fun! CleverTab()
	if col('.') > 1
		let beginning = strpart( getline('.'), 0, col('.')-1 )
	else
		let beginning = ''
	endif

	if l:beginning == '' || l:beginning =~ '\s$'
		return "\<Tab>"
	elseif (l:thisWord =~ '/')
		return "\<C-X>\<C-F>"
	else
		"return "\<C-X>\<C-O>"
		return "\<C-P>"
	endif
endfunction
imap <Tab> <C-R>=CleverTab()<CR>