Syntax #

This page describes the native syntax of the Fabric Configuration Language (FCL). Building on the foundation laid by the HashiCorp Configuration Language (HCL), FCL defines a simple, readable, and clear syntax for document templates.

The syntax of FCL has two fundamental components: arguments and blocks. These components constitute the building blocks for crafting configurations within the Fabric Configuration Language.

Arguments #

The arguments are used for assigning values to names within a block. An example of using arguments is as follows:

content text {
  value = "An example of the text value"
}

The argument name, value in the snippet above, can contain letters, digits, underscores (_), and hyphens (-). However, the first character of an identifier must not be a digit.

Blocks #

In the Fabric Configuration Language (FCL), a block serves as a container that defines configurations, data requirements, content structures, variables, and publishing destinations.

For example:

document "test_document" {

  data elasticsearch "events" {
    index = "events"
  }

  content text {
    value = "My custom static text"
  }

  vars {
    foo = "xyz"
  }

}

Each block has a type (for example, document and content) that defines the labels allowed in a block signature. A block can have a name (for example, “events”) or be anonymous, depending on the type of the block and the position of the block in the code. This flexibility contributes to the expressive and modular nature of FCL configurations.

The blocks types can be divided into the following categories based on their purpose:

• Configuration: fabric, config, and meta blocks
• Documents: document block
• Data definitions: data block
• Content definitions: content block
• Content structure: section block
• Publishing / Delivery: publish block
• Referenced blocks / Code reuse: reusing blocks by referencing

Comments #

Fabric language supports three different flavours of comments:

• # begins a single-line comment, ending at the end of the line.
• // is an alternative to # and also defines a single-line comment
• /* and */ are start and end delimiters for a comment that might span over multiple lines.

It’s recommend to use # single-line comment style usually. Future Fabric code formatting tools will prioritise # comments as idiomatic.

Character encoding #

Fabric configuration files must be UTF-8 encoded. Fabric supports non-ASCII characters in comments, and string values.

Next steps #

See Configuration documentation to learn how to configure Fabric and Fabric plugins.