rec

rec is Coalton’s named-recursion form, similar to Scheme’s “named-let”.

Syntax

(rec ⟨name-spec⟩ ((⟨var⟩ ⟨init⟩) ...)
  ⟨body⟩)

;; ⟨name-spec⟩ := ⟨name⟩
;;              | (⟨name⟩ ⟨type⟩)

Semantics

• rec is useful for iteration. ⟨name⟩ should name a function to be called tail recursively.
• The recursive name can optionally carry an explicit type.
• The names go or % are often used.
• Tail recursion is not enforced.
• ⟨body⟩ has an implicit progn.

Example

(rec % ((i n) (acc 0))
  (if (== i 0)
      acc
      (% (1- i) (+ acc i))))