multiple sections and `page-side-start` attribute (closes #26)

quad/qtest/test-sections.rkt

@@ -4,4 +4,4 @@
 
 '(q ((break "section")))
 
-'(q ((page-width "5in")(page-height "3in")) "Second")
+'(q ((page-width "5in")(page-height "5in")(page-number-start "5")(page-side-start "right")) "Second")

quad/quad/scribblings/quad.scrbl

@@ -444,6 +444,13 @@ The @tech{Q-expression} @racketresult['#,para-break]. Used to denote the start o
 }
 
 
+@defthing[section-break qexpr?]{
+The @tech{Q-expression} @racketresult['#,section-break]. Used to denote the start of a new section.
+
+A section is a contiguous series of pages. Each section has its own @secref{Page-level_attributes}. A document without any explicit section breaks still has one section (that includes all the pages).
+}
+
+
 @subsection{Attributes}
 
 These are the attributes that can be used inside a @tech{Q-expression} passed to @racketmodname[quadwriter]. Inside a Q-expression, every attribute is a @tech[#:doc '(lib "scribblings/guide/guide.scrbl")]{symbol}, and every attribute value is a @tech[#:doc '(lib "scribblings/guide/guide.scrbl")]{string}.
@@ -481,7 +488,11 @@ Inset values from the page edges. Value is given as a @tech{dimension string}. D
 }
 
 @defthing[#:kind "attribute" page-number-start symbol?]{
-First page number used in document.
+First page number used. Default is @racket[1].
+}
+
+@defthing[#:kind "attribute" page-side-start symbol?]{
+Side that first page appears on. Can be @racket['left] or @racket['right]. A blank page will be inserted if necessary. Default is @racket['right].
 }
 
 @deftogether[(@defthing[#:kind "attribute" column-count symbol?]

quad/quadwriter/attrs.rkt

@@ -147,7 +147,9 @@ Naming guidelines
                            page-height
                            page-size ; e.g., "letter"
                            page-orientation ; only applies to page-size dimensions
+
                            page-number-start ; 1
+                           page-side-start ; 'right
 
                            page-margin-top
                            page-margin-bottom

quad/quadwriter/param.rkt

@@ -10,6 +10,8 @@
          (define current-doc (make-parameter #false))
          (define current-pdf (make-parameter #false))
          (define current-line-wrap (make-parameter #f)) ; because kp is slow and maybe we want to disable for "draft" mode
+         (define current-page-count (make-parameter 0))
+         
          (define quadwriter-test-mode (make-parameter #f)) ; used during rackunit to suppress nondeterministic elements, like timestamp in header
 
          (define draw-debug? (make-parameter #true))
@@ -32,6 +34,8 @@
          (define current-doc (make-parameter #false))
          (define current-pdf (make-parameter #false))
          (define current-line-wrap (make-parameter #f))
+         (define current-page-count (make-parameter 0))
+         
          (define quadwriter-test-mode (make-parameter #f))
 
          (define draw-debug? (make-parameter #false))

quad/quadwriter/render.rkt

@@ -169,7 +169,8 @@
 (define (setup-column-gap qs)
   (or (debug-column-gap)  (quad-ref (car qs) :column-gap default-column-gap)))
 
-(define/contract (render-pdf qx-arg pdf-path-arg [base-dir-arg #f]
+(define/contract (render-pdf qx-arg pdf-path-arg
+                             [base-dir-arg #false]
                              #:replace [replace-existing-file? #t]
                              #:compress [compress? #t])
   ((qexpr? (or/c #false path? path-string?))
@@ -194,6 +195,7 @@
                  ;; set `current-directory` so that ops like `path->complete-path`
                  ;; will be handled relative to the original directory
                  [current-directory base-dir]
+                 [current-page-count 0]
                  [verbose-quad-printing? #false])
     (define qs (time-log setup-qs (setup-qs qx-arg pdf-path)))
     (define sections
@@ -216,9 +218,24 @@
         (define page-quad-prototype (struct-copy quad q:page
                                                  [shift (pt left-margin top-margin)]
                                                  [size (pt line-wrap-size printable-height)]))
-                (define page-qs (time-log page-wrap (page-wrap column-qs printable-width page-quad-prototype)))
 
-                (struct-copy quad q:section [elems page-qs])))
+        (define next-page-side (if (even? (add1 (current-page-count))) 'left 'right))
+        (define insert-blank-page?
+          (and (pair? qs)
+               (let ([section-starting-side (string->symbol (quad-ref (car qs) :page-side-start "right"))])
+                 ;; if we need a 'left page and will get 'right (or vice versa) then insert page
+                 (not (eq? section-starting-side next-page-side)))))
+        
+        (define page-qs
+          (match (time-log page-wrap (page-wrap column-qs printable-width page-quad-prototype))
+            [ps #:when insert-blank-page?
+                (define blank-page (struct-copy quad (car ps) [elems null]))
+                (cons blank-page ps)]
+            [ps ps]))
+        
+        (begin0        
+          (struct-copy quad q:section [elems page-qs])
+          (current-page-count (+ (current-page-count) (length page-qs))))))
 
     (define doc (time-log position (position (struct-copy quad q:doc [elems sections]))))
     (time-log draw (draw doc (current-pdf))))