From: Ferenc Engard <ferenc@...>
Date: 2003-10-09T08:50:56+09:00
Subject: exception backtrace for ruby/tk programs

Hello,

I suffered with really hard debugging sessions when an unexpected
exception was thrown from a ruby callback in a ruby/tk application, as
the tk error dialog box showed only the error message itself and no
backtrace. I have had to modify TkCore.callback() to reveal the
backtrace.

Don't you miss this information? Can this be done in another way? If
not, then here is the simple patch, maybe it can be put into the
mainstream code.

------------------------------------------------------------------
root@domesticus:/usr/lib/ruby/1.8# diff -u tk.rb.old tk.rb
--- tk.rb.old   2003-10-09 01:18:38.000000000 +0200
+++ tk.rb       2003-10-09 01:40:47.000000000 +0200
@@ -772,7 +772,13 @@
    
#_get_eval_string(TkUtil.eval_cmd(TkCore::INTERP.tk_cmd_tbl[arg.shift],
     #                               *arg))
     cb_obj = TkCore::INTERP.tk_cmd_tbl[arg.shift]
-    cb_obj.call(*arg)
+    begin
+      cb_obj.call(*arg)
+    rescue
+      # Append the backtrace to the message, so it can be displayed in
the
+      # Tk error dialog window.
+      raise $!, "#{$!} - backtrace: \n#{$!.backtrace.join("\n")}"
+    end
   end

   def load_cmd_on_ip(tk_cmd)
------------------------------------------------------------------

Bye:
Ferenc