Hitoshi Hasumi
Developer at 株式会社アンドパッド
Matsue, Japan
Summary
👤
Senior🎓
Top SchoolHitoshi Hasumi is a developer with 11 years of engineering experience, currently building software at 株式会社アンドパッド and formerly a decade at Monstar Lab and as a freelance web developer. He is an active open-source maintainer and creator—known for PicoRuby, PRK Firmware, and stewardship of ruby/irb, ruby/reline, and mrubyc—who has contributed significant parser and memory-mapping improvements to the core Ruby repository. Comfortable across web, desktop, mobile, and embedded domains, he blends system architecture skills with hands-on backend and performance work. Based in Matsue, Japan, he favors technical conversations like conference invitations over unsolicited recruiting messages. An MEng graduate with a background in architectural history, he brings a pragmatic, detail-oriented approach that often surfaces in low-level compatibility and memory-allocation refactors.
11 years of coding experience
11 years of employment as a software developer
Master of Engineering (MEng), History of Architecture, Master of Engineering (MEng), History of Architecture at Chiba University
Chinese, イタリア語, スペイン語
Github Skills (18)
memory-management10
c-programming10
c1110
ruby10
c1710
parsing10
text-parsing10
data-structure9
software-design9
posixct9
algorithm9
algorithms9
system-design9
windows9
sys9
Programming languages (12)
Github contributions (5)
ruby/ruby
Nov 2022 - Feb 2025
The Ruby Programming Language
Role in this project:
Back-end Developer & System Architect
Back-end Developer & System ArchitectContributions:23 reviews, 9 PRs, 22 comments in 2 years 3 months
Contributions summary:Hitoshi primarily contributed to the Prism project, a Ruby parser, by addressing platform compatibility and improving the underlying architecture. Their work included adapting the parser to memory-mapped files on different operating systems (POSIX and Windows), which significantly improves performance. They also refactored the memory allocation interface and improved the AST structure, including the decoupling of IMEMO from `rb_ast_t`, enhancing the codebase's flexibility and maintainability. In addition, the user fixed format warnings, demonstrating an attention to code quality and compatibility.
object-orientedruby-languageprogramming-languagerubyc
picoruby/mruby-pico-compiler
Nov 2021 - Mar 2023
Contributions:185 commits, 36 PRs, 140 pushes in 1 year 4 months
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