From: matt@... (matt neuburg)
Date: 2009-04-22T04:55:09+09:00
Subject: Re: Is there a better way to do this?

Paul Mckibbin <pmckibbin@gmail.com> wrote:

> I recently had code which needed to work with the same structure twice,
> once using the . nomenclature and once with an index into a hash.
> i.e. in one case I had
> 
> entries=@log.entry
> 
> which I would interrogate with:
> 
> entries.timings.connect.first_byte
> 
> or alternatively
> 
> entries.XmlSimple(in_file)
> 
> which I would interrogate with:
> 
> entries['timings']['connect']['first_byte'].
> 
> Rather than write two blocks for code, one for the in-memory, I decided
> to override the base structure that XmlSimple used, but I found out that
> it was Hash. So the following was what I came up with:
> 
>   class Hash
>     def method_missing(sym,*args,&blk)
>      return self[sym] if self.keys.include?(sym)
>      return self[sym.to_s] if self.keys.include?(sym.to_s)
>      super
>     end
>   end
> 
> which works for me, but I was wondering if there is a better way to do
> this than calling self.keys.include? to determine if the key exists
> without triggering any unexpected side effects.

I would have thought that key? is the basic form here.

Also, just a thought, you might look at ostruct which plays off the very
same impulse you're having (i.e. to talk to hash as if it were a struct
with accessors). The code might give you some ideas...

m.

-- 
matt neuburg, phd = matt@tidbits.com, http://www.tidbits.com/matt/
Leopard - http://www.takecontrolbooks.com/leopard-customizing.html
AppleScript - http://www.amazon.com/gp/product/0596102119
Read TidBITS! It's free and smart. http://www.tidbits.com