abstract: The opportunities offered by LLM coders (and their current limitations) demand a reevaluation of how software is structured. Software today is often “illegible”—lacking a direct correspondence between code and observed behavior—and insufficiently modular, leading to a failure of three key requirements of robust coding: incrementality (the ability to deliver small increments by making localized changes), integrity (avoiding breaking prior increments) and transparency (making clear what has changed at build time, and what actions have happened at runtime). A new structural pattern offers improved legibility and modularity. Its elements are concepts and synchronizations: fully independent services and event-based rules that mediate between them. A domain-specific language for synchronizations allows behavioral features to be expressed in a granular and declarative way (and thus readily generated by an LLM). A case study of the RealWorld benchmark is used to illustrate and evaluate the approach.

Article: https://doi.org/10.1145/3759429.3762628

ORCID: https://orcid.org/0009-0004-0855-1584, https://orcid.org/0000-0003-4864-078X

Video Tags: Programming, software engineering, large language models, artificial intelligence, modularity, concept design, mediators, onward25papers-p24-p, doi:10.1145/3759429.3762628, orcid:0009-0004-0855-1584, orcid:0000-0003-4864-078X

Presentation at the Onward! 2025 conference, October 12–18, 2025, https://2025.splashcon.org/track/spla...
Sponsored by ACM SIGPLAN, ACM SIGAda,