allow duplicate attrs

quad/quad/atomize.rkt

@@ -6,15 +6,15 @@
 (define/contract (atomize qx)
   ;; normalize a qexpr by reducing it to one-character quads.
   ;; propagate attrs downward by appending to front of attrs list.
-  ;; at then end, duplicates are removed, with frontmost attrs (= added later) given preference
+  ;; ok to have duplicate attrs (leftmost attr takes precedence)
   (qexpr? . -> . (listof qexpr?))
   (let loop ([x qx][attrs null])
     (match x
       [(? string?) (for/list ([c (in-string x)]) ;; strings are exploded
-                             (qexpr attrs (string c)))]
+                     (qexpr attrs (string c)))]
       [(list (? symbol?) (? txexpr-attrs? new-attrs) xs ...) ;; qexprs with attributes are recursed
        (append* (for/list ([x (in-list xs)])
-                          (loop x (append new-attrs attrs))))]
+                  (loop x (append new-attrs attrs))))]
       [(list (? symbol? tag) xs ...) (loop (list* tag null xs) attrs)] ;; qexprs without attributes get null attrs
       [else (raise-argument-error 'atomize "valid item" x)])))
 
@@ -34,9 +34,9 @@
                   (q ((k "v")) "o")
                   (q ((k "v")) "u")))
   (check-equal? (atomize '(q ((k1 "v1")(k2 "42")) "Hi " (q ((k1 "v2")(k3 "foo")) "You")))
-                '((q ((k1 "v1")(k2 "42")) "H")
-                  (q ((k1 "v1")(k2 "42")) "i")
-                  (q ((k1 "v1")(k2 "42")) " ")
-                  (q ((k1 "v2")(k3 "foo")(k2 "42")) "Y")
-                  (q ((k1 "v2")(k3 "foo")(k2 "42")) "o")
-                  (q ((k1 "v2")(k3 "foo")(k2 "42")) "u"))))
+                '((q ((k1 "v1") (k2 "42")) "H")
+                  (q ((k1 "v1") (k2 "42")) "i")
+                  (q ((k1 "v1") (k2 "42")) " ")
+                  (q ((k1 "v2") (k3 "foo") (k1 "v1") (k2 "42")) "Y")
+                  (q ((k1 "v2") (k3 "foo") (k1 "v1") (k2 "42")) "o")
+                  (q ((k1 "v2") (k3 "foo") (k1 "v1") (k2 "42")) "u"))))

quad/quad/qexpr.rkt

@@ -26,14 +26,16 @@
   (check-true (qexpr? '(quad "Hello world")))
   (check-false (qexpr? 'q)))
 
-(define/contract (qexpr attrs . elems)
-  ((txexpr-attrs?) #:rest txexpr-elements? . ->* . qexpr?)
-  (txexpr 'q (remove-duplicates attrs #:key car) elems))
+(define/contract (qexpr #:clean-attrs? [clean-attrs? #f]
+                        attrs . elems)
+  ((txexpr-attrs?) (#:clean-attrs? any/c) #:rest txexpr-elements? . ->* . qexpr?)
+  (txexpr 'q (if clean-attrs? (remove-duplicates attrs #:key car) attrs) elems))
 
 (module+ test
   (check-equal? (qexpr null "foo") '(q "foo"))
   (check-equal? (qexpr '((k "v")) "foo") '(q ((k "v")) "foo"))
-  (check-equal? (qexpr '((k "v2")(k "v1")) "foo") '(q ((k "v2")) "foo")))
+  (check-equal? (qexpr '((k "v2")(k "v1")) "foo") '(q ((k "v2")(k "v1")) "foo"))
+  (check-equal? (qexpr #:clean-attrs? #t '((k "v2")(k "v1")) "foo") '(q ((k "v2")) "foo")))
 
 (define/contract (qml->qexpr x)
   (string? . -> . qexpr?)