Hi, I'm Noel Welsh. I write software and books, and work on other projects in the software space.

Latest Writing

  • ScalaBridge in 2023
    07 June 2023

    ScalaBridge London is a community for learning Scala, for people who are underrepresented in technology. We last met in 2020, stopping when COVID made it impossible to continue. I want to restart ScalaBridge London. Here's the plan. If you'd like to take part, please signup.

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  • Scala with Cats, Creative Scala, and Scala 3
    17 May 2023

    I'm rewriting my books to include new material and target Scala 3. I'm opening sponsors so you can encourage me to finish faster.

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  • Functional Programming is Based
    06 March 2023

    Function programming is based1; that is, based on principles that allow a systematic and repeatable process for creating software. In this post I'm going illustrate this process with an example of summing the elements of a list, inspired by this conversation. We'll mostly be looking at algebraic data types and structural recursion (which often uses pattern matching, but is not synonymous with it).

    For me, a working functional programmer, this process is one of the main advantages of FP. It means I can spend my mental cycles on understanding the problem, knowing that once I have done so the implementation follows in a straightforward way. The inverse also holds: if someone uses these principles to write code I can easily work out what problem it solves.

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  • A Case Study in Incrementally Improving Code
    09 October 2021

    In this article I'm going to go through the process of improving some code. I'm mentoring a new developer who is applying for their first job. They were asked to complete some tasks on Codility as the first step of the interview process. To get used to the platform they did the first example task, and I advised them on some changes. I'm writing up here the progression from their code to (what I think is) better code. (Since this is the example task, not a task used to assess applicants, I think this is ok to publically post.)

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  • Enough: A Review
    14 March 2021

    "I was three when the elephants ate the house next door," opens a paragraph on page 108 of my copy of Enough, the new book by Dr Cassandra Coburn. It encapsulates a lot of what I like about this book: it deals with important issues but it's also a lot of fun.

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