Variables

Defining a variable in Werk is a let-statement. Values are either strings or lists (no numbers). Lists may contain other lists. All strings are valid UTF-8.

Syntax: let identifier = expression. The left-hand side of the = must be a valid identifier (Unicode is supported), and the right-hand side is any expression. All expressions produce a value.

let my-string = "value"

let my-list = ["a", "b", "c"]

All variables are immutable, but variable names may shadow local or global variables with the same name.

let foo = "a"
let foo = "b"   # valid

let bar = foo   # == "b"

Global variables are public

Variables defined at the global scope (i.e., outside of any recipe) are public, and will appear in the output of werk --list. They can be overridden by passing -Dkey=value on the command-line. Comments immediately preceding a global variable will appear in the output as documentation for that variable.

# Set the build profile.
let profile = "debug"

$ werk --list
Global variables:
    profile = "debug" # Set the build profile.

Local variables

Variables defined within a recipe are local to that recipe. Recipes cannot change global variables, but they may shadow global variables in their local scope by defining a variable with the same name as a global variable.