[Emacs-ada-mode] [Emacs][ada-mode] ada-xref.el -- missing gnatls in PATH

[Stephen Leake]

Stephen Leake <stephen_leake at stephe-leake.org> writes:

> Pierre-Louis Escouflaire <pierre-louis.escouflaire at eurocontrol.int> writes:
>
>>> I don't think there's any point in attempting to handle the error in
>>> ada-initialize-runtime-library; if gnatls isn't found, nothing else
>>> will work either, because gnat won't be found.
>>
>> This is perfectly correct... based on a developer's point of view.
>>
>> However, I think that Emacs should start properly:
>>    . for users that only need to read Ada sources,
>>    . for users in a restrained environment,
>>    . for users not using the GNAT compiler and tools.
>>
>> Thus, the 'ada-initialize-runtime-library' behavior might be to warn
>> users that some features are not available because of one of the two
>> last reasons.
>
> Hmm. I was assuming that if you are not using GNAT, you would not be
> using ada-xref. But that's false, since ada-xref provides project
> files, which support other compilers.
>
> We really should factor out the project file support from the GNAT
> support, but that's a lot of work.
>
>> An extension of this might be to enable/disable shortcuts, menu items,
>> etc. whether or not the user is in a restrained environments or
>> without the GNAT compiler and tools.
>
> Yes, this is the right approach.
>
> I'll see what I can do for a minimal fix at the moment.

Here's a patch.

There was code in ada-initialize-runtime-library that was trying to do
the right thing, but it wasn't working. Now it is.

In addition, ada-xref.el was running ada-initialize-runtime-library at
load time; it should wait until it's needed, since the user may
specify a cross-prefix.

I tested this with no GNAT in my path; Ada mode loads cleanly, code is
displayed with font-lock properly. Trying to use anything that needs
GNAT gives a fairly clear error message (ie "gnatkr not found").

It also works properly _with_ GNAT in my path :).

============================================================
--- emacs_stephe_site_lisp/ada-xref.el
+++ emacs_stephe_site_lisp/ada-xref.el
@@ -274,72 +274,73 @@ are retrieved with `ada-xref-get-project
 
 (defun ada-find-executable (exec-name)
   "Find the full path to the executable file EXEC-NAME.
+If not found, throw an error.
 On Windows systems, this will properly handle .exe extension as well"
-  (or (ada-find-file-in-dir exec-name exec-path)
-      (ada-find-file-in-dir (concat exec-name ".exe") exec-path)
-      exec-name))
+  (let ((result (or (ada-find-file-in-dir exec-name exec-path)
+                    (ada-find-file-in-dir (concat exec-name ".exe") exec-path))))
+    (if result
+        result
+      (error "'%s' not found in path" exec-name))))
 
 (defun ada-initialize-runtime-library (cross-prefix)
-  "Initialize the variables for the runtime library location.
-CROSS-PREFIX is the prefix to use for the `gnatls' command."
-  (let (gnatls)
-    (condition-case nil
-	;; if gnatls not found, just give up (may not be using GNAT)
-	(ada-find-executable (concat cross-prefix "gnatls"))
-      (error nil))
+  "Initialize the variables for the runtime library location."
+  (let ((gnatls
+         (condition-case nil
+             ;; if gnatls not found, just give up (may not be using GNAT)
+             (ada-find-executable (concat cross-prefix "gnatls"))
+           (error nil))))
+    (if gnatls
+        (save-excursion
+          (setq ada-xref-runtime-library-specs-path '()
+                ada-xref-runtime-library-ali-path   '())
+          (set-buffer (get-buffer-create "*gnatls*"))
+          (widen)
+          (erase-buffer)
+          ;;  Even if we get an error, delete the *gnatls* buffer
+          (unwind-protect
+              (let* ((status (call-process gnatls nil t nil "-v")))
+                (goto-char (point-min))
 
-    (save-excursion
-      (setq ada-xref-runtime-library-specs-path '()
-	    ada-xref-runtime-library-ali-path   '())
-      (set-buffer (get-buffer-create "*gnatls*"))
-      (widen)
-      (erase-buffer)
-      ;;  Even if we get an error, delete the *gnatls* buffer
-      (unwind-protect
-	  (let* ((gnatls (ada-find-executable (concat cross-prefix "gnatls")))
-		 (status (call-process gnatls nil t nil "-v")))
-	    (goto-char (point-min))
+                ;; Since we didn't provide all the inputs gnatls expects, it returns status 4
+                (if (/= 4 status)
+                    (error (buffer-substring (point) (line-end-position))))
 
-	    ;; Since we didn't provide all the inputs gnatls expects, it returns status 4
-	    (if (/= 4 status)
-		(error (buffer-substring (point) (line-end-position))))
+                ;;  Source path
 
-	    ;;  Source path
+                (search-forward "Source Search Path:")
+                (forward-line 1)
+                (while (not (looking-at "^$"))
+                  (back-to-indentation)
+                  (if (looking-at "<Current_Directory>")
+                      (add-to-list 'ada-xref-runtime-library-specs-path  ".")
+                    (add-to-list 'ada-xref-runtime-library-specs-path
+                                 (buffer-substring-no-properties
+                                  (point)
+                                  (save-excursion (end-of-line) (point)))))
+                  (forward-line 1))
 
-	  (search-forward "Source Search Path:")
-	  (forward-line 1)
-	  (while (not (looking-at "^$"))
-	    (back-to-indentation)
-	    (if (looking-at "<Current_Directory>")
-		(add-to-list 'ada-xref-runtime-library-specs-path  ".")
-	      (add-to-list 'ada-xref-runtime-library-specs-path
-			   (buffer-substring-no-properties
-			    (point)
-			    (save-excursion (end-of-line) (point)))))
-	    (forward-line 1))
+                ;;  Object path
 
-	  ;;  Object path
+                (search-forward "Object Search Path:")
+                (forward-line 1)
+                (while (not (looking-at "^$"))
+                  (back-to-indentation)
+                  (if (looking-at "<Current_Directory>")
+                      (add-to-list 'ada-xref-runtime-library-ali-path ".")
+                    (add-to-list 'ada-xref-runtime-library-ali-path
+                                 (buffer-substring-no-properties
+                                  (point)
+                                  (save-excursion (end-of-line) (point)))))
+                  (forward-line 1))
+                )
+            (kill-buffer nil))))
 
-	  (search-forward "Object Search Path:")
-	  (forward-line 1)
-	  (while (not (looking-at "^$"))
-	    (back-to-indentation)
-	    (if (looking-at "<Current_Directory>")
-		(add-to-list 'ada-xref-runtime-library-ali-path ".")
-	      (add-to-list 'ada-xref-runtime-library-ali-path
-			   (buffer-substring-no-properties
-			    (point)
-			    (save-excursion (end-of-line) (point)))))
-	    (forward-line 1))
-	  )
-	(kill-buffer nil))))
+    (set 'ada-xref-runtime-library-specs-path
+    (reverse ada-xref-runtime-library-specs-path))
+    (set 'ada-xref-runtime-library-ali-path
+    (reverse ada-xref-runtime-library-ali-path))
+    ))
 
-  (set 'ada-xref-runtime-library-specs-path
-       (reverse ada-xref-runtime-library-specs-path))
-  (set 'ada-xref-runtime-library-ali-path
-       (reverse ada-xref-runtime-library-ali-path))
-  )
-
 (defun ada-gnat-parse-gpr (plist gpr-file)
   "Set gpr_file, src_dir and obj_dir properties in PLIST by parsing GPR-FILE.
 Returns new value of PLIST.
@@ -2381,14 +2382,6 @@ For instance, it creates the gnat-specif
      'error-message
      "File not found in src-dir (check project file): ")
 
-;;  Initializes the cross references to the runtime library
-(ada-initialize-runtime-library "")
-
-;;  Add these standard directories to the search path
-(set 'ada-search-directories-internal
-     (append (mapcar 'directory-file-name ada-xref-runtime-library-specs-path)
-	     ada-search-directories))
-
 (provide 'ada-xref)

-- 
-- Stephe