add simplified notation for attributes in #%top

top.rkt

@@ -11,8 +11,30 @@
 (provide (except-out (all-defined-out) top~)
          (rename-out (top~ #%top)))
 
+;; Allow tag attributes to be specified as follows:
+;; @foo['shape: "square" 'color: "red"]{hello}
 (define-syntax-rule (top~ . id)
-  (λ x `(id ,@x)))
+  (λ x 
+    (define attrs null)
+    (define elements 
+      (let chomp ([x x])
+        (define result+regexp (and ((length x) . >= . 2) 
+                                         (symbol? (car x)) 
+                                         ;; accept strings only
+                                         ;; numbers are difficult because they don't parse as cleanly.
+                                         ;; string will read as a string even if there's no space to the left.
+                                         (or (string? (cadr x))) 
+                                         ;; Looking for symbol ending with a colon
+                                         (regexp-match #rx"^(.*?):(.*)$" (symbol->string (car x)))))
+        (if result+regexp
+            (begin
+               ; reuse result value cadr is first group in match. 
+              (set! attrs (cons (list (string->symbol (cadr result+regexp))(cadr x)) attrs))
+              (chomp (cddr x)))
+            x)))
+    
+    `(id ,@(if (equal? attrs null) null (list (reverse attrs))) ,@elements)))
+
 
 (define-syntax (bound/c stx)
   (syntax-case stx ()