scribble/reader: allow escape character to be non-ASCII

original commit: 96c5521196dc1fe19c401950775b2c8f8e80991f

collects/scribblings/scribble/reader-internals.scrbl

@@ -198,7 +198,7 @@ Useful for implementing languages that are textual by default (see
 
 @defproc[(make-at-readtable
           [#:readtable readtable readtable? (current-readtable)]
-          [#:command-char command-char character? #\@]
+          [#:command-char command-char char? #\@]
           [#:datum-readtable datum-readtable
                              (or/c readtable? boolean?
                                               (readtable? . -> . readtable?))

collects/tests/scribble/docs/diamond.rkt

@@ -0,0 +1,15 @@
+#lang racket/base
+(require (only-in scribble/reader make-at-readtable))
+
+(provide (rename-out [diamond-read read]
+                     [diamond-read-syntax read-syntax]))
+
+(define diamond-readtable (make-at-readtable #:command-char #\◇))
+
+(define (diamond-read p)
+  (parameterize ([current-readtable diamond-readtable])
+    (read p)))
+
+(define (diamond-read-syntax name p)
+  (parameterize ([current-readtable diamond-readtable])
+    (read-syntax name p)))

collects/tests/scribble/docs/diamond.scrbl

@@ -0,0 +1,14 @@
+#lang scribble/base
+@#reader "diamond.rkt"
+
+◇begin{
+  
+ This example checks that @ is not an escape character
+ if we make a reader that uses a different escape character.
+
+ ◇(define ch "diamond")
+
+ It also makes sure that a non-ASCII character like ◇ch
+ is ok as an escape character.
+
+ }

collects/tests/scribble/docs/diamond.txt

@@ -0,0 +1,5 @@
+This example checks that @ is not an escape character if we make a
+reader that uses a different escape character.
+
+It also makes sure that a non-ASCII character like diamond is ok as an
+escape character.