add x-source-pkg to HTML output

scribble-doc/scribblings/scribble/core.scrbl

@@ -1587,12 +1587,14 @@ other documents can link to the section.
 
 More specifically, the section title is given the HTML attributes
 @tt{x-source-module} and @tt{x-part-tag}, plus @tt{x-part-prefixes}
-if the section or enclosing sections declare tag prefixes. The
+if the section or enclosing sections declare tag prefixes, and
+@tt{x-source-pkg} if the source is found within a package at document-build time. The
 @racketmodname[scribble/manual] style recognizes those tags to make
 clicking a title show cross-reference information.
 
 @history[#:added "1.2"
-         #:changed "1.7" @elem{Added @tt{x-part-prefixes}.}]}
+         #:changed "1.7" @elem{Added @tt{x-part-prefixes}.}
+         #:changed "1.9" @elem{Added @tt{x-source-pkg}.}]}
 
 
 @defstruct[html-defaults ([prefix (or/c bytes? path-string? 

scribble-lib/info.rkt

@@ -22,4 +22,4 @@
 
 (define pkg-authors '(mflatt eli))
 
-(define version "1.8")
+(define version "1.9")

scribble-lib/scribble/html-render.rkt

@@ -19,6 +19,7 @@
          net/base64
          scheme/serialize
          racket/draw/gif
+         pkg/path
          (prefix-in xml: xml/xml)
          (for-syntax scheme/base)
          "search.rkt"
@@ -312,6 +313,7 @@
              root-relative?)
 
     (define path-cache (make-hash))
+    (define pkg-cache (make-hash))
 
     (define (path->relative p)
       (let ([p (path->main-doc-relative p)])
@@ -1116,6 +1118,14 @@
                                                (cadr t)))])
                             (if (and src taglet)
                                 `([x-source-module ,(format "~s" src)]
+                                  ,@(let* ([path (resolved-module-path-name
+                                                  (module-path-index-resolve
+                                                   (module-path-index-join src #f)))]
+                                           [pkg (and (path? path)
+                                                     (path->pkg path #:cache pkg-cache))])
+                                      (if pkg
+                                          `([x-source-pkg ,pkg])
+                                          null))
                                   ,@(let ([prefixes (current-tag-prefixes)])
                                       (if (null? prefixes)
                                           null