Greg >Apex does not use a project mechanism. If the compiler sees a >with clause, it knows what the file name must be, and then searches >the imported subsystems/views for it. There is no need to register >files, or have project mechanims etc. So long as the source code >files are named correctly and are located in a subsystem/view the >compiler will find them. This is why Apex can perform it's automated >builds. So what is the difference between "registering files" and "importing subsystems/views" from an Ada source code perspective? Very little it would seems. I haven't used Apex, but how does it handle multi-compilation unit files? Does it have the same restrictions as GNAT (i.e. one compilation unit per file)? If this is true, then I would guess that the Apex mechanism is not that different to the ada-mode mechanisms for Projects using Emacs and GNAT. John