Extra Utilities for match
1 Pattern Matching in Simple Functions
define/  match*
7.1

Extra Utilities for match

 (require match-plus) package: match-plus

1 Pattern Matching in Simple Functions

syntax

(define/match* (head-id args) body)

 
args = match-expr ...
  | match-expr ... . rest-expr
Allows inline pattern-matching in simple function definitions with behavior similar to match-lambda**. However, only one match clause may be specified since the match patterns are inline with the formals definition. This means an error will be raised if pattern-matching fails, but it is ideal if a function is already contracted in such a way that successful pattern-matching is guaranteed.

Equivalent to:

(define (head-id args*)
  (match* (args*)
    [(args) body]))

where args* is a list of unique identifiers generated corresponding to each arg.

Examples:
> (struct point (x y) #:transparent)
> (define/match* (point-add (point a b) (point c d))
    (point (+ a c) (+ b d)))
> (point-add (point 5 9) (point -3 2))

(point 2 11)