Domain-driven design (DDD) provides many techniques and patterns to tame complexities in software applications — even when those are written in functional languages. Unfortunately, there are very limited resources when it comes to implementing DDD in functional languages. …

Couple of months back, I was listening to Eric Evan’s pod cast on Software engineering radio where he mentioned that actor model is a great fit for modeling aggregate root in domain driven design, I was like what, wait? …

Presenting individuals with a diverse range of perspectives can greatly enhance the likelihood of consensus. In our project, we’ve observed that when we provide multiple options to the product owner, the probability of reaching an agreement substantially increases. For instance, in a study involving the presentation of an article with…

Let's look at a function to reserve a book in a library. This function takes a book and returns a BookPlacedOnHold event if reserve is successful. public BookPlacedOnHoldEvent? PlaceOnHold(Book aBook, HoldDuration duration) { if (PatronCanHold(aBook, duration)) { var bookPlacedOnHoldEvent = BookPlacedOnHoldNow(aBook.BookId, aBook.Type, aBook.LibraryBranch, _patron.PatronId, duration); if (_patronHolds.MaximumHoldAfterHolding(aBook)) …

Most compelling reason for data normalisation is to eliminate update anomalies. but, what if updates are not allowed in database, would you still normalize your data ? Let’s say, there is a company, which sells car. Car price has a component called “pickup cost”. This pickup cost has two components…

Take simple Ideas seriously Lot of complex systems have very simple idea behind them. Many scientific breakthrough are just about finding these simple idea in such complex systems. Our understanding increases leaps and bounds if we dwell deep enough in these seemingly simple things. Often we only do this when we struggle with a…

Three mental models In any software, there are at least three mental models at play. First, is the user’s mental model, her understanding of how the software works. Second, Domain expert’s mental model of how Software should work and lastly, developer’s mental model of how the software actually works. …

Developers and management are obsessed with measurement. Important things, many times, are not qualitative. But, when we insist on measuring, We end up measuring unimportant things. For example, companies that don’t understand their customers become feature factories. For them, quantity becomes a proxy to measure value. An extreme example of…

I wanted to add headers to an HTTP request, in Scala. Soon Realised, I can’t create them — instead, I needed to parse them. Once I did that, it returned me headers in a monadic type, which I then needed to unwrap with pattern matching. Oh boy! this was complex…