changed the meaning of one of the pretty-print parameters slightly and used that to fix redex's stepper

svn: r15419

collects/mzlib/pretty.ss

@@ -1186,7 +1186,7 @@
    (define (read-macro? l pair? car cdr)
      (define (length1? l) (and (pair? l) (null? (cdr l))))
      (and (pretty-print-abbreviate-read-macros)
-          (let ((head (car l)) (tail (cdr l)))
+          (let ((head (do-remap (car l))) (tail (cdr l)))
             (case head
               ((quote quasiquote unquote unquote-splicing syntax unsyntax unsyntax-splicing)
                (length1? tail))
@@ -1196,7 +1196,7 @@
      (car (cdr l)))
   
    (define (read-macro-prefix l car)
-     (let ((head (car l)))
+     (let ((head (do-remap (car l))))
        (case head
 	 ((quote)             "'")
 	 ((quasiquote)        "`")

collects/redex/private/sexp-diffs.ss

@@ -56,6 +56,7 @@
        (list->vector (map loop (vector->list s)))]
       [(box? s)
        (box (loop (unbox s)))]
+      [(syntax? s) (datum->syntax s (unkink (loop (syntax-e s))) s)]
       [(number? s) (make-wrap s)]
       [(symbol? s) (make-wrap s)]
       [else s])))
@@ -89,8 +90,7 @@
 ;; render-sexp/colors : sexp ht text -> void
 (define (render-sexp/colors sexp to-color text columns)
   (let ([start '()])
-    (parameterize ([pretty-print-columns columns]
-                   [pretty-print-abbreviate-read-macros #f])
+    (parameterize ([pretty-print-columns columns])
       (pretty-print sexp (open-output-text-editor text)))
     (for-each 
      (λ (p) (send text highlight-range (car p) (cdr p) (send the-color-database find-color "NavajoWhite")))
@@ -122,7 +122,6 @@
                                  1]))
                             void)])
     (parameterize ([pretty-print-columns columns]
-                   [pretty-print-abbreviate-read-macros #f]
                    [pretty-print-remap-stylable
                     (λ (val)
                       (and (wrap? val)

collects/scribblings/reference/pretty-print.scrbl

@@ -117,7 +117,10 @@ printed with a leading @litchar{#i}. The initial value is @scheme[#f].}
 A parameter that controls whether or not @schemeidfont{quote},
 @schemeidfont{unquote}, @schemeidfont{unquote-splicing}, @|etc| are
 abbreviated with @litchar{'}, @litchar{,}, @litchar[",@"], etc. 
-By default, the abbreviations are enabled.}
+By default, the abbreviations are enabled.
+
+See also @scheme[pretty-print-remap-stylable].
+}
 
 
 @defproc[(pretty-print-style-table? [v any/c]) boolean?]{
@@ -179,11 +182,17 @@ so that the output follows popular code-formatting rules:
           proc 
           (any/c . -> . (or/c symbol? #f))]{
 
-A parameter that controls remapping for styles. This procedure is
+A parameter that controls remapping for styles and for the determination of 
+the reader shorthands.
+
+This procedure is
 called with each subexpression that appears as the first element in a
 sequence. If it returns a symbol, the style table is used, as if that
 symbol were at the head of the sequence. If it returns @scheme[#f],
-the style table is treated normally.}
+the style table is treated normally.
+Similarly, when determining whether or not to abbreviate reader macros,
+the parameter is consulted.
+}
 
 
 @; ----------------------------------------------------------------------