From d892cb243e8b74377eae058ab431f5d1e796b1e1 Mon Sep 17 00:00:00 2001
From: Eli Barzilay <eli@racket-lang.org>
Date: Sun, 28 Sep 2008 20:43:13 +0000
Subject: [PATCH] * Move the help functionality into the search collection, so
 it is not   packaged with the mzscheme distribution * Make scheme/help throw
 a helpful message if the file is missing

svn: r11896
---
 .../help-autoload.ss => help/help-utils.ss}   | 17 +++++++-----
 collects/scheme/help.ss                       | 26 ++++++++++++++++---
 2 files changed, 34 insertions(+), 9 deletions(-)
 rename collects/{scheme/private/help-autoload.ss => help/help-utils.ss} (88%)

diff --git a/collects/scheme/private/help-autoload.ss b/collects/help/help-utils.ss
similarity index 88%
rename from collects/scheme/private/help-autoload.ss
rename to collects/help/help-utils.ss
index 0fb6813ab4..8e69e454cb 100644
--- a/collects/scheme/private/help-autoload.ss
+++ b/collects/help/help-utils.ss
@@ -1,15 +1,23 @@
 #lang scheme/base
 
+;; This file provides the utilities that mzscheme's `help' form uses.
+;; It is required dynamically when used from mzscheme, to avoid the
+;; loading overhead, and to have mzscheme independent of having the
+;; documentation system.
+
 (require setup/xref
          scribble/xref
          scribble/manual-struct
-         help/search
          net/uri-codec
          net/sendurl
          scheme/path
-         scheme/list)
+         scheme/list
+         "search.ss")
 
-(provide find-help find-help/lib search-for)
+(provide search-for find-help find-help/lib)
+
+(define (search-for strs)
+  (perform-search (apply string-append (add-between strs " "))))
 
 (define-namespace-anchor anchor)
 
@@ -62,6 +70,3 @@
     (when anchor (printf "  anchor: ~a\n" anchor))
     (unless (send-url/file file #:fragment (and anchor (uri-encode anchor)))
       (error 'help "browser launch failed"))))
-
-(define (search-for strs)
-  (perform-search (apply string-append (add-between strs " "))))
diff --git a/collects/scheme/help.ss b/collects/scheme/help.ss
index f8569728ee..da6966a0c4 100644
--- a/collects/scheme/help.ss
+++ b/collects/scheme/help.ss
@@ -39,10 +39,30 @@
 (define (open-help-start)
   (find-help #'help))
 
+;; Autoload utilities from help/help-utils; if it does not exists,
+;; suggest using docs.plt-scheme.org.
+
+(define-namespace-anchor anchor)
+(define get-binding
+  (let ([ns #f] [utils #f])
+    (lambda (sym)
+      (unless ns
+        (set! ns (namespace-anchor->empty-namespace anchor))
+        (set! utils (resolved-module-path-name
+                     (module-path-index-resolve
+                      (module-path-index-join 'help/help-utils #f)))))
+      (parameterize ([current-namespace ns])
+        (if (file-exists? utils)
+          (dynamic-require utils sym)
+          (lambda _
+            (error 'help "documentation system unavailable; ~a\n~a"
+                   "try http://docs.plt-scheme.org/"
+                   (format "  (missing file: ~a)" utils))))))))
+
 (define-syntax-rule (define-help-autoload id)
-  (begin
-    (define auto (delay (dynamic-require 'scheme/private/help-autoload 'id)))
-    (define (id . args) (apply (force auto) args))))
+  (define id
+    (let ([proc (delay (get-binding 'id))])
+      (lambda args (apply (force proc) args)))))
 
 (define-help-autoload find-help)
 (define-help-autoload find-help/lib)