My Road to Haskell

Posted in: haskell, life.


My road to Haskell

Recently on Reddit there was a discussion about a job offer posted but that received few attentions, which triggered my interested, being myself very involved in that context. I have also asked if people would have been interested in my “Road to Haskell” (trademark by Chris Forno), and due to the fact, surprisingly, they were, here I am. I wanted to write such a blog post for a while, but never found the inspiration I was looking for. So (long breath), what follows is my story, who I am and how I went from being an Haskell novice to a professional.

Fall 2007

Every great story begins with “Once upon a time” or “Fall YYYY”, so for me we need to rewind time back in 2007. At the time, I was deep into my second year of university, and for the first time I took a look to my curricula’s full program and with my surprise I saw a mandatory course called “Functional Programming”. Before, I never heard about functional programming, being our university quite fundamentalist in Java and OOP. Between general skepticism and mocking from my colleagues, we attended the course (as said, it was mandatory). We were roughly 150 students, but I think probably just 10 or so were really interested. The course used OCaml and unfortunately lacked a bit of real world pragmatism. It was the type of course which really makes you appreciate the succinctness of algebraic data types and recursive functions on data, but alas my colleagues (me include, I’ll be honest) failed to see any real world application with that. In other terms, it was a nice way to program, but in a “toy environment”, or in academia, which is, I guess, one of the false myths we are fighting hard to bust. Anyway, my first foray into functional programming concluded with a full score in that exam, but I rapidly forgot about OCaml and went back into OOP and Java land.

Python-it.org

Fast-forward to Autumn 2009. I graduated with full marks, getting my Bachelor in Computer Science with a thesis regarding a geo-tagging web application, with some flavours of artificial intelligence. It was programmed using my favourite tool at the time, Python. I fell in love with Python during the summer, when my professor suggested it as a nice system language to implement my thesis with (the thesis was on a different topic that I later changed into the aforementioned webapp). I embraced Python completely, being truly refreshing after the clunkiness of Java, so I started blogging about it, and I signed up on Python-it.org, the de-facto forum for Italian pythonists. There I met a lot of nice people, and in general started to expand my horizons, talking and interacting with people outside my university, which developed the “Java tunnel vision” I told you about. I don’t know exactly how happened, but in one topic in that forum they started to talk about functional programming languages, and they named a few: Clojure, Scheme and Haskell. There was a guy I admired a lot which had a crush with Scheme, and being Clojure very similar I started to explore the two languages almost at the same time.

The holy Grail search begins

I bet we all had this phase of our CS life where we relentelessy search for the “Holy Grail” of programming languages, the Satori language if you prefer. The perfect language which will be able to restore our faith into programming. A language which is fast, expressive, with a great library ecosystem, with a strong community. Drunk with the sense of power this search gave me, I really liked to write small programs (typically a Project Euler challenge), and implement/benchmark it using different programming languages. My old blog is full of articles about FP and Clojure (mostly), but this relic is the first piece of Haskell I ever wrote. I wrote it, as usual, to compare implementation and quirks of different functional programming languages. It’s quite funny to get back to this code in retrospective, there were also a lot of grammatical mistakes, and the sentence “the pattern match magic”, makes me smile! Nevertheless, this was my first exposure to the language, and despite missing completely the notion of “monad”, I was able to whip up that program just playing “type tetris” and searching for some basic tutorial on internet. Despite the final goal of the blog post “I’m looking forward to digging deeper in Haskell”, I rapidly went back to Clojure. What didn’t work for me at the time was not the learning curve, but the fact that I couldn’t understand Haskell in its foundations. Reading “Real World Haskell” one of the first topics I was introduced was the “Maybe datatype”, but I wasn’t able to understand why I needed the complication of wrapping my values into something I needed to unwrap later on. “Why not use something like Python’s None of Clojure’s nil?” - I thought at time. So “Real World Haskell” rapidly finished accumulating dust into my bookshelf, so did Haskell in my “to-learn” list.

Searching for the Holy Grail of the Holy Grail

My search didn’t stop to Clojure, though. The thing was that I couldn’t put up with the fact it was running on the JVM, inheriting all its problems. Furthermore, I really wanted something like Common Lisp and its SBCL compiler, capable of producing efficient native code. So, once again, I started searching and I can’t remember why, but in the back on my mind I still had this small thing about Haskell: elegant, capable of compiling to efficient native code, fast if optimized. So I went to my local bookshop and I ordered a copy of “Learn you a Haskell for Great Good!”

Reinassance and rebirth

That book is, hands down, the reason why I am an Haskell programmer today and why I didn’t grow up with the false belief that Haskell sucked and was sour. LYAH really showed me that Haskell was the most elegant programming language I ever saw, built out from mathematical foundations. And suddently I realised why I needed the Maybe type and to wrap my value with it! I was so enthusiastic that I started blogging about it (someone perhaps will remember my “Let’s build and Elemental Battle System in Haskell” series). I was by any means good at it, but I do loved it, and this was the important thing.

My master degree and my thesis

When the time came for me to undertake the ordeal of writing a master degree thesis, I wanted to have the professor which taught us “Distributed Programming”, which is not idiosyncratic against functional programming but certainly appreciate more languages like C++. He despise Java, which creates immediately a strong empathy! I based my thesis project on a simple truth: things like map :: (a -> b) -> [a] -> [b] are parallel by nature, so why we don’t try to implement a nice subset of functional programming functions where the computations can be run on the GPU? I used OpenCL to write a C++ wrapper around them, with sugar on top. My final plan was to bind this C++ framework to a FP language. I do wanted to choose Haskell, but I wasn’t proficient enough at the time, and I didn’t want to get stuck too much trying to make it work. My professor was a bit more accustomed in Erlang, and it offered a sort of “process-based” way to integrate with basically everything, so we choose Erlang. I never programmed in Erlang after my thesis (so no love at first sight!), but I did recognize that C++ was a nice and powerful imperative language, much more widespread than Haskell in Italy, so after graduation my mission was: let’s get proficient with C++ and let’s find a decent job in Italy. Haskell was still there, occupying a small part of my hearth, but I was simply trying to be realistic, maximizing my chances to get a job.

My first job (well, kinda of)

On June, 2012, I started my first job. It was an intership for a company which operates in the defense field. I was really excited, being this place a C++ shop. I said to myself “It’s done! I’m in Rome (my city), doing awesome C++, and if I work my ass hard after the intership I might be offered a full time job, and then I’ll be on the top of the world!”. But life had different projects for me. To start with, the intership was absolutely menial; my job was to investigate whether JavaRT was a suitable candidate to supersed C++ in a system critical environment (short answer: NO). So I basically worked my ass hard and finished the intership in 1 month, despite the 6 they allocated with it. This means that while they tried to feed me with different tasks (which was good), I found myself having a bit of spare time, especially in the morning. It was clear that the job I dreamt about wasn’t exactly the reality I was living in. So in my “idle time”, I used to study Haskell, Okasaki’s book and algorithms and data structures, to keep my mind sharp. It was during my intership I wrote that small Shelly tool for glueing different tools together. During my internship I also explored streaming IO and I asked help to the Haskell community to land a job in functional programming. I always said to myself, for everything in life “For what I lack in [Skill X], I will make it up with perseverance”, which might be read as “Even if you are not Edward Kmett, you should try to get an Haskell job anyway”. So I did.

My path to glory

First thing was to realise what I wanted, so I started by blogging that “I wanted to earn a living with FP”. Ok, so that was out of the way, but how to achieve it? When I asked help the the Haskell community, Doug Beardsley, one of the lead developer of Snap, suggest me to contribute to a large Haskell project to expand my knowledge of the language, and he kindly offered me help to get my foot wet with Snap, in order to be able to contribute to it. I remember with a bittersweet longing those days: I worked 9 to 5, I came back at home, I had a snappy chat with my mom consuming my evening snack and then I was on IRC chatting with Doug about Snaplets, Handlers and other Snap internal concepts. Thanks to him I was able to implement the Snap.Snaplet.Test module which came out in Snap 0.10. It was announced in this changelog and I was damn proud to know that people were going to use something I wrote. It was an awesome sensation (after that, I contributed to dozens of other Haskell libs). But when I read those changelog I was not in my small bedroom in Rome, but in my personal flat in Manchester, because in the meantime I landed a job as Scala Programmer.

The ordeal to my first FP Job

Let’s get back on track on the main plot-line of this story: it’s end of June/July, and I knew for sure that my current job was not what I would have expected, and I wanted to earn a living with FP. As said, I started to study FP seriously and looking for jobs outside Italy, as I knew was impossible to find something FP-related in Rome or even in Italy. So I said “why aim low?” and I applied for Jane Street, which you certainly heard, unless you have been living under a rock. If was end of August, my parents were away for holidays and I had plugged my Mac to my dad’s LCD screen in the living room. I was browsing email with Mutt when I decided to apply for JS (unfortunate acronym, I know). So I prepared a cover letter and I sent it. With my surprise, less then 24 hours later they went back to me: I had a call scheduled with New York city three days later! You could image this was kind of a life changer for me; I was going to have a full blown job interview, for a dream job, completely in a foreign language, and I was scared as fuck! Details are not important here, but I remember myself refreshing OCaml (we meet again!) at 3 o clock in the morning, with sweat pearls dropping from my head, in a really hot Rome’s night. Short story short, with my personal satisfaction I was able to pass 2 phone interviews. I failed the third, and the 11th September (I remember it as it’s an unfortunate date of a tragic event) I received a polite rejection letter. I was sad but at the same time euphoric; I was able, with nothing but my own strength and will, to pass two notoriously-tough job interviews! I still remember the facial expressions of my friends when I told them about my interview questions - “What?” - they said - “binary heaps? Context free grammars?”. The surprise stemmed from the fact rarely in Italy, for entry job positions, you are asked to code. Bad attitude, I know. Anyway, I was happy, I was doing a menial job but inside me I wanted to yell people “I know what a monad is and I passed two phone interviews with Jane Street! And you keep me here writing Word documents!”. I was fully determined, and I applied to different shops until Cake Solutions gave me a chance, even though I had just minor Scala experience, and, in general, no job experience at all. I was scared by the perspective of going in a foreign country, alone, to work with a language I wasn’t fully proficient with! Lots of uncertainties, but I leaped into this new adventure nevertheless! That was, in retrospective, the hardest choice I had to undertake in my life, also complicated by the fact that, when I resigned from the internship, they offered me a full time contract. Basically, my resignations acted as a catalyst for what they had prepared for me. Well, I turned it down. Not for smugness, but just because I was certain that if I wasn’t going to leap into the dark at that time (namely moving to the UK), probably now nothing of this would have never happened. So I went straight and on the 11th of November, 2012, I flew with a single, no return ticket to Manchester.

The Manchester era

Manchester is a particular city; Can’t express myself, but has a nice contract between the old and the new. It’s not uncommon to find very recent building next to second industrial revolution mills. In fact, Cake Solutions’ office is hosted within this mill:

Once arrived I was obviously overwhelmed by the new job, and I asked for suggestions pretty much everywhere and pretty much to everyone (even to Edward Kmett, which I cold-emailed, and he was kind enough to reply. I wrote again to Edward a year later once I got my Haskell job). Scala was a good start but obviously was not the language I wanted to program with, because I wanted to program in Haskell. So again, I spent my gloomy Mancunian evenings hacking some Haskell and developing further my knowledge. It was mainly on personal projects, which sometimes elicited bugs or limitations of existing libraries, which I promptly fixed with PR. This was another important step, as it became natural with time to simply go in, modify a library to fix a bug and yield a PR. Anyway, I was happier in Manchester than I was in Rome (jobwise, I missed the rest), but I knew my journey was not complete. Once in Manchester, I said to myself “wait, now I am in UK, so I can attend one of the Skills Matter courses on Haskell!”, and being Cake Solutions a SM’s partner, I asked if they had access to some sort of discount for these courses, which are notoriously very expensive. I wasn’t even sure if that was worth asking, as I didn’t even have all the money to afford it (my savings were exactly the ones of a guy just started working), but with my immense surprise Cake offered to pay for it in full!. Not just the course, but the train and a one night stay in London! If there is a public space to thank Cake Solutions for this, I think I’ll use this one: thanks! Needless to say, the course was amazing (tiny detail I missed, it’s hosted at the SM’s HQ but Well Typed is responsible for the teaching and the material provided). During those two fantastic days I met another bunch of eager haskellers willing to expand their knowledge, as well as two Well Typed gurus like Edsko de Vries and Andres Loh. Following Andres’ advice I tried to stay in touch after the course, asking Haskell question that Andres, always patiently, answered. Back in Manchester though, everything was the same: I had to put in the cloakroom my Haskell hat, to put back the JVM one. To complicate things, Cake was also moving to a slightly different business plan, where Java and bigger corporate projects were going to be preferred to Scala. How ironic! The fate I tried so hard to escape from came back to haunt me miles away from home! It was early July. It was time for me to change.

Summer 2013

I was lurking in the shadows during my even-gloomier Mancunian evenings for a job post or a pseudo-haskelly job. For a nice coincidence Well Typed was hiring, and I said “I know to not have enough skills to be considered an expert, but I want to accept this challenge and apply anyway. What do I have to lose?”. So I did. I also did a couple of interviews for full time Haskell shops which ultimately yield a failure, but I was happy anyway, because for the first time in my life I was able to start and end a full job interview using nothing but Haskell. This was another important milestone, realizing that Haskell started as an hobby language and now it was a language that, potentially, was as suitable as Python for a job interview. Then I was off for my summer holidays to Italy, with a pending application to WT (which I obviously gave for granted as a failure) and a couple of failed more, but I was confident I was finally proficient enough with the language.

Vieste

I remember it pretty vividly. I was sitting with my girlfriend in a restaurant in Vieste, Puglia, Italy, having a quite eventful dinner. While waiting for our main courses, I lazily checked my email and with my surprise I found a reply to my WT job application of more than 1 month ago from Duncan and Andres! Obviously, being WT so focused in hiring experts I didn’t even pass the pre-screening. Another company could have just said “Ok, you didn’t pass, best luck for your search”. But Well Typed was different! Duncan said that one of WT’s client was looking to hire for a web developer with Haskell and Ruby knowledge. Despite the word “Ruby” made me cringe, I thought to myself “Haskell and web development, I can do this!”. And obviously I said this strong of my contribution to Snap! So I asked Duncan politely to put me in touch with this client. To be honest I wasn’t betting on it too much: previous experiences taught me that usually these things die by natural causes for different reasons: the company stop hiring, they find another candidate before reaching you, the person meant to introduce you simply forgot, etc. Luckily for me, this was not the case. On the 29th of August, when I was back from a long day of consulting in Wales, I received a mail from Duncan with the aforementioned job offer, from the client which would have become my employer, Iris Connect.

(Almost) present days

I took an eventful journey to meet Chris Dornan and the rest of Iris’ team, and spent a Saturday morning with him going through my personal project, a Snap RESTful server really close in terms of business goal to the one Iris is (still) developing. At the end of the day, I had a job offer!

Takehome lessons

So, looking back in retrospective, I was able to go from Haskell novice to professionally employed in less than 2 years, despite I have been tinkering with Haskell from 2010. Was I lucky? smart? stubborn? determined? Probably a bit of everything. This is what I learned and what I think might be an interesting life lesson (sorry for the following, it’s full of conditionals, a nightmare for a non-native writer!):

I hope this wasn’t too long. It probably is, and also full of mistakes. Bear with me, I found myself to be much more comfortable with code! And remember, nothing is free in this life, and come with a price, unless is unconditional love from your parent and certain type of monads:

data F f a = R a | F (f (F f a))

Alfredo

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