Microsoft’s Visual Studio Code, the company’s Electron-based source code editor for Linux, macOS and Windows, has been bestowed with the company’s Python Language Server, making it more fluent in the popular programming language.

The Language Server, Microsoft explains, powers the company’s IntelliSense autocomplete system, which not long ago was separated from the company’s Visual Studio IDE so it could be used in other coding tools. It implements Microsoft’s Language Server Protocol which governs how servers and development tools interact for specific programming languages.

IntelliSense is what the Microsoft Office Assistant Clippy (aka Clippit) would have been if natural language parsing were easy and the urge to animate could have been resisted. Because it interacts with a defined domain – programming code – and because Microsoft has put a lot of work into it, IntelliSense manages to provide automated assistance that’s far more relevant than assistive systems focused on social interaction.

Programming languages have to be treated separately by the language server because each has its own quirks. Python for example is a dynamically typed language, which means the data type of variables may change. So inferences that might be used to make suggestions about statically typed code won’t work with Python.

Users of Visual Studio Code have had access to IntelliSense and the Python Extension for a while. The arrival of the Python Language Server should make the code completion experience better and more comprehensive.

“Our Python Language Server uses iterative full-program analysis to track the types of all the variables in your project while simulating execution of all the code in your project,” explains Brett Cannon, Microsoft principal software engineer, in a blog post.

“Normally this kind of approach can take hours for complex programs and require unlimited amounts of RAM, but we have used many tricks to make it complete quickly enough for IntelliSense use.”

With the Python Language Server, developers writing Python code can enjoy seeing syntax errors flagged as they type. They can receive warnings when referenced modules can’t be found. And they can use Typeshed files, which help with type inferencing, to fill in missing completions for modules.

Startup time and import time should be improved too.

The Python Language Server works with .NET Core on Windows, macOS and Linux. It supports Python 2.5 through 3.7, including recent language features like async/await. It is available as an opt-in preview feature in the latest Python Extension for Visual Studio Code, which can be downloaded through the Visual Studio Marketplace or Visual Studio Code’s extension gallery.

To enable it, go to File > Preferences > Settings in Visual Studio Code and add the setting:

"python.jediEnabled": false

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