/^\.(\w+).+$\^\t+\.\w+\W+(\w+)/m

##</code><code>##

/(?:^|\n)\.(\w+).+\n\t+\.\w+\W+(\w+)/m

##</code><code>##

/(?:^|\n)       # Start matching either at the start of the string
                # or at a newline. The ?: part means, that
                # the parentheses I use don't get saved in $1
  \.(\w+).+\n   # match a line starting with a dot-word and some
                # more stuff
  \t+\.\w+      # The line after this must start with at least one
                # tab and then a dot-word
  \W+(\w+)      # and contain some other stuff as well ...
/mx