Discovering and Enjoying Fortran

Background

I have for approximately a year been using Fortran. It is a very interesting computer programming language. It has a very long history, is pleasant to program in, has a fantastic, welcoming, friendly and knowledgeable community.

As a bit of context, I am not a professional developer, but I have worked in ICT areas all my career, doing many different roles. Despite this, for some crazy reason I also like to spend some of my spare time programming. This is mainly due to the creativity and mental challenge it supports and provides, which I really enjoy (yes - my wife thinks I am weird too). Apart from attending school, and a bit of college, I do not have any great academic qualifications, and I have not worked much with the academic establishments either, so I am not too familiar that specific culture.

I have over many years tried lots of different programming languages — but only recently found Fortran. The blame for this is Milan Curcic’s excellent book Modern Fortran which caught my curiosity by accident one day. Ever since reading it, I am intrigued, and keep exploring more of the language and its eco system.

Previously, I mainly enjoyed programming in the Ada language, but until very recently the Ada GNAT compiler was not supported on Apple Silicon (M1) computers natively, so this created an opportunity to look at other alternative languages such as modern Fortran. Unfortunately, Ada support for the latest version of AdaCore’s Community Edition was also dropped for Apple computers, which effectively alienates in many ways the use of Ada as a sensible choice for macOS. So, I was keen to find a language to adopt as a replacement.

When looking into modern Fortran, it became quite clear from all the introductory explanations that is was aimed at scientists, and that its targeted developer is not really general purpose computing, or systems programming. That’s fine, but again I was intrigued as to why a language could have such a specific and specialised audience… time to explore further!

I am certainly not a scientist of any kind, so was a bit concerned that my complete lack of ‘fitting into the advertised point of Fortran’ would soon be an issue:

Fortran is mostly used in domains that adopted computation early–science and engineering. These include numerical weather and ocean prediction, computational fluid dynamics, applied math, statistics, and finance. Fortran is the dominant language of High Performance Computing and is used to benchmark the fastest supercomputers in the world. If you’re writing a program or a library to perform fast arithmetic computation over large numeric arrays, Fortran is the optimal tool for the job.

Oh dear! That is a lot if instant credibility on display. I am certainly not going to be pretending to be able to use Fortran for its stated purpose, so I guess this article and any criticism of Fortran are all my own fault for choosing something that really is not meant for me in the first place… perhaps.

I am (naively?) hoping I have not made a silly mistake, but instead found a hidden gem of a language! Well hidden in plain sight for more than half a century. After all, if it is still being utilised today after approximately 65 years in use, it must have some thing to offer me too.

Curiosity got the better of me, and I told myself I might even learn something from the professionals using it to model the weather, fluid dynamics, tidal changes, medical research, and many other amazing and often unnoticed achievements mankind is involved with day to day, that we all benefit from.

Having the great opportunity to hang out with some of the scientists of the world for some of my spare time was appealing, if not daunting. I just hoped I didn’t get noticed and called out as a charlatan by accidental association:

a person falsely claiming to have a special knowledge or skill.

My apprehension and concerns were supported, as there are lots of interesting (but perhaps not always comprehendible to me!) conversations in the community on scientific areas — which is an insight, and goes to prove I definitely did not miss my calling in life. Although it is forcing me to learn a bit more mathematical cognition (which can’t be a bad thing for anyone), it is not a pre-requisite for participation.

So to be clear, despite the target language use, it is absolutely by no means elitist, exclusive, closed, or judgemental in any way at all. The community is extremely welcoming, open, helpful, supportive, and encouraging. So, while not being a scientist of any kind, that is certainly no reason not to enjoy Fortran or the company of the kind intelligent people you will get to interact with, if you wish.

So, with that context, what do I think of Fortran for a general development language? What would I change? How can I help perhaps?

Observations on Fortran

The purpose of these views is to share my own observations of how I have (perhaps wrongly) understood these Fortran language areas to work. I am obviously using Fortran from a generalist perspective, and many of these issues might be just historical, intentional, or I have not found the right approach yet.

First of all — why use modern Fortran in the first place?

• The language is easy to learn, especially if you have any prior programming experience at all;
• The language is wordy but therefore (to an English speaker at least) should be understandable, if not fully comprehendible;
• The layout of the code is logical and uses common standard programming language terms (ie procedure/function/integer/assignment/etc);
• There are no complex header files and source code files - just single ‘module’ files of code that are used;
• There is a standard library, package manager, good documentation, GitHub code examples, books, videos, training courses, and more;
• There is a choice of different Fortran compilers — both commercial and opensource;
• The language is standardised and therefore clearly defined as a baseline;
• The language is supported well on all major (and many legacy!) platforms such as Windows, Linux, and macOS;
• The language is compiled and has a reputation for being very fast to execute.
• It has active community who are keen to modernise and keep Fortran going, and expand and grow its usage as much as possible too.

Sounds perfect, what are the concerns or areas for improvement?

• It has a lot of history resulting in quite a bit of ‘older’ code less understandable legacy code (ie FORTRAN vs Fortran);
• It is a domain specific language for good reasons — the modernisation work will help open this area up though;
• It is too dependant on other languages and uses them as a ‘crutch’ and for ‘work arounds’ to fill in areas of poorer capability;
• It has lots of duplication of effort historically trying to fix limitations, often done unintentionally in isolation, but for the right reasons;
• The standards that it benefits from may also be hindering (speed wise) its modernisation;
• It needs to keep broadening its usage and grow outside its current solid bastion of use - as an enhancement and expansion - not as a replacement in any way!
• It may have legacy code and a history — but it should be proud of that;
• it is not a real hindrance for ‘Fortran’ to be so mature, and it should not be presented itself as ‘old’ anymore - modernisation is underway after all.

What words would I use to describe modern Fortran?

Mature, friendly, tried and tested, supportive, wise, reliable, dependable, fast, clever, well thought out, clear, unique, modern, understandable.

What are some specifics in more detail?

The following are the areas that bother me the most about Fortran, perhaps just because I don’t get it, or have missed something along the way perhaps.

Pre-processor use:

By default, a lot of the stdlib source see ‘src’ sub directory is stored in the GitHub repo as quite a lot of .fypp processor files. This made me wonder:

• Initially I was very confused by them as a newcomer to Fortran and wondered what they even were, when I was expected just to see .f09 files.
• Once I figured out they were for performing pre-processing, and that another programming language was needed (ie Python), I was a little worried that the language I was interested in developing in, actually needed a whole other language to be able even use it. I didn’t really want to have to use/install/learn/trouble shoot Python just to use Fortran… but I got over it I suppose. I do draw the line at having to install an whole different eco system such as Anaconda. Not because I have any issue with it (I have used it in the past for other reasons) — just that I want to learn and use Fortran, not something else, before I even get going.
• One reason for being interested in Fortran was because it has a modern package manager called fpm. Having used similar for other languages package managers (Ada - alire / OCaml - opam / Rust - cargo / .Net - nuget / etc), I was please to find a the adoption of a modern concept!

Limited Support for connectivity:

One of the first areas I noticed (which of course should not be a surprise given its history) is the lack of easily accessible native support for network connectivity. So, currently using native Fortran it is not possible to request a web page, or Rest API to obtain some JSON data. Fortran can utilise C language code well, so it can get around this by calling other applications and libraries such as curl to perform such tasks. There is work planned to include better support via the Fortran stdlib, but is work in progress currently. For now (like a few other areas), Fortran relies on support from other languages to achieve connections beyond its native language realm.

Highlights of Using Fortran

There have been quite a few notable highlights for me since I started my Fortran adventure, which I thought it would be important to include, as it creates some balance with the negative points made.

Monthly Fortran YouTube Videos: this is a great resource and window into the world of Fortran! Each month, a team of regulars take timeout of the busy lives and meet up virtually for a video call, to discuss key topics relevant to the Fortran community. This resource is a lovely opportunity to hear first hand from many of the key stakeholder, professionals, and core contributor to the many and varied Fortran projects and initiatives. This is not only handy to understand the context behind some of the Discourse discussions, but also put faces to names, and to gain a more in depth understanding of the issues and challenges being faced to ensure the modern Fortran initiative maintains momentum, commitment, and a collaborative focus. Enjoy the recorded monthly videos on YouTube here: Fortran Programming Language or look out for the planned agenda and live call details on the fortran-lang Community Discourse.

Advent of Code in Fortran: I have been slowly working my way through the Advent of Code annual challenges, often using them to try out different languages, and as a way to structure my learning of programming in a fun and purposeful way. Last year (2021) I decided to give Fortran a go, as the language to use to solve the puzzles. It was very enjoyable, and a few of the community also participate as well each year. I certainly learnt a lot about Fortran! It enabled me to consider other approaches to programming, due to the way the Fortran language uses arrays much more, and has very strong features for their manipulation. I did of course get stuck a lot, and have yet to complete every challenge - but that is down to my limitations, not the language!

## What’s Next?

I am certainly going to continue to involve myself with the Fortran language, and the welcoming and helpful community. While I am still exploring other languages too - I am glad I stumbled across Fortran, and look forward to continuing my journey to learn more.

There are exciting times ahead for the language, such as:

• the rapidly evolving LFortran brand new opensource compiler!
• the Fortran Standard Library (stdlib) with its growing list of modern language capabilities;
• the fantastic Fortran web site full of documentation, tutorials, and other background information;
• the constantly improving Fortran Package Manager (FPM) and its many Packages

If you are curious, why not pop in to the Fortran Discourse and see what people are up to, or just hang out there to learn more… it is certainly a exciting time to be involved in the evolution of a great programming language!

Article Details

• Title: Discovering and Enjoying Fortran
• Published Date : 03 Apr 2022