Three-Shake to Have Two Engineers Speak at Functional Programming Festival
Three-Shake Inc. announced that two of its engineers will speak at the "Functional Programming Matsuri" (FP Matsuri) to be held on July 11-12, 2026, at the Nakano Central Park Conference in Tokyo.
📋 Article Processing Timeline
- 📰 Published: June 2, 2026 at 10:00
- 🔍 Collected: June 2, 2026 at 10:27 (27 min after Published)
- 🤖 AI Analyzed: June 7, 2026 at 00:20 (109h 53m after Collected)
Three-Shake Inc. (Headquarters: Chuo-ku, Tokyo; President & CEO: Takuma Yoshida; hereinafter "Three-Shake") is pleased to announce that two of its engineers will be speaking at the "Functional Programming Matsuri" (FP Matsuri) to be held on Saturday, July 11, and Sunday, July 12, 2026, at the Nakano Central Park Conference.
Functional Programming Matsuri Official Website: https://2026.fp-matsuri.org/
■ About the Functional Programming Matsuri
Last year's "Functional Programming Matsuri" featured a total of 494 participants and 48 speakers in diverse sessions, fostering cross-community exchange and learning. Due to its popularity, we are holding "FP Matsuri 2026" again this year!
Functional programming has been adopted by major languages and frameworks and is now widely practiced. The methodologies themselves continue to evolve. However, there are still voices saying it is "difficult and hard to approach," so it may not be fully widespread yet.
We aim to provide a place where people from various backgrounds can gain new insights through functional programming and interact with each other. Whether you regularly use functional languages, are interested in functional programming, or are simply curious about cutting-edge software development technologies, please join us!
(Quoted from the FP Matsuri official website: https://2026.fp-matsuri.org/)
■ Event Overview
・Date and Time:
Saturday, July 11, 2026, 11:00 AM - 6:30 PM (Doors open at 10:30 AM, Networking event from 7:00 PM)
Sunday, July 12, 2026, 10:00 AM - 6:30 PM (Doors open at 9:30 AM)
・Venue: Nakano Central Park South, 4-10-2 Nakano, Nakano-ku, Tokyo
・Participation Fee: Advance registration is required at the following link:
https://fp-matsuri.doorkeeper.jp/events/196475
■ Speaker Information
@nwiizo, Sreake Division, Three-Shake Inc.
After working as an infrastructure engineer on the development and operation of hosting services, and being woken up many times in the middle of the night for on-call responses, he began to seriously consider the ideal way to handle operations. He is currently a software engineer at Three-Shake Inc. Each time he works on translating technical books such as 'Container Security,' 'Platform Engineering with Kubernetes,' and 'Architecture Modernization,' he finds that for every one thing he learns, three new things he doesn't know appear. He goes by the handle nwiizo online and runs the blog 'Well then, learn at home.'
Saturday, July 11, 14:00 - 14:50
Types are Walls: Don't Fix Bugs in Rust, Make Them Impossible to Express
https://fortee.jp/2026fp-matsuri/proposal/48dabf60-2bcf-47f7-ada0-af638ee6af52
<Session Summary>
"Even without a functional language, you can make bugs impossible to exist using types."
Many systems harbor data where is_paid = true but payment_id is null, or status = "verified" but verified_at doesn't exist. These are not logic bugs; the root cause is that the type system allows expressing "states that should be impossible." The answer this session provides is summed up in one phrase: "Types are walls."
The implementation language will be Rust. Although Rust is not a functional language, it provides tools like algebraic data types (struct/enum), immutability, pattern matching, and ownership. For those unfamiliar with Rust, the language features used will be explained as they appear. The patterns covered are as follows:
Separating types by state: Making UnvalidatedOrder and ValidatedOrder different types so that code using an "unvalidated order for price calculation" is rejected at compile time.
Newtype Pattern: The compiler detects mix-ups between CustomerId and OrderId.
Smart Constructor: Embedding constraints into types instead of comments.
Make Illegal States Unrepresentable: Fundamentally solving the combinatorial explosion of flags and Options using algebraic data types.
Furthermore, in the current era where AI coding agents are commonplace, natural language comments and instructions may be overlooked, but constraints defined by types cannot be physically broken because the code won't compile. Types are not a "request"; they are a "wall."
Masaki Haga (@silasolla), Sreake Division, Three-Shake Inc.
After experience in the development and operation of web applications, he is currently engaged in supporting the modernization of development processes. He widely promotes the adoption of cloud-native technologies, generative AI, and DevOps. In recent years, while involved in development using C# and TypeScript, his favorite language is Standard ML, and he is also interested in technical areas that tend to be black boxes, as well as the underlying theoretical computer science and mathematical logic. At this FP Matsuri, he will participate both as a core staff member handling operations and as a speaker.
<Speaking Time>
Sunday, July 12, 11:30 - 12:20
<Title>
Reading "The Definition of Standard ML" in 2026: As a Source of Modern Robust Software Design
https://fortee.jp/2026fp-matsuri/proposal/5fe03d91-00cc-476f-bfc3-073c6f44aa91
<Session Summary>
Even in the current era where typed languages are widespread, the challenge of invariants and module boundaries depending on implementation persists. Now is the time to return to the source.
"The Definition of Standard ML (Revised)", written about 30 years ago, is a rare document that defines a programming language's specification not in natural language prose but through formal inference rules.
In this presentation, we will interpret this formal specification definition not as mere academic reading, but as a source of practical hints for the challenges modern engineers face daily, such as designing module boundaries and resolving dependencies.
Specifically, we will touch upon four topics relevant to the modern day:
Separation of static semantics (elaboration) and dynamic semantics (evaluation), and dynamic semantics independent of type information.
Generative type abstraction through opaque signatures and type incompatibility defined at the specification level.
Generative functors that preserve type soundness in the presence of mutable references, and module composition that statically completes type dependency resolution.
The design of the value restriction for the coexistence of polymorphism and mutable references, and the trade-off between theory and practice.
Avoiding a barrage of esoteric mathematical formulas, we will explain the intuition through comparisons with code in TypeScript and Rust, along with diagrams.</div>
<section class="news-faq">
<h2>FAQ</h2>
<div class="news-faq-item">
<h3>What is the Functional Programming Matsuri?</h3>
<p>It is a conference for sharing knowledge about functional programming and fostering community exchange.</p>
</div>
<div class="news-faq-item">
<h3>What will Three-Shake engineers present?</h3>
<p>@nwiizo will present on bug elimination using Rust's type system, and Masaki Haga will present on the formal specification of Standard ML.</p>
</div>
<div class="news-faq-item">
<h3>How can I participate?</h3>
<p>Advance registration is required via the Doorkeeper event page. There may be a participation fee.</p>
</div>
</section>
<p class="news-backlink">
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