Few months ago, I joined the Haskell Security Response Team. I've been involved in hsec-tools, which aims, in the medium terms, to support the whole s… ...more

A while ago, I was working on some cache-based code, I had a primitive function: fetchCached :: Member (Cached key value) r => key -> Sem r (Boo… ...more

The last thing we have to provide is an OpenAPI description. Thanks to Haskell's type system and servant-openapi3, we can generate it, by first annota… ...more

The last part, in order to make our API is to be able to query it, that's why we have to introduce Views. Since our project is rather simple, we have … ...more

If you followed this series, you may have noticed that, neither in Interface Adapters nor in Drivers. For Interface Adapters, I don't test it because,… ...more

Last time we introduced Interface Adapters with servant to serve a HTTP (REST) API. But we've been left with some Sem r-based definition we have to tr… ...more

After the Use Cases there are the Interface Adapters, namely the HTTP (REST) API. We'll use servant to build a REST API. Let's start by setting the la… ...more

The Use Cases is a simple application-dependant wiring layer, however, I tend to have one or two tests to ensure that Interpreters are well coordinati… ...more

After introducing Commands as our Entites/Core Domain, we then have to introduce next layer: Use Cases. For reference, it is the place where applicati… ...more

Previous log saw the introduction of Commands. One of the reason I favor Clean Architecture specifically over Hexagonal Architecture is to have a pure… ...more

Previous log has let us with the following events: data AbaksEvent = Started {periodId :: PeriodId, name :: Text, from :: Day, to :: Day, initialBal… ...more

I tend to start with the events whenever I start an event source-based system. But first, let's recall the requirements: I should start a Period wit… ...more

A long time ago I "started" a side project called abaks, which is a project for personal bank reconciliation statements. I've been quite bus… ...more

I spend most of my day in a linux terminal (KDE's konsole), doing so, I interact directly with git. I usually starts working on a topic: $ git co -b f… ...more

With Polysemy 1.9.0.0 came the Scoped effect. It's defined as follows: data Scoped (param :: Type) (effect :: Effect) :: Effect where Run :: forall … ...more

With Polysemy 1.9.0.0 came the Opaque effect. It's defined as follows: newtype Opaque (e :: Effect) m a where Opaque :: forall e m a. e m a -> Op… ...more

Until now we only seen "low-level" effects (either classical Monad, or technical effects). On of my main motivation with effects systems is … ...more

When it comes to interpreters relying on other effects, you can either hide or expose them. For example, last year we introduced a Cache effect: data … ...more

At some point you may have strongly typed effects: data DocumentsEffects (d :: Type) (m :: Type -> Type) (a :: Type) where StoreDocument :: d -&g… ...more

As a last lecture, instead of writing regular Plutus code through Haskell, alternatives are presented. First, we have MeshJS, which aims to bootstrap … ...more

In the codebases I have worked on all have multiple global interpreters, most noticeably for production and tests. From time to time, you want to have… ...more

Today's lecture aims to be a wrap-up of previous lectures by implementing a stablecoin. It's supposed to be the indexed (i.e. synchronized) representa… ...more

In a previous log I mentioned that I some point I totally "give up" some of my architecture choices. Let me start by stating that I'm comfor… ...more

We came over Cardano's staking mechanism over and over. At some point, a reward transaction is emitted and, like Script and Minting, there are Validat… ...more

Things have evolved since the beginning of this series! Polysemy had two major releases: 1.8.0.0 and 1.9.0.0. Not a lot of things have evolved, but we… ...more

In my previous log I mentioned the hiring process I set up in my company. In order to hire someone I have to know few things: What's the applicant ba… ...more

While Plutus is the "main" entry-point for smart contracts on Cardano, the only requirement is to produce some Plutus Core, to be run on Car… ...more

As I'll soon change company, I think it's the right time to do a retrospective of these years as CTO, for the first time. (Note that, legally speaking… ...more

I was expecting this lecture for so long: testing. At the time of writing, testing utils are provided in Plutus.Model, as part of plutus-simple-model,… ...more

In our previous log, we ended up with a lot of interpreters: intrepretUserRegistration :: Member InternalUserEffect r => InterpreterFor UserRegistr… ...more

This weeks' lesson is focused on NFT (Non-fungible token), which are "tokens" (non-divisible, duplicable, or copyable). Cardano contains thr… ...more

In our previous log, we have seen that we had to problematics: Splitting effects by concerns Having one target implementation A way to mitigate that… ...more