anchor.diff:                else))
   (import type ())
   (import list (car caddr cadr cdr cddr append for-each map filter
  -              push-cdr! range snoc nth last elem? flat-map))
  +              push-cdr! range snoc nth last elem? flat-map cons))
   (import string (char-at sub))
   (import binders (let*))
   
  
positive.code: 
   You can see the view pattern in use on the last line: we create the view
   with `(matcher \"0x(%d+)\")`, apply it to `x` and then match the
   returned value (`(\"23\")`) against the `?x` pattern."
  
  (import lua/basic (pcall))
  (import lua/math (max))
  
negative.code:          (compile-arm
             (lambda (pt)
               (assert-linearity! (car pt))
               (cond
                 [(eql? '=> (cadr pt))
                  `(,(compile-pattern-test (car pt) val-sym)
                     (let* ,(cons (list 'it val-sym)
                                  (compile-pattern-bindings (car pt) val-sym))
                       ,@(cddr pt)))]
                 [else
                   `(,(compile-pattern-test (car pt) val-sym)
                      (let* ,(compile-pattern-bindings (car pt) val-sym)
                        ,@(cdr pt)))])))]
      `(let* [(,val-sym ,val)]
         (cond ,@(map compile-arm pts)
               [else ,(generate-case-error pts val-sym)]))))
  