scribble: add support for setting a document date

in Latex output, and also document and generalize
 the 'pretitle paragraph style

collects/scribble/base-render.rkt

@@ -144,6 +144,12 @@
                  (style-properties (part-style d)))
           ""))
 
+    (define/public (extract-date d)
+      (ormap (lambda (v)
+               (and (document-date? v)
+                    (document-date-text v)))
+             (style-properties (part-style d))))
+
     (define/private (extract-pre-paras d sym)
       (let loop ([l (part-blocks d)])
         (cond

collects/scribble/base.rkt

@@ -27,7 +27,8 @@
              (#:tag (or/c #f string? (listof string?))
                     #:tag-prefix (or/c #f string? module-path?)
                     #:style (or/c style? string? symbol? (listof symbol?) #f)
-                    #:version (or/c string? #f))
+                    #:version (or/c string? #f)
+                    #:date (or/c string? #f))
              #:rest (listof pre-content?)
              title-decl?)]
  [section (title-like-contract)]
@@ -60,12 +61,18 @@
    [else (raise-type-error who "style, string, symbol, list of symbols, or #f" s)]))
 
 (define (title #:tag [tag #f] #:tag-prefix [prefix #f] #:style [style plain]
-               #:version [version #f] . str)
+               #:version [version #f] #:date [date #f]
+               . str)
   (let ([content (decode-content str)])
     (make-title-decl (prefix->string prefix)
                      (convert-tag tag content)
                      version
-                     (convert-part-style 'title style)
+                     (let ([s (convert-part-style 'title style)])
+                       (if date
+                           (make-style (style-name s)
+                                       (cons (make-document-date date)
+                                             (style-properties s)))
+                           s))
                      content)))
 
 (define (section #:tag [tag #f] #:tag-prefix [prefix #f] #:style [style plain]

collects/scribble/core.rkt

@@ -176,6 +176,7 @@
          [properties list?])]
  ;; properties:
  [document-version ([text (or/c string? false/c)])]
+ [document-date ([text (or/c string? false/c)])]
  [target-url ([addr path-string?])]
  [color-property ([color (or/c string? (list/c byte? byte? byte?))])]
  [background-color-property ([color (or/c string? (list/c byte? byte? byte?))])]

collects/scribble/latex-render.rkt

@@ -49,6 +49,7 @@
              format-number
              extract-part-style-files
              extract-version
+             extract-date
              extract-authors
              extract-pretitle)
 
@@ -93,10 +94,13 @@
         (printf "\\begin{document}\n\\preDoc\n")
         (when (part-title-content d)
           (let ([vers (extract-version d)]
+                [date (extract-date d)]
                 [pres (extract-pretitle d)]
                 [auths (extract-authors d)])
             (for ([pre (in-list pres)])
+              (printf "\n\n")
               (do-render-paragraph pre d ri #t))
+            (when date (printf "\\date{~a}\n" date))
             (printf "\\titleAnd~aVersionAnd~aAuthors{" 
                     (if (equal? vers "") "Empty" "")
                     (if (null? auths) "Empty" ""))
@@ -115,6 +119,10 @@
         (when (and (part-title-content d) (pair? number))
           (when (eq? (style-name (part-style d)) 'index)
             (printf "\\twocolumn\n\\parskip=0pt\n\\addcontentsline{toc}{section}{Index}\n"))
+          (let ([pres (extract-pretitle d)])
+            (for ([pre (in-list pres)])
+              (printf "\n\n")
+              (do-render-paragraph pre d ri #t)))
           (let ([no-number? (and (pair? number) 
                                  (or (not (car number))
                                      ((length number) . > . 3)))])

collects/scribblings/scribble/base.scrbl

@@ -65,6 +65,7 @@ have @racketmodname[scribble/manual]).
                 [#:tag-prefix tag-prefix (or/c false/c string? module-path?) #f]
                 [#:style style (or/c style? #f string? symbol? (listof symbol?)) #f]
                 [#:version vers (or/c string? false/c) #f]
+                [#:date date (or/c string? false/c) #f]
                 [pre-content pre-content?] ...+)
          title-decl?]{
 
@@ -92,6 +93,11 @@ The @racket[vers] argument is propagated to the @racket[title-decl]
 structure. Use @racket[""] as @racket[vers] to suppress version
 rendering in the output.
 
+The @racket[date] argument is propagated to the @racket[title-decl]
+structure via a @racket[document-date] @tech{style property}. Use
+@racket[""] as @racket[date] to suppress date rendering in Latex
+output.
+
 The section title is automatically indexed by
 @racket[decode-part]. For the index key, leading whitespace and a
 leading ``A'', ``An'', or ``The'' (followed by more whitespace) is

collects/scribblings/scribble/core.scrbl

@@ -369,6 +369,13 @@ The recognized @tech{style properties} are as follows:
        attached to a part representing the whole document. The default
        version for a document is @racket[(version)].}
 
+ @item{@racket[document-date] structure --- A date for the part,
+       normally used on a document's main part for for Latex
+       output. The default date for a document is @racket[#f], which
+       avoids explicitly specifying a date at the Latex level, so that
+       the current date is used as the document date. Set the date to
+       @racket[""] to suppress a date in an output document.}
+
   @item{@racket[body-id] structure --- Generated HTML uses the given
         string @tt{id} attribute of the @tt{body} tag; this style can
         be set separately for parts that start different HTML pages,
@@ -408,6 +415,9 @@ recognized:
        by the Latex renderer by moving the author information to the
        title.}
 
+ @item{@racket['pretitle] --- Typeset before the title of the
+       enclosing part.}
+
 ]
 
 The currently recognized @tech{style properties} are as follows:
@@ -918,10 +928,16 @@ than a file path.}
 
 @defstruct[document-version ([text (or/c string? false/c)])]{
 
-Used as a @tech{style property} for a @racket[path] to indicate a
+Used as a @tech{style property} for a @racket[part] to indicate a
 version number.}
 
 
+@defstruct[document-date ([text (or/c string? false/c)])]{
+
+Used as a @tech{style property} for a @racket[part] to indicate a
+date (which is typically used for Latex output).}
+
+
 @defstruct[color-property ([color (or/c string? (list/c byte? byte? byte?))])]{
 
 Used as a @tech{style property} for an @racket[element] to set its