A package to help you easily pretty print structured data ✨

⚙️ This package works with both the Erlang and Javascript target

Installation

To add this package to your Gleam project:

gleam add glam

Pretty printing

When working with structured data (like JSON, XML, lists, ASTs, …) it can be useful to print it in a nice and tidy way. Of course, one could go the quick and dirty way and just string.inspect the data structure and call it a day. However, the result would hardly be readable for complex data structures.

On the other hand, handwriting a pretty printing function can be quite difficult (I sure have spent my fair share of time writing those) and error-prone: there are a lot of moving pieces to juggle and it’s easy for bugs to sneak in.

A pretty printing package like Glam provides some basic building blocks to describe the structure of your data and takes care of the heavy lifting of actually finding the best layout to format the data, gracefully handling line limits and indentation.

Getting started

If you want to get started with Glam, a great starting point is the introductory tutorial which will guide you step by step in writing a pretty printer for lists.

By the end of the tutorial you’ll know most of the package’s API and you’ll have implemented a function that can nicely display lists like this:

pretty_list(["Gleam", "is", "fun!"])
|> doc.to_string(10) // Fit the list on lines of width 10

// [
//   "Gleam",
//   "is",   
//   "fun!",   
// ]

You can also have a look at the examples folder in the GitHub repo, there you’ll also find a JSON pretty printer.

Contributing

If you think there’s any way to improve this package, or if you spot a bug don’t be afraid to open PRs, issues or requests of any kind! Any contribution is welcome 💜