Polyglot programming allows developers to choose the right language to solve tough engineering problems

Programming languages can divide opinion. They are, for many engineers, a mark of identity. Yes, they say something about the kind of work you do, but they also say something about who you are and what you value. But this is changing, with polyglot programming becoming a powerful and important trend.

We’re moving towards a world in which developers are no longer as loyal to their chosen programming languages as they were. Instead, they are more flexible and open minded about the languages they use.

This year’s Skill Up report highlights that there are a number of different drivers behind the programming languages developers use which, in turn, imply a level of contextual decision making. Put simply, developers today are less likely to stick with a specific programming language, and instead move between them depending on the problems they are trying to solve and the tasks they need to accomplish.

Download this year's Skill Up report here.

[caption id="attachment_28338" align="aligncenter" width="554"] Skill Up 2019 data[/caption]

As the data above shows, languages aren’t often determined by organizational requirements. They are more likely to be if you’re primarily using Java or C#, but that makes sense as these are languages that have long been associated with proprietary software organizations (Oracle and Microsoft respectively); in fact, programming languages are often chosen due to projects and use cases.

The return to programming language standardization

This is something backed up by the most recent ThoughtWorks Radar, published in April. Polyglot programming finally moved its way into the Adopt ‘quadrant’. This is after 9 years of living in the Trial quadrant. Part of the reason for this, ThoughtWorks explains, is that the organization is seeing a reaction against this flexibility, writing that “we're seeing a new push to standardize language stacks by both developers and enterprises.”

The organization argues - quite rightly - that , “promoting a few languages that support different ecosystems or language features is important for both enterprises to accelerate processes and go live more quickly and developers to have the right tools to solve the problem at hand.”

Arguably, we’re in the midst of a conflict within software engineering. On the one hand the drive to standardize tooling in the face of increasingly complex distributed systems makes sense, but it’s one that we should resist. This level of standardization will ultimately remove decision making power from engineers.

What’s driving polyglot programming?

It’s probably worth digging a little deeper into why developers are starting to be more flexible about the languages they use. One of the most important drivers of this change is the dominance of Agile as a software engineering methodology. As Agile has become embedded in the software industry, software engineers have found themselves working across the stack rather than specializing in a specific part of it.

Full-stack development and polyglot programming

This is something suggested by Stack Overflow survey data. This year 51.9% of developers described themselves as full-stack developers compared to 50.0% describing themselves as backend developers. This is a big change from 2018 where 57.9% described themselves as backend developers compared to 48.2% of respondents calling themselves full-stack developers.

Given earlier Stack Overflow data from 2016 indicates that full-stack developers are comfortable using more languages and frameworks than other roles, it’s understandable that today we’re seeing developers take more ownership and control over the languages (and, indeed, other tools) they use.

With developers sitting in small Agile teams working more closely to problem domains than they may have been a decade ago, the power is now much more in their hands to select and use the programming languages and tools that are most appropriate.

If infrastructure is code, more people are writing code... which means more people are using programming languages

But it's not just about full-stack development. With infrastructure today being treated as code, it makes sense that those responsible for managing and configuring it - sysadmins, SREs, systems engineers - need to use programming languages.

This is a dramatic shift in how we think about system administration and infrastructure management; programming languages are important to a whole new group of people.

Python and polyglot programming

The popularity of Python is symptomatic of this industry-wide change. Not only is it a language primarily selected due to use case (as the data above shows), it’s also a language that’s popular across the industry.

When we asked our survey respondents what language they want to learn next, Python came out on top regardless of their primary programming language.

[caption id="attachment_28340" align="aligncenter" width="563"] Skill Up 2019 data[/caption]

This highlights that Python has appeal across the industry. It doesn’t fit neatly into a specific job role, it isn’t designed for a specific task. It’s flexible - as developers today need to be.

Although it’s true that Python’s popularity is being driven by machine learning, it would be wrong to see this as the sole driver. It is, in fact, its wide range of use cases ranging from scripting to building web services and APIs that is making Python so popular.

Indeed, it’s worth noting that Python is viewed as a tool as much as it is a programming language. When we specifically asked survey respondents what tools they wanted to learn, Python came up again, suggesting it occupies a category unlike every other programming language.

[caption id="attachment_28341" align="aligncenter" width="585"] Skill Up 2019 data[/caption]

What about other programming languages?

The popularity of Python is a perfect starting point for today’s polyglot programmer. It’s relatively easy to learn, and it can be used for a range of different tasks. But if we’re to convincingly talk about a new age of programming, where developers are comfortable using multiple programming languages, we have to look beyond the popularity of Python at other programming languages.

Perhaps a good way to do this is to look at the languages developers primarily using Python want to learn next. If you look at the graphic above, there’s no clear winner for Python developers. While every other language is showing significant interest in Python, Python developers are looking at a range of different languages.

This alone isn’t evidence of the popularity of polyglot programming, but it does indicate some level of fragmentation in the programming language ‘marketplace’. Or, to put it another way, we’re moving to a place where it becomes much more difficult to say that given languages are definitive in a specific field.

The popularity of Golang

Go has particular appeal for Python programmers with almost 20% saying they want to learn it next. This isn’t that surprising - Go is a flexible language that has many applications, from microservices to machine learning, but most importantly can give you incredible performance. With powerful concurrency, goroutines, and garbage collection, it has features designed to ensure application efficiency.

Given it was designed by Google this isn’t that surprising - it’s almost purpose built for software engineering today. It’s popularity with JavaScript developers further confirms that it holds significant developer mindshare, particularly among those in positions where projects and use cases demand flexibility.

Read next: Is Golang truly community driven and does it really matter?

A return to C++

An interesting contrast to the popularity of Go is the relative popularity of C++ in our Skill Up results. C++ is ancient in comparison to Golang, but it nevertheless seems to occupy a similar level of developer mindshare. The reasons are probably similar - it’s another language that can give you incredible power and performance.

For Python developers part of the attraction is down to its usefulness for deep learning (TensorFlow is written in C++). But more than that, C++ is also an important foundational language. While it isn’t easy to learn, it does help you to understand some of the fundamentals of software. From this perspective, it provides a useful starting point to go on and learn other languages; it’s a vital piece that can unlock the puzzle of polyglot programming.

A more mature JavaScript

JavaScript also came up in our Skill Up survey results. Indeed, Python developers are keen on the language, which tells us something about the types of tasks Python developers are doing as well as the way JavaScript has matured. On the one hand, Python developers are starting to see the value of web-based technologies, while on the other JavaScript is also expanding in scope to become much more than just a front end programming language.

Read next: Is web development dying?

Kotlin and TypeScript

The appearance of other smaller languages in our survey results emphasises the way in which the language ecosystem is fragmenting. TypeScript, for example, may not ever supplant JavaScript, but it could become an important addition to a developer’s skill set if they begin running into problems scaling JavaScript.

Kotlin represents something similar for Java developers - indeed, it could even eventually out pace its older relative. But again, it’s popularity will emerge according to specific use cases. It will begin to take hold in particular where Java’s limitations become more exposed, such as in modern app development.

Rust: a goldilocks programming language perfect for polyglot programming

One final mention deserves to go to Rust. In many ways Rust’s popularity is related to the continued relevance of C++, but it offers some improvements - essentially, it’s easier to leverage Rust, while using C++ to its full potential requires experience and skill.

Read next: How Deliveroo migrated from Ruby to Rust without breaking production

One commenter on Hacker News described it as a ‘Goldilocks’ language - “It's not so alien as to make it inaccessible, while being alien enough that you'll learn something from it.”

This is arguably what a programming language should be like in a world where polyglot programming rules. It shouldn’t be so complex as to consume your time and energy, but it should also be sophisticated enough to allow you to solve difficult engineering problems.

Learning new programming languages makes it easier to solve engineering problems

The value of learning multiple programming languages is indisputable. Python is the language that’s changing the game, becoming a vital additional extra to a range of developers from different backgrounds, but there are plenty of other languages that could prove useful.

What’s ultimately important is to explore the options that are available and to start using a language that’s right for you. Indeed, that’s not always immediately obvious - but don’t let that put you off. Give yourself some time to explore new languages and find the one that’s going to work for you.