I currently use the A.vim plugin to swap between header and implementation file. The limitation of this script is that it only works if both are in the same folder.
If you have a cscope database for your code you can easily find the header for a particular implementation file by doing :cscope find f ImplementationFileName.h
.
How would you script this to take the current file name without the extension and search for that name with the added .h suffix?
This should be possible out of the box using A.vim. Check out :help alternate-config. Specifically the section on search paths: