From 2d86232ba0eca052df4443ceef9a88c41688aa90 Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Wed, 29 Jul 2009 17:39:03 +0000
Subject: [PATCH] add file-or-directory-identity (4.1.2.5)

svn: r15623

original commit: a47d94f75f4099c5fcc1ed8a85fad456a0d7537f
---
 collects/scribble/decode.ss                | 22 ++++++++++++++++------
 collects/scribblings/scribble/decode.scrbl | 13 ++++++-------
 2 files changed, 22 insertions(+), 13 deletions(-)

diff --git a/collects/scribble/decode.ss b/collects/scribble/decode.ss
index 58834435..ee64f3c9 100644
--- a/collects/scribble/decode.ss
+++ b/collects/scribble/decode.ss
@@ -11,7 +11,8 @@
       (and (content? i)
            (not (list? i)))
       (and (splice? i)
-           (andmap pre-content? (splice-run i)))))
+           (andmap pre-content? (splice-run i)))
+      (void? i)))
 
 (define (pre-flow? i)
   (or (string? i)
@@ -19,7 +20,8 @@
            (not (list? i)))
       (block? i)
       (and (splice? i)
-           (andmap pre-flow? (splice-run i)))))
+           (andmap pre-flow? (splice-run i)))
+      (void? i)))
 
 (define (pre-part? v)
   (or (pre-flow? v)
@@ -150,6 +152,8 @@
               l))
           (decode-accum-para accum)
           null))]
+      [(void? (car l))
+       (loop (cdr l) next? keys colls accum title tag-prefix tags vers style)]
       [(title-decl? (car l))
        (cond [(not part-depth) (error 'decode "misplaced title: ~e" (car l))]
              [title (error 'decode "found extra title: ~v" (car l))]
@@ -267,6 +271,7 @@
 
 (define (match-newline-whitespace l)
   (cond [(null? l) #f]
+        [(void? (car l)) (match-newline-whitespace (cdr l))]
         [(line-break? (car l)) (skip-whitespace l)]
         [(splice? (car l))
          (match-newline-whitespace (append (splice-run (car l)) (cdr l)))]
@@ -274,9 +279,11 @@
         [else #f]))
 
 (define (skip-whitespace l)
-  (if (or (null? l) (not (whitespace? (car l))))
-    l
-    (skip-whitespace (cdr l))))
+  (if (or (null? l) 
+          (not (or (whitespace? (car l))
+                   (void? (car l)))))
+      l
+      (skip-whitespace (cdr l))))
 
 (define (decode l)
   (decode-part l null #f 0))
@@ -285,7 +292,10 @@
   (make-paragraph plain (decode-content l)))
 
 (define (decode-content l)
-  (append-map (lambda (s) (if (string? s) (decode-string s) (list s)))
+  (append-map (lambda (s) (cond
+                           [(string? s) (decode-string s)]
+                           [(void? s) null]
+                           [else (list s)]))
               (skip-whitespace l)))
 
 (define (decode-compound-paragraph l)
diff --git a/collects/scribblings/scribble/decode.scrbl b/collects/scribblings/scribble/decode.scrbl
index 07d46937..292bc6a7 100644
--- a/collects/scribblings/scribble/decode.scrbl
+++ b/collects/scribblings/scribble/decode.scrbl
@@ -59,9 +59,9 @@ Pre-content is decoded into @tech{content} by functions like
 @defproc[(pre-flow? [v any/c]) boolean?]{
 
 Returns @scheme[#t] if @scheme[v] is a @deftech{pre-flow} value: a
-string or other non-list @scheme[content], a @scheme[block], or a
-@scheme[splice] containing a list of @tech{pre-flow} values; otherwise
-returns @scheme[#f].
+string or other non-list @scheme[content], a @scheme[block],
+@|void-const|, or a @scheme[splice] containing a list of
+@tech{pre-flow} values; otherwise returns @scheme[#f].
 
 Pre-flow is decoded into a @tech{flow} (i.e., a list of @tech{blocks})
 by functions like @scheme[decode-flow].}
@@ -73,8 +73,8 @@ Returns @scheme[#t] if @scheme[v] is a @deftech{pre-part} value: a
 string or other non-list @scheme[content], a @scheme[block], a
 @scheme[part], a @scheme[title-decl], a @scheme[part-start], a
 @scheme[part-index-decl], a @scheme[part-collect-decl], a
-@scheme[part-tag-decl], or a @scheme[splice] containing a list of
-@tech{pre-part} values; otherwise returns @scheme[#f].
+@scheme[part-tag-decl], @|void-const|, or a @scheme[splice] containing
+a list of @tech{pre-part} values; otherwise returns @scheme[#f].
 
 A pre-part sequences is decoded into a @scheme[part] by functions like
 @scheme[decode] and @scheme[decode-part].}
@@ -93,9 +93,8 @@ of @scheme[part-tag-decl] add hyperlink tags to the section
 title. Instances of @scheme[part-start] at level 0 trigger sub-part
 parsing. Instances of @scheme[section] trigger are used as-is as
 subsections, and instances of @scheme[paragraph] and other
-flow-element datatypes are used as-is in the enclosing flow.
+flow-element datatypes are used as-is in the enclosing flow.}
 
-}
 
 @defproc[(decode-part [lst (listof pre-part?)]
                       [tags (listof string?)]