HCL

HCL, aka HashiCorp configuration language, is an open source data notation created in 2014.

Source code:

git clone https://github.com/hashicorp/hcl

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HCL (HashiCorp Configuration Language) is a configuration language built by HashiCorp. The goal of HCL is to build a structured configuration language that is both human and machine friendly for use with command-line tools, but specifically targeted towards DevOps tools, servers, etc. HCL is also fully JSON compatible. That is, JSON can be used as completely valid input to a system expecting HCL. This helps makes systems interoperable with other systems. HCL is heavily inspired by libucl, nginx configuration, and others similar.

HCL is developed on GitHub and has 4,132 stars
HCL docs
There are at least 180,390 HCL repos on GitHub
HCL first developed in HashiCorp
file extensions for HCL include hcl, nomad, tf, tfvars and workflow
The Google BigQuery Public Dataset GitHub snapshot shows 2k users using HCL in 3k repos on GitHub
Monaco package for syntax highlighting HCL
GitHub supports syntax highlighting for HCL

Example from the web:

variable "ami" {
   description = "the AMI to use"
}
<<FOO
hello
world
FOO

Example from Riju:

output = "Hello, world!"

Example from Linguist:

consul = "1.2.3.4"

// This is a comment
template "foo" {
  bar = "zip"
}

HCL Keywords

var local path for_each any string number bool true false null if else endif for in endfor

Feature	Supported	Token	Example
Conditionals	✓
Booleans	✓	true false
MultiLine Comments	✓	/* */	/* A comment */
Strings	✓
Comments	✓		// A comment
Line Comments	✓	//	// A comment
Semantic Indentation	X

HCL - Data notation

Language features