Use `match-define`

codegen/runtime.rkt

@@ -20,14 +20,13 @@
 ;; function value for the error handler up front.  We want to delay that decision
 ;; till parse time.
 (define (the-error-handler tok-ok? tok-name tok-value start-pos end-pos)
-  (match (positions->srcloc start-pos end-pos)
-    [(list src line col offset span)
+  (match-define (list src line col offset span) (positions->srcloc start-pos end-pos))
   ((current-parser-error-handler) tok-name 
                                   tok-value
                                   offset
                                   line
                                   col 
-                                     span)]))
+                                  span))
 
 
 

rules/parser.rkt

@@ -165,15 +165,15 @@
                 [(string=? $2 "?") (cons 0 1)]
                 [(regexp-match #px"^\\{(\\d+)?(,)?(\\d+)?\\}$" $2) ; "{min,max}" with both min & max optional
                  => (λ (m)
-                      (match m
-                        [(list all min range? max) (let* ([min (if min (string->number min) 0)]
+                      (match-define (list all min range? max) m)
+                      (let* ([min (if min (string->number min) 0)]
                              [max (cond
                                     [(and range? max) (string->number max)]
                                     [(not (or range? max)) (if (zero? min)
                                                                #f ; {} -> {0,}
                                                                min)] ; {3} -> {3,3}
                                     [else #f])])
-                                                     (cons min max))]))]
+                        (cons min max)))]
                 [else (raise-argument-error 'grammar-parse "unknown repetition operator" $2)]))
         (pattern-repeat (position->pos $1-start-pos)
                         (position->pos $2-end-pos)