scribble: change Latex rendering of empty hidden part titles

original commit: fc1089c84220582e627e0931438c275965228550

collects/scribble/latex-render.rkt

@@ -130,7 +130,10 @@
           (printf "\n\n\\postDoc\n\\end{document}\n"))))
 
     (define/override (render-part-content d ri)
-      (let ([number (collected-info-number (part-collected-info d ri))])
+      (let ([number (collected-info-number (part-collected-info d ri))]
+            [completely-hidden?
+             (and (part-style? d 'hidden)
+                  (equal? "" (content->string (part-title-content d))))])
         (when (and (part-title-content d) 
                    (or (pair? number)
                        (let ([d (render-part-depth)])
@@ -141,6 +144,10 @@
             (for ([pre (in-list pres)])
               (printf "\n\n")
               (do-render-paragraph pre d ri #t #f)))
+          (cond
+           [completely-hidden?
+            (printf "\n\n\\notitlesection")]
+           [else
             (let ([no-number? (and (pair? number) 
                                    (or (not (car number))
                                        ((length number) . > . 3)))])
@@ -162,9 +169,10 @@
             (printf "{")
             (render-content (part-title-content d) d ri)
             (printf "}")
-          (when (eq? (style-name (part-style d)) 'index) (printf "\n\n")))
+            (when (eq? (style-name (part-style d)) 'index) (printf "\n\n"))]))
         (for ([t (part-tags d)])
-          (printf "\\label{t:~a}\n\n" (t-encode (add-current-tag-prefix (tag-key t ri)))))
+          (printf "\\label{t:~a}~a" (t-encode (add-current-tag-prefix (tag-key t ri)))
+                  (if completely-hidden? "" "\n\n")))
         (render-flow (part-blocks d) d ri #f)
         (for ([sec (part-parts d)]) (render-part sec ri))
         (when (eq? (style-name (part-style d)) 'index) (printf "\\onecolumn\n\n"))

collects/scribble/scribble.tex

@@ -145,6 +145,9 @@
 \newcommand{\subsectionhidden}[1]{\subsection{#1}}
 \newcommand{\subsubsectionhidden}[1]{\subsubsection{#1}}
 
+% For hidden parts with an empty title:
+\newcommand{\notitlesection}{\vspace{2ex}\phantomsection\noindent}
+
 % When brackets appear in section titles:
 \newcommand{\SOpenSq}{[}
 \newcommand{\SCloseSq}{]}

collects/scribblings/scribble/core.scrbl

@@ -342,7 +342,8 @@ The recognized @tech{style properties} are as follows:
        normally shows only the top-level sections).}
 
  @item{@racket['hidden] --- The part title is not shown in rendered
-       HTML output. The @racket['toc-hidden] style usually should be
+       HTML output, and the part title is not shown in Latex output if it
+       is empty. The @racket['toc-hidden] style usually should be
        included with @racket['hidden].}
 
  @item{@racket['toc-hidden] --- The part title is not shown in tables