[UKLUG] Re: LPM: unless ($line =~ /^#/)

[Rich Bowen]

> > Unless may be great for throw-away programs, where you're trying to code
> > quick, but as you can always negate the test in your condition, it's
> > normally easier to maintain when you always use 'if'.
> >
> > Besides, it's fewer keystrokes to type:
> >
> >         if ($line !~ /^#/)
> >
> > vs.
> >         unless ($line =~ /^#/)
> >
> > -----
> > Joe Hourcle
> 
> If the boolean expression is that simple, you're probably right.  If the
> if clause is more complex, then I think the unless is often more
> readable:
> 
>         if (not($hairy_compound_boolean_expression)) {
> 
> vs.
> 
>         unless ($hairy_compound_boolean_expression) {
> 
> That removes a set of parentheses and should still be readable.
> Assuming there's no else at the end of it though, because the else would
> give a better opportunity to clarify.

Particularly when you are doing statement modifiers, unless leads to
very consise and readable code.

next unless $line;

Which would be cumbersome using if.
-- 
Rich Bowen --  Director of Web Application Development
http://www.cre8tivegroup.com/  --  rich at cre8tivegroup.com
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