compile/define-global-values

Symbol: compile/define-global-values

define-global-values is the special that global var over a pattern lowers to.

Syntax: (define-global-values PATTERN VALUE) or (define-global-values PATTERN)

Same PATTERN shapes as compile/define-values: a list of names, nested lists, and one *: rest collector; with a VALUE, a single name as well. Without VALUE the names are bound at the module and nothing is stored; a single name without a value is compile/define-global.

Use-case: Bind several module names at once from inside any scope. Where compile/define-values declares its names in the scope the form appears in, this form binds them at the module, as compile/define-global does for one name.

Behaviour: Records every name the pattern binds as a module binding for the current scope, compiles VALUE, then unpacks it into those names. A name the same scope already declared with var cannot also be bound here; the compiler raises CompilerError. The form’s value is None.

Examples:

(define-global-values [lo hi] (values 1 9))

(define [setup]
  (define-global-values [first *: rest] (range 5))
  None)
(setup)
rest    ;; (1, 2, 3, 4)