character matching

["John J" <g_001@hotmail.com>]

To develop a program that counts words and sentences I'm trying to write
some code that will recognise a word due to it being a series of
alphanumeric characters terminated by one or more of a space, comma,
fullstop, colon, exclamation mark or question mark. I'm going to use a case
to match the condition then perform an advance on a wordcounter.

I also need to include a case match that will recognise sentences by being a
sequence of words terminated by one or more of full stop, exclamation mark,
question mark or colon. The code also needs to be able to accept that there
maybe spaces between the last word of the sentence and the terminating stop
ie. "hope this works  !". I'm not sure on how to match these conditions and
would greatly appreciate some assistance. My skeletion code is as follows:

case input(Character) is
    when ???????       -- find word
        Word_Count:= Word_Count + 1.0;
    when ??????        -- find sentence
        Sentence_Count:= Sentence_Count + 1.0;
end case;

Thanks for any help