Dan Lew - Dan Lew Codes

Coding by Magic

Most of my programming ventures begin with a single line of code I’m curious about. Who is calling the code, and how does this code fit into the larger jigsaw puzzle? As a result, “find usages”, “go to declaration”, and “go to implementations” are three of my most often

code design

Programming Priorities

Software development (or, you know, life in general) is all about juggling priorities. For this post, I’m thinking specifically about code design priorities. You only have a limited amount of time to implement a feature, so you have to pick and choose which aspects of it to spend time

politics

Dan's Edina Sample Ballot Election (2024)

As a summary, here's what I'm voting this year on my Edina, MN ballot (along with links to research on why I'm voting that way): * For all partisan races (president, senate, house/state reps) - the DFL candidate. * Statewide constitutional amendment - Yes. * County

politics

Edina City Council (2024)

Another post about local Edina politics, this time the city council race. There are three candidates for two open positions; you get to vote for two: * Ryan Daye * Carolyn Jackson (incumbent) * James Pierce (incumbent) Carolyn Jackson Let’s get the easy one out of the way first. Jackson has been

politics

Edina Mayor Election (2024)

Continuing blogging about Edina local politics… today’s race: mayor! There are two candidates for this race: * Ron Anderson * Jim Hovland (incumbent) Both candidates have tenures in Edina’s government - Anderson served on the Edina city council for one term (he lost his bid for reelection), whereas Hovland has

politics

Hennepin County Commissioner, District 6 Election (2024)

I’m gonna do some more write-ups on local (Edina) elections this year. (Those of you here for software development thoughts: I'll go back to that soon.) Today’s race: Hennepin county commissioner for district 6. There are two candidates for this race: * Heather Edelson (incumbent) * Marissa Simonetti

python

My Evolving Approach to Learning Programming Languages

I’ve recently started a new job that uses Python. The last time I professionally Python’d was 15 years ago, writing backends for mobile apps I worked on. At the time, I was still a novice developer, only a couple years out of college. While I’ve returned to

Software Development is Nonlinear System

Let me tell you a story about when I cut months of work off of a project. Part of Rheaply’s offerings is an inventory management platform. A major problem customers run into is data entry - name & description is not enough, we need colors and manufacturers, dimensions and

Painting “The Death of Socrates” by Jacques-Louis David

javascript

JavaScript Nulls and Programming Minutiae

Socrates once said “the unexamined life is not worth living.” He was immediately sentenced to death afterwards. I, too, often find myself examining the minutiae of programming languages. Thankfully, I have not been put to death for it (yet). After spending more than a decade honing my Android development skills,

music

Playing Trombone Champ... with a Trombone

As a lover of both rhythm games and trombone, of course I got Trombone Champ. Naturally, I wondered: can I control it on an actual trombone?

games

In Search of Exploration Games

(This article is spoiler-free.) In the past few years, I’ve fallen in love with exploration in video games. This mechanic is key in games like Outer Wilds or Subnautica. You’re dropped into the middle of a world and are given free reign to go anywhere, discovering many surprises

android

Sharing code between test modules

In 2015, I wrote a post about sharing code between unit tests and instrumentation tests on Android. Iain Cunningham just pointed out that the method I outlined no longer works. That’s fine for me because I haven’t used that method in years! Nowadays I use modules, which provide

android

Domain-Specific Models

For a long time at Trello Android, we used the same class for parsing API calls (via Gson), making DB transactions (via OrmLite), and displaying data in the UI. Here’s a pseudo-code-y example of a board: @DatabaseTable(tableName = "boards") data class Board( @DatabaseField(columnName = “name”) @SerializedName("

talk

Maintaining Software Correctness

This article is a write-up of a talk I gave at MinneBar 2022. Instead of reading this, you could also watch the recording or view the slides. The title of this talk is "maintaining software correctness." But what exactly do I mean by “correctness”? Let me set the

annual review

Year in Review (2021)

I continue to do less and less each year due to the dual woes of raising a toddler and navigating a pandemic. I also took three months off work this summer and I didn't much feel like doing anything tech then! I suspect that 2022 won't

json

How Trello Android converted from Gson to Moshi

Trello Android recently converted from using Gson [https://github.com/google/gson] to Moshi [https://github.com/square/moshi] for handling JSON. It was a bit tricky so I wanted to document the process. (For context, Trello Android primarily parses JSON. We rarely serialize JSON, and thus most of the

My Programming Earworms

There are tons of articles online that discuss the articles/talks/books that you must consume to become a true programmer [https://en.wikipedia.org/wiki/No_true_Scotsman]. I dislike this framing; it’s gatekeeping, plus software development is such a varied discipline that one person’s essential reading

politics

Edina School Board Election (2021)

Here’s my thinking around this year’s Edina school board elections. The short version is that I’m voting for Erica Allenburg, Dan Arom, Michael Birdman, and Karen Gabler, but read on for more details. -------------------------------------------------------------------------------- The Edina school board [https://www.edinaschools.org/Page/5225] is composed of

kotlin

The dangers of JSON + default values

The following code converts an object to JSON and then back again: val adapter = Moshi.Builder().build().adapter(Foo::class.java) val foo = Foo(bar = null) val json = adapter.toJson(foo) val foo2 = adapter.fromJson(json) check(foo == foo2) I think most of us would expect check() to pass, but

coroutines

Do or do not; there is no tryEmit()

In RxJava, PublishSubject [http://reactivex.io/RxJava/3.x/javadoc/io/reactivex/rxjava3/subjects/PublishSubject.html] (or PublishRelay [https://github.com/JakeWharton/RxRelay] if you’re a cool kid) is a gizmo for manually pumping data into streams like in this contrived example: private val socketSubject = PublishSubject.create<String&

Stop Nitpicking in Code Reviews

One of the best changes I’ve made at work recently is to stop nitpicking in code reviews. Nitpicking isn’t about code that is wrong but suboptimal. It’s pointing out a variable name that could use a more appropriate word, a conditional that could be formatted more cleanly,

rxjava

RxJava vs. Coroutines

At Trello Android, we’ve been considering switching from RxJava to coroutines. We’ve already been using coroutines here and there, but it wasn’t something that we could consider replacing RxJava with until recently because of missing functionality. Now, with the addition of StateFlow and SharedFlow [https://blog.jetbrains.

android

A Warning Regarding Android App Startup with Multiprocess Apps

It’s possible to run different components of your Android application in different processes [https://developer.android.com/guide/components/processes-and-threads#Processes] . I’ve avoided multi-process apps because it’s usually unnecessary and it introduces all sorts of pain, but there are certain use cases that require it. If you’

annual review

Year in Review (2020)

Well. That was quite the year. I didn't do nearly as much this year as in past years for pandemic reasons. I've got a ton of ideas for more blog posts but... finding the will to write them is rough right now. Hopefully things get better

coroutines

Testing Never-Ending Flows

Suppose we’ve got an RxJava test to verify that a stream never emits anything*: @Test fun verifyNeverEmits() { Observable.never<String>().subscribe { fail() } } How would the equivalent one look like for Flow? Suppose I’m testing a theoretical neverFlow(): @Test fun verifyNeverCollects() = runBlocking { neverFlow().collect { fail() } } There’s