https://blog.rafaelfernandez.dev/tags/software-engineering/ Recent content in Software-Engineering on Home Hugo -- gohugo.io en © 2026 Rafael Fernandez Mon, 23 Mar 2026 00:00:00 +0000 https://blog.rafaelfernandez.dev/posts/how-query-engines-work-1-from-sql-to-results/ Mon, 23 Mar 2026 00:00:00 +0000 https://blog.rafaelfernandez.dev/posts/how-query-engines-work-1-from-sql-to-results/ You write a SQL query, hit enter, and a few milliseconds later results appear. In between, a small compiler has already parsed your text, built a plan, optimized it, and executed it. This post walks through that pipeline with a real query and real Rust code using DataFusion. https://blog.rafaelfernandez.dev/posts/the-elm-architecture-a-loop-that-fits-in-your-head/ Sun, 22 Mar 2026 00:00:00 +0000 https://blog.rafaelfernandez.dev/posts/the-elm-architecture-a-loop-that-fits-in-your-head/ Model, Update, View. Three pieces, one loop, zero surprises. We explain The Elm Architecture from scratch with side-by-side examples in Rust and Scala, trace where the pattern came from, why it keeps showing up in TUIs and functional codebases, and when it stops being the right tool. https://blog.rafaelfernandez.dev/posts/curry-howard-types-as-proofs/ Fri, 20 Mar 2026 00:00:00 +0000 https://blog.rafaelfernandez.dev/posts/curry-howard-types-as-proofs/ Every well-typed program is a proof. Every type is a proposition. This is not a metaphor; it is a mathematical theorem discovered in the 1930s that explains why making invalid states unrepresentable actually works. https://blog.rafaelfernandez.dev/posts/making-invalid-states-unrepresentable-3-real-bugs/ Wed, 18 Mar 2026 00:00:00 +0000 https://blog.rafaelfernandez.dev/posts/making-invalid-states-unrepresentable-3-real-bugs/ Null references, UI loading spinners that show errors and data simultaneously, payments that are captured and voided at the same time. These are not hypotheticals. They are the direct consequence of types that lie about the domain. https://blog.rafaelfernandez.dev/posts/making-invalid-states-unrepresentable-2-algebra-behind-types/ Mon, 16 Mar 2026 00:00:00 +0000 https://blog.rafaelfernandez.dev/posts/making-invalid-states-unrepresentable-2-algebra-behind-types/ Types are called algebraic because they obey arithmetic. Product types multiply, sum types add. Understanding this arithmetic explains why an enum with 5 variants is infinitely more precise than 4 boolean flags. https://blog.rafaelfernandez.dev/posts/making-invalid-states-unrepresentable-1-boolean-flags/ Sat, 14 Mar 2026 00:00:00 +0000 https://blog.rafaelfernandez.dev/posts/making-invalid-states-unrepresentable-1-boolean-flags/ A traffic light that is red and green at the same time. A user who is logged in and logged out simultaneously. Boolean flags make these absurd states perfectly representable, and that is the problem.