From c63cd9a943cf09fe128519d08d530abf1c072fca Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Tue, 22 Jan 2008 14:54:37 +0000
Subject: [PATCH] fix eval:alts to not add context

svn: r8383

original commit: b7a19fdc4a19e7f62a6f47f05e4ea32b6d97b98b
---
 collects/scribble/eval.ss | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/collects/scribble/eval.ss b/collects/scribble/eval.ss
index 8c790915..441ed8d4 100644
--- a/collects/scribble/eval.ss
+++ b/collects/scribble/eval.ss
@@ -124,14 +124,21 @@
                    (cdr val-list+outputs)
                     #f)))))))
 
+  (define (extract s . ops)
+    (let loop ([s s][ops ops])
+      (cond
+       [(null? ops) s]
+       [(syntax? s) (loop (syntax-e s) ops)]
+       [else (loop ((car ops) s) (cdr ops))])))
+
   (define ((do-eval ev) s)
     (syntax-case s (code:comment eval:alts)
      [(code:line v (code:comment . rest))
-      ((do-eval ev) #'v)]
+      ((do-eval ev) (extract s cdr car))]
      [(code:comment . rest)
       (list (list (void)) "" "")]
      [(eval:alts p e)
-      ((do-eval ev) #'e)]
+      ((do-eval ev) (extract s cdr cdr car))]
      [else
       (with-handlers ([exn:fail? (lambda (e)
                                    (list (exn-message e)