At 12:41 PM +1100 12/31/07, Clifford Heath wrote:
>> Nits:
>> ... specification, design and implementation.
>> design,
>
> Why is this correct (a comma before "and"), when the following
> isn't? Is it because it's a list?
>
>> ... so evolution is costly, and the database ...
>> costly

Kind of. The serial comma is used in cases where there are three
or more items in a list, as:

A, B, or C
D, E, and F

Tom Christiansen, of Perl fame, likes this egregious example
as a way to show the perils of leaving out this comma:

I'd like to thank my parents, God and Mother Teresa.


The second case, in contrast, has the structure:

A, so B and C.

If it had the structure

A, so B, C, and D.

a comma would be appropriate (but breaking up the sentence
might be a better solution :-).

-r


P.S. Although I've worked as a technical writer and editor,
my formal training in grammar and punctuation is a bit
spotty. Follow any advice at your own risk...
--
http://www.cfcl.com/rdm Rich Morin
http://www.cfcl.com/rdm/resume rdm@...
http://www.cfcl.com/rdm/weblog +1 650-873-7841

Technical editing and writing, programming, and web development