From: Charlie Bowman <charlie@...>
Date: 2006-04-12T03:37:32+09:00
Subject: Re: Style question: if !x vs. unless x

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I never like to start a line off with unless.  It just looks confusing
to me.

On Wed, 2006-04-12 at 03:21 +0900, Justin Collins wrote:

> David Brady wrote:
> > Hi all,
> >
> > One of the coolest things for me about learning ruby is that it's the 
> > first language I've learned in a decade where I actually had to learn 
> > a new language.  Once you know C/C++, you can pick up Java, PHP, perl, 
> > Python, and even VB without really having to learn new grammar... you 
> > just learn where the braces and dollar signs go.  One of the joys of 
> > ruby is that when I find myself using a klunky grammar construct, 
> > there is often an elegant solution if I will just surrender my C++ 
> > thinking style.
> >
> > That paragraph could spark a thread of its own, but in this case, its 
> > lead-up for a simpler question.  Which do you find more readable:
> >
> > # this version
> > if !correct
> >  handle_error
> >  do_some_other_thing
> > end
> >
> > # or this version
> > unless correct
> >  handle_error
> >  do_some_other_thing
> > end
> >
> > When dealing with single-lines, I find the inverted construct to be 
> > MUCH more readable:
> >
> > handle_error unless correct
> >
> > but when I have to make a block, my C++ instincts really prefer the 
> > "if !" version.
> >
> > I'm just throwing this out here... what do you prefer, and why?  Do 
> > you find the "unless x" construct as (or more) readable than the "if 
> > !x" construct? 
> <snip>
> >
> >
> > -dB
> >
> 
> Personally, I've been going with the 'unless' statement much more often, 
> but it depends on the context. I generally use "unless" when I think the 
> conditional is unusual and I normally would do what's in the block:
> 
> unless something_is_weird
>     do stuff
> end
> 
> But that's just because I'm thinking about the normal meaning of 'unless'.
> I also use the 'word' versions of logical operators to make things more 
> clear for myself:
> 
> if not correct
>     #do something
> end
> 
> is very easy to follow. Just beware of the lower precedence of those 
> constructs.
> This could be just me, though.
> 
> -Justin
> 
> 



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