- fixed usage string,

- improved the "use hint" displayed at the end, and moved the code
  producing it to a separate function,
- made "--help" work even when no "pkg-def.scm" file is found.

scheme/install-lib/install-lib.scm

@@ -1,5 +1,5 @@
 ;;; Installation library for scsh modules.
-;;; $Id: install-lib.scm,v 1.13 2004/03/14 14:10:25 michel-schinz Exp $
+;;; $Id: install-lib.scm,v 1.14 2004/03/31 19:44:54 michel-schinz Exp $
 
 ;; TODO
 ;; - think about --host: does it make sense?
@@ -428,7 +428,8 @@
 (define (load-packages)
   (let-fluid *packages* (make-cell '())
              (lambda ()
-               (load-quietly package-definition-file)
+               (if (file-exists? package-definition-file)
+                   (load-quietly package-definition-file))
                (cell-ref (fluid *packages*)))))
 
 ;; Like load-package but check additionally that none of the loaded
@@ -529,12 +530,14 @@
 ;; Load script handling
 ;;
 
+(define load-script-name "load.scm")
+
 ;; Evaluate THUNK with CURRENT-OUTPUT-PORT opened on the current
 ;; package's loading script (in the install directory). During a dry
 ;; run, or when only non-shared data has to be installed, do nothing.
 (define (with-output-to-load-script* thunk)
   (let* ((dir (get-directory 'base #t))
-         (file (absolute-file-name "load.scm" dir)))
+         (file (absolute-file-name load-script-name dir)))
     (create-directory&parents dir)
     (if (not (or (get-option-value 'dry-run)
                  (get-option-value 'non-shared-only)))
@@ -750,7 +753,7 @@ advanced options:
   --build <name>       name of platform for which to build
   --layout-from <file> load layout of installation directory from file
   --layout-to <file>   output layout to given file
-  --install-prefix <dir>  specify prefix to used during installation
+  --dest-dir <dir>     specify prefix to used during installation
                        (to be used only during staged installations)
 
 END
@@ -789,6 +792,47 @@ END
   (newline)
   (exit 1))
 
+;; Display a hint about how to use the just-installed PACKAGES,
+;; assuming they were laid out according to LAYOUT and PREFIX.
+(define (display-use-hint prefix layout packages)
+  (let* ((active-locations (delete-duplicates
+                            (map (lambda (pkg)
+                                   (string-append "\""
+                                                  (layout-dir (absolute-layout
+                                                               (layout pkg)
+                                                               prefix)
+                                                              'active)
+                                                  "\""))
+                                 packages)
+                            string=?))
+         (load-scripts (map (lambda (pkg)
+                              (absolute-file-name load-script-name
+                                                  (package-name pkg)))
+                            packages))
+         (scsh-options (map (lambda (load-script)
+                              (string-append "-lel " load-script))
+                            load-scripts)))
+    (display
+     (as-string
+      "The following scsh package" (if (many? packages) "s were" " was")
+      " installed successfully:\n"
+      "  "(string-join (map package-full-name packages) ", ")"\n"))
+    (if (not (find-library-file (first load-scripts) (lib-dirs) ""))
+        (display
+         (as-string
+          "To make sure scsh finds "(if (many? packages) "them" "it")", "
+          "please add the following value"
+          (if (many? active-locations) "s" "")"\n"
+          "to the environment variable SCSH_LIB_DIRS (quotes included):\n"
+          "  " (string-join active-locations " ") "\n")))
+    (display
+     (as-string
+      "To use "
+      (if (many? packages) "these packages" "this package")
+      " in a script, invoke scsh with the following option"
+      (if (many? scsh-options) "s" "")":\n"
+      "  "(string-join scsh-options " ")"\n"))))
+
 ;;
 ;; Command line parsing
 ;;
@@ -885,9 +929,6 @@ END
     (exclude         . ,(lambda args #f))))
 
 (define (install-main cmd-line)
-  (if (not (file-exists? package-definition-file))
-      (display-error-and-exit "cannot find package definition file"
-                              "("package-definition-file")"))
   (let* ((packages (load&check-packages))
          (all-pkg-opts (all-package-options packages)))
     (if (not (null? all-pkg-opts))
@@ -905,6 +946,14 @@ END
                                           all-dfts))
            (prefix (alist-get 'prefix options-values))
            (layout (alist-get 'layout options-values)))
+      (if (null? packages)
+          (display-error-and-exit
+           "no package to install"
+           (if (not (file-exists? package-definition-file))
+               (as-string "\n(cannot find file called \""
+                          package-definition-file
+                          "\" in current directory)")
+               "")))
       (if (not prefix)
           (display-error-and-exit "no prefix specified (use --prefix option)"))
       (if (not (file-name-absolute? prefix))
@@ -913,25 +962,4 @@ END
         (if (not resolved-layout)
             (display-error-and-exit "invalid layout "layout))
         (install-packages packages options-values)
-        (let ((active-locations
+        (display-use-hint prefix resolved-layout packages)))))
-               (delete-duplicates
-                (map (lambda (pkg)
-                       (string-append "\""
-                                      (layout-dir (absolute-layout
-                                                   (resolved-layout pkg)
-                                                   prefix)
-                                                  'active)
-                                      "\""))
-                     packages)
-                string=?)))
-          (display
-           (as-string
-            "The following scsh package" (if (many? packages) "s were" " was")
-            " installed successfully:\n"
-            "  "(string-join (map package-full-name packages) ", ")"\n"
-            "In order to use "(if (many? packages) "them" "it")", "
-            "make sure to add the following value"
-            (if (many? active-locations) "s" "")"\n"
-            "to the environment variable SCSH_LIB_DIRS (quotes included):\n"
-            "  " (string-join active-locations " ")
-            "\n")))))))