`generate-literals`: treat nonalphabetic identifiers as literals

beautiful-racket-lib/br/private/generate-literals.rkt

@@ -1,17 +1,21 @@
 #lang racket/base
 (require "syntax-flatten.rkt")
-(provide (all-defined-out))
+(provide generate-literals)
+
+(define (literal-identifier? pat-datum)
+  (and (symbol? pat-datum)
+       (not (memq pat-datum '(... _))) ; isn't a reserved identifier
+       (let ([pat-str (symbol->string pat-datum)])
+         (or (not (regexp-match #rx"[A-Z]" pat-str)) ; either doesn't contain at least one uppercase letter ...
+             (not (equal? (string-upcase pat-str) pat-str)))))) ;...  or doesn't contain all uppercase letters
 
 ;; generate literals for any symbols that are not ... or _ and not IN_CAPS
 (define (generate-literals pats)
   (for*/list ([pat-arg (in-list (syntax-flatten pats))]
               [pat-datum (in-value (syntax->datum pat-arg))]
-              #:when (and (symbol? pat-datum)
-                          (not (memq pat-datum '(... _))) ; exempted from literality
-                          (let ([pat-str (symbol->string pat-datum)])
-                            (not (equal? (string-upcase pat-str) pat-str)))))
+              #:when (literal-identifier? pat-datum))
     pat-arg))
 
 (module+ test
   (require rackunit)
-  (check-equal? (map syntax->datum (generate-literals #'(foo 42 BAR _ bar 3bar))) '(foo bar 3bar)))
+  (check-equal? (map syntax->datum (generate-literals #'(foo 42 BAR _ (... ...) bar <=> 3Bar 3bar))) '(foo bar <=> 3Bar 3bar)))