Matching -- in a string

[peterhickman <peterhi@...>]

I am trying to do the following:

a = 'this line has a -- comment'
b = 'this line does not'

print(string.find(a,"--"))
print(string.find(b,"--"))

but in both cases the results are
1   0
1   0

how do I match "--" in a string?

--
Fear is Money