From 9bfc19e8f1591fff4b2b17231d48d211eb33e599 Mon Sep 17 00:00:00 2001
From: Matthew Butterick <mb@mbtype.com>
Date: Sat, 6 Sep 2014 07:42:08 -0700
Subject: [PATCH] add make-default-tag-function

---
 tag.rkt | 17 +++++++++++++----
 top.rkt |  2 +-
 2 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/tag.rkt b/tag.rkt
index 4f3b834..17f9e6d 100644
--- a/tag.rkt
+++ b/tag.rkt
@@ -1,8 +1,8 @@
 #lang racket/base
+(require txexpr sugar/define) 
 
-(provide make-tag-function)
-
-(define (make-tag-function . ids)
+(define/contract+provide (make-default-tag-function . ids)
+  (() #:rest (listof txexpr-tag?) . ->* . procedure?)
   (define (make-one-tag id)
     (λ x 
       (define reversed-pieces ; list of attribute pairs, and last element holds a list of everything else, then reversed
@@ -26,4 +26,13 @@
       
       `(,id ,@(if (equal? attrs null) null (list (reverse attrs))) ,@body)))
   
-  (apply compose1 (map make-one-tag ids)))
\ No newline at end of file
+  (apply compose1 (map make-one-tag ids)))
+
+
+
+(define/contract+provide (split-attributes parts)
+  (list? . -> . (values txexpr-attrs? txexpr-elements?))
+   (define dummy-tag (gensym))
+   (define dummy-txexpr (apply (make-default-tag-function dummy-tag) parts))
+   (define-values (tag attrs elements) (txexpr->values dummy-txexpr))
+   (values attrs elements))
\ No newline at end of file
diff --git a/top.rkt b/top.rkt
index ac8a4ad..800c628 100644
--- a/top.rkt
+++ b/top.rkt
@@ -13,7 +13,7 @@
 
 (define-syntax (top~ stx)
   (syntax-case stx ()
-    [(_ . id) #'(make-tag-function 'id)]))
+    [(_ . id) #'(make-default-tag-function 'id)]))
 
 (define-syntax (def/c stx)
   (syntax-case stx ()