What is Jsonnet?

Introduction to a domain specific configuration language that helps to define JSON data
30 October 2017   1030

What is Jsonnet?

Jsonnet is a domain specific configuration language that helps you define JSON data. Jsonnet lets you compute fragments of JSON within the structure, bringing the same benefit to structured data that templating languages bring to plain text. The example below illustrates a few features -- referring to another part of the structure, overriding object fields, and string operations.

Use Jsonnet to organize your JSON data, or to help your users organize the data they send to you. It is easy to integrate Jsonnet's library or commandline interpreter into existing systems that take JSON or YAML. Some example situations are application configuration (files in etc), build systems, package definitions, configuration management systems, and cloud deployment agents.

Code examples

// Jsonnet Example
    person1: {
        name: "Alice",
        welcome: "Hello " + self.name + "!",
    person2: self.person1 { name: "Bob" },

Goes to:

   "person1": {
      "name": "Alice",
      "welcome": "Hello Alice!"
   "person2": {
      "name": "Bob",
      "welcome": "Hello Bob!"


If you are interested, visit:

  • Website
  • GitHub
  • Docs

What is Vim.Wasm?

Small introduction to Vim port to WebAssembly with screenshot and developer notes
16 July 2018   69

Vim.wasm is experimental fork of Vim editor to compile it into WebAssembly using emscripten and binaryen.

Developer added some notices:

  • Please access from a desktop browser (Chrome/Firefox/Safari/Edge). Safari seems the best on macOS.
  • Please avoid mobile networks. Your browser will fetch some large files (up to 2.5MB).
  • vim.wasm takes key inputs from DOM keydown event. Please disable your browser extensions which affect key inputs (incognito mode would be the best).
  • This project is very early phase of experiment. Currently only tiny features are supported. More features will be implemented (please see TODO section). And you may notice soon on trying it... it's buggy :)
  • If inputting something does not change anything, please try to click somewhere in the page. Vim may have lost the focus.

The goal of this project is running Vim editor on browser by compiling Vim C sources into WebAssembly. 

Vim.wasm screenshot
Vim.wasm screenshot 

WebAssembly frontend for Vim is implemented as a new GUI frontend. C sources are compiled to each LLVM bitcode files and then they are linked to one bitcode file vim.bc by emccemcc finally compiles the vim.bc into vim.wasm binary using binaryen and generates HTML/JavaScript runtime.

You can find more info at GitHub.