purplesyringa's blog

Alisa Sireneva

Hi! 👋 I'm Alisa Sireneva (she/her), a software developer and blogger from Moscow. I specialize in performance optimization and systems programming. I also have experience with security, compression, and decentralized systems. My primary goal as a writer is to teach the concepts I regularly apply through accessible content.

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The expression problem and Rust

purplesyringa's blog · 6mo

A few days ago, I stumbled upon a Hacker News discussion about the expression problem – a conundrum that occasionally arises in software design. Some of the commenters noted...

Fenwick layout for interval trees

purplesyringa's blog · 7mo

Fenwick trees and interval trees are well-known data structures in computer science. Interval trees in particular are commonly used in bioinformatics and computational geometry,...

If I hear "design pattern" one more time, I'll go mad

purplesyringa's blog · 7mo

Here, read the intro of the Wikipedia page for Command pattern with me: In object-oriented programming, the command pattern is a behavioral design pattern in which an object is...

"AI discourse" is a joke

purplesyringa's blog · 9mo

In contemporary “AI” discourse, people often make a point that LLM output cannot be trusted, since it contains hallucinations, often doesn’t handle edge cases properly, causes...

Hidden complexity in software development

purplesyringa's blog · 9mo

This is a tech phenomenon that I keep getting blindsided by no matter how much I try to anticipate it. Physical work feels difficult. You can look at someone and realize you...

Splitting independent variables without SSA

purplesyringa's blog · 10mo

I’m making progress on the Java decompiler I’ve mentioned in a previous post, and I want to share the next couple of tricks I’m using to speed it up. Java bytecode is a...

Fast limited-range conversion between ints and floats

purplesyringa's blog · 10mo

This post is about a popular but niche technique I can never find a succinct reference for. I didn’t invent it, I just need a page I can link when giving optimization advice....

Recovering control flow structures without CFGs

purplesyringa's blog · 10mo

I’m working on a Java decompiler because I’m not satisfied with the performance of other solutions. I’ve always heard that decompiling JVM bytecode is a solved problem, but I’ve...

Why performance optimization is hard work

purplesyringa's blog · 11mo

I’m not talking about skill, knowledge, or convincing a world focused on radical acceleration that optimization is necessary. Performance optimization is hard because it’s...

Falsehoods programmers believe about null pointers

purplesyringa's blog · 14mo

Null pointers look simple on the surface, and that’s why they’re so dangerous. As compiler optimizations, intuitive but incorrect simplifications, and platform-specific quirks...

The RAM myth

purplesyringa's blog · 16mo

The RAM myth is a belief that modern computer memory resembles perfect random-access memory. Cache is seen as an optimization for small data: if it fits in L2, it’s going to be...

Thoughts on Rust hashing

purplesyringa's blog · 16mo

In languages like Python, Java, or C++, values are hashed by calling a “hash me” method on them, implemented by the type author. This fixed-hash size is then immediately used by...

Any Python program fits in 24 characters*

purplesyringa's blog · 17mo

If you don’t take whitespace into account. My friend challenged me to find the shortest solution to a certain Leetcode-style problem in Python. They were generous enough to let...

The Rust Trademark Policy is still harmful

purplesyringa's blog · 17mo

Four days ago, the Rust Foundation released a new draft of the Rust Language Trademark Policy. The previous draft caused division within the community several years ago,...

Bringing faster exceptions to Rust

purplesyringa's blog · 17mo

Three months ago, I wrote about why you might want to use panics for error handling. Even though it’s a catchy title, panics are hardly suited for this goal, even if you try to...

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