From: dblack@...
Date: 2006-03-18T02:01:59+09:00
Subject: Re: Card tricks with Ruby

Hi --

On Sat, 18 Mar 2006, Stephen Waits wrote:

> Matthew Moss wrote:
>> 
> [snip]
>
> Well, it's definitely one of the (very) few things that has bothered me about 
> Ruby.  For example:
>
> A Rubyist might argue that this is more error prone:
>
>    for(int i=0;i<10;i++)
>
> than this:
>
>    10.times
>
> Which is a valid argument, and the result is elegant.  And, we see stuff like 
> this throughout Ruby.  As Why's guide says often, read the code aloud.
>
> So yes, .. vs ... really bugs me.  While they are convenient operators, I 
> also see them as too error prone to fit in Ruby.
>
> As an earlier mentioned example, when I've taught Ruby, I always feel like I 
> have to wave the red flags when I talk about ranges.
>
>> Unit testing could catch some errors, but I do agree if something
>> reasonably simple could replace it syntax-wise, it might be a tad
>> better.  What that something simple is, I don't know...  The simplest
>> solution would be to use mathematical notation, but that would be a
>> pita for the compiler to parse:   [0..x)
>
> Yah, [x..y], [x..y), (x..y], (x..y) would be sweetness.  It's slightly less 
> error-prone IMO since it's following a common (math) notation. Still, maybe 
> not perfect.

Can you really stand to look at that?  It gives me the same feeling as
putting my shoes on the wrong feet :-)

I'm not sure what it is about the range operators that bothers you.
Are you finding it hard to remember which is which?  My way of
remembering is: every range is the same width, in relation to the
operators.  Since the ... operator is wider, the end-point gets pushed
outside the range:

         v  v
         a..b
         a...b
         ^  ^

So b is off the map in the second one.  This is of course a schematic
way to view it (not proportional to the contents of the range), but I
found it helpful and maybe you will.


David

-- 
David A. Black (dblack@wobblini.net)
Ruby Power and Light, LLC (http://www.rubypowerandlight.com)

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