let · Context variables

Declare variables for the current context and its children, which can be used in templating expressions to create dynamic values.

- _: Say hi
  log: ${greeting}
  let:
    greeting: Bonjour, mes amis !

CAUTION

The esquie and __ identifiers are reserved and cannot be used as a variable name. Attempting to do so will throw an error at runtime.

Variables inheritance

Esquie variables behave similarly to JavaScript scopes, where child contexts inherit values from parent contexts, unless shadowed.

let:
  b: foo
  c: bar
# d:         # ReferenceError
tasks:
  - _: Explaining variables inheritance
    let:
      a: foo # defined
      b: qux # overridden
    # c: bar # inherited
  - _: --------------------------------
    let:
    # a:     # ReferenceError
    # b: foo # inherited
    # c: bar # inherited
      d: boo # defined

About templating order

Since records are templatized depth-first and in declaration order (as explained in the templating rules), you may use variables defined earlier in the same let block.

let:
  a: foo
tasks:
  - _: Showcasing templating order
    let:
      a: ${a}bar    # "foobar"
      b:
        a: ${a}${b} # "foobar"
        b: ${b.a}   # "foobar"

CAUTION

for and let properties (in this order) are exceptions to the general templating order rule, as they are templatized before any other property in the same context.

- log: ${greeting} # "Bonjour, mes amis !"
  let:
    greeting: Bonjour, mes amis !

WARNING

While the let property can itself be templatized, resulting value will not be further templatized (as explained in the templating rules.)

- log: ${foo.bar} # "${true}"
  let:
    foo: "${ { bar: '${true}' } } "