improvements to ->html

scribblings/template.scrbl

@@ -28,7 +28,7 @@ Convert @racket[_xexpr] to an HTML string. Similar to @racket[xexpr->string], bu
 (->html tx)
 ]
 
-The optional keyword arguments @racket[_html-tag] and @racket[_html-attrs] let you replace the tag and attributes in the generated HTML.
+The optional keyword arguments @racket[_html-tag] and @racket[_html-attrs] let you set the outer tag and attributes for the generated HTML. If @racket[_xexpr] already has an outer tag or attributes, they will be replaced.
 
 @examples[#:eval my-eval
 (define tx '(root ((id "huff")) "Bunk beds"))
@@ -38,12 +38,29 @@ The optional keyword arguments @racket[_html-tag] and @racket[_html-attrs] let y
 (->html tx #:tag 'div #:attrs '((id "doback")))
 ]
 
-The @racket[_splice-html?] option will strip the outer tag from the generated HTML.
+Whereas if @racket[_xexpr] has no tag or attributes, they will be added. If you supply attributes without a tag, you'll get an error.
 
 @examples[#:eval my-eval
-(define tx '(root (p "Orange marmalade")))
+(define x "Drum kit")
+(->html x)
+(->html x #:tag 'div)
+(->html x #:tag 'div #:attrs '((id "doback")))
+(->html x #:attrs '((id "doback")))
+]
+
+
+If the generated HTML has an outer tag, the @racket[_splice-html?] option will strip it off. Otherwise this option has no effect.
+
+@examples[#:eval my-eval
+(define tx '(root (p "Chicken nuggets")))
 (->html tx)
 (->html tx #:splice #t)
+(define x "Fancy sauce")
+(->html x)
+(code:comment @#,t{This next one won't do anything})
+(->html x #:splice #t)
+(code:comment @#,t{Adds the outer tag, but then #:splice removes it})
+(->html x #:tag 'div #:attrs '((id "doback")) #:splice #t)
 ]
 
 

template.rkt

@@ -77,13 +77,20 @@
 
 (define+provide/contract (->html x #:tag [tag #f] #:attrs [attrs #f] #:splice [splice? #f])
   ((xexpr?) (#:tag (or/c #f txexpr-tag?) #:attrs (or/c #f txexpr-attrs?) #:splice boolean?) . ->* . string?)
+
+  (when (and (not (txexpr? x)) attrs (not tag))
+      (error '->html "can't use attribute list '~a without a #:tag argument" attrs))
+      
+  (if (or tag (txexpr? x))
+      (let ()
         (define html-tag (or tag (get-tag x)))
-  (define html-attrs (or attrs (get-attrs x)))
-  (define html (xexpr->html (make-txexpr html-tag html-attrs (get-elements x))))
+        (define html-attrs (or attrs (and (txexpr? x) (get-attrs x)) null))
+        (define html-elements (or (and (txexpr? x) (get-elements x)) (list x)))
+        (define html (xexpr->html (make-txexpr html-tag html-attrs html-elements)))
         (if splice?
             (trim-outer-tag html)
             html))
-
+      (xexpr->html x)))  
 
 (provide when/block)
 (define-syntax (when/block stx)

tests/test-template.rkt

@@ -2,11 +2,20 @@
 (require rackunit)
 (require "../template.rkt")
 
-(define x '(root (p "hello")))
-
-(check-equal? (->html x) "<root><p>hello</p></root>")
-(check-equal? (->html #:tag 'brennan x) "<brennan><p>hello</p></brennan>")
-(check-equal? (->html #:attrs '((id "dale")) x) "<root id=\"dale\"><p>hello</p></root>")
-(check-equal? (->html #:splice #t x) "<p>hello</p>")
-(check-equal? (->html #:tag 'brennan #:attrs '((id "dale")) x) "<brennan id=\"dale\"><p>hello</p></brennan>")
-(check-equal? (->html #:tag 'brennan #:attrs '((id "dale")) #:splice #t x) "<p>hello</p>")
+(define tx '(root (p "hello")))
+
+(check-equal? (->html tx) "<root><p>hello</p></root>")
+(check-equal? (->html #:tag 'brennan tx) "<brennan><p>hello</p></brennan>")
+(check-equal? (->html #:attrs '((id "dale")) tx) "<root id=\"dale\"><p>hello</p></root>")
+(check-equal? (->html #:splice #t tx) "<p>hello</p>")
+(check-equal? (->html #:tag 'brennan #:attrs '((id "dale")) tx) "<brennan id=\"dale\"><p>hello</p></brennan>")
+(check-equal? (->html #:tag 'brennan #:attrs '((id "dale")) #:splice #t tx) "<p>hello</p>")
+
+(define x "hello")
+
+(check-equal? (->html x) "hello")
+(check-equal? (->html #:tag 'brennan x) "<brennan>hello</brennan>")
+(check-exn exn:fail? (λ() (->html #:attrs '((id "dale")) x) "hello")) ;; won't work without tag
+(check-equal? (->html #:splice #t x) "hello")
+(check-equal? (->html #:tag 'brennan #:attrs '((id "dale")) x) "<brennan id=\"dale\">hello</brennan>")
+(check-equal? (->html #:tag 'brennan #:attrs '((id "dale")) #:splice #t x) "hello")