form validation rule question

[eluser]TheFuzzy0ne[/eluser]

Code:

alpha_numeric      # letters and numbers
numeric            # numbers and characters to do with numbers (- and ., and perhaps +)?
is_numeric         # I think that's just synonym for the above, perhaps for the previous validation library? I don't know, but it's not in the reference. :)
integer            # numbers only (including - and perhaps +)?
is_natural         # 0 or more
is_natural_no_zero # 1 or more

Hope this helps.