Re: Custom types and default values

On 31 May 2004, John Belmonte said:
> My question wasn't if strings would be required, but rather if you would 
> still be promoting the use of non-strings.  Anyway, I think I've got the 
> answer :-).

Sorry, forgot to answer that explicitly.  To me,

  add_option("-n", type="int", default=37)

is far preferable to

  add_option("-n", type="int", default="37")

.  So for built-in types, *my* preferred way of working will continue to
be "supply a post-type-conversion value".  But you're free to supply a
string if you like.

For custom types, it's up to the developer, but there are at least two
clear advantages to providing a pre-type-conversion string:

  * better help ("%default" expands to "5m", not "300")
  * some sanity-checking of the developer's default

> I can't argue that it's not an application bug.  Having everything come 
> to a halt when you've got some inconsistency in your program is 
> considered a desirable trait by many programmers.

I totally agree.  If you want that trait with Optik 1.5, then you are
quite free to write

  add_option("-n", type="constrained_int", default="51")

and then watch things blow up when your type-checker for constrained_int
rejects "51" as out of range.  With Optik 1.4.1, you don't have that
option.

        Greg
-- 
Greg Ward <[email protected]>                         http://www.gerg.ca/
Never try to outstubborn a cat.


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