* Add --list-backends option

        For issue #33

src/core/mgmt/ocarina-options.ads

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 S p e c                                  --
 --                                                                          --
---    Copyright (C) 2008-2009 Telecom ParisTech, 2010-2015 ESA & ISAE.      --
+--    Copyright (C) 2008-2009 Telecom ParisTech, 2010-2016 ESA & ISAE.      --
 --                                                                          --
 -- Ocarina  is free software; you can redistribute it and/or modify under   --
 -- terms of the  GNU General Public License as published  by the Free Soft- --
@@ -54,6 +54,7 @@ package Ocarina.Options is
       Show_Usage,
       Parse_Scenario_Files_First,
       Shell,
+      List_Backends,
       Python_Shell);
 
    After_Scenario_Action : Action_Kind := Generate_Code;

src/main/ocarina-cmd_line.adb

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---                     Copyright (C) 2015 ESA & ISAE.                       --
+--                   Copyright (C) 2015-2016 ESA & ISAE.                    --
 --                                                                          --
 -- Ocarina  is free software; you can redistribute it and/or modify under   --
 -- terms of the  GNU General Public License as published  by the Free Soft- --
@@ -105,6 +105,9 @@ package body Ocarina.Cmd_Line is
             Add_Library_Path (Parameter);
          end if;
 
+      elsif Switch = "--list-backends" then
+         Set_Current_Action (List_Backends);
+
       elsif Switch = "-o" then
          Output_Filename := Get_String_Name (Parameter);
          Generated_Sources_Directory := Output_Filename;
@@ -273,6 +276,10 @@ package body Ocarina.Cmd_Line is
       Define_Switch (Ocarina_Options, "-g:",
                      Help => "Generate code using Ocarina backend 'ARG'");
 
+      --  --list-backends flag
+      Define_Switch (Ocarina_Options, Long_Switch => "--list-backends",
+                     Help => "List available backends");
+
       --  -b flag
       Define_Switch (Ocarina_Options,
                      Backends.Compile_Generated_Sources'Access, "-b",

src/main/ocarina_cmd.adb

@@ -6,7 +6,7 @@
 --                                                                          --
 --                                 B o d y                                  --
 --                                                                          --
---    Copyright (C) 2004-2009 Telecom ParisTech, 2010-2015 ESA & ISAE.      --
+--    Copyright (C) 2004-2009 Telecom ParisTech, 2010-2016 ESA & ISAE.      --
 --                                                                          --
 -- Ocarina  is free software; you can redistribute it and/or modify under   --
 -- terms of the  GNU General Public License as published  by the Free Soft- --
@@ -559,8 +559,10 @@ begin
 
    if Verbose then
       Set_Standard_Error;
+      if not Display_Version then
          Version;
       end if;
+   end if;
 
    if Display_Version then
       Version;
@@ -570,6 +572,10 @@ begin
       Write_Line (Get_Name_String (Default_Library_Path));
       OS_Exit (0);
 
+   elsif Get_Current_Action = List_Backends then
+      Write_Backends (1);
+      OS_Exit (0);
+
    elsif Get_Current_Action = Shell then
       Ocarina_Shell;
       OS_Exit (0);