From: Robert Klemme <bob.news@...>
Date: 2004-09-14T19:40:04+09:00
Subject: Re: Catching undefined global variable errors


"gabriele renzi" <rff_rff@remove-yahoo.it> schrieb im Newsbeitrag
news:4146C099.3070601@remove-yahoo.it...
> George Moschovitis ha scritto:
>
> >  I expected that the interpreter
> > would raise an Exception (undefined global or something) for
> > this code.
>
> well, the variable is defined, just defined badly :)
> for what relates to hashes, You can use an hash like this:
>  >> a=Hash.new { raise 'no such key' }
> => {}
>  >> a['key']
> RuntimeError: no such key
>          from (irb):1
>          from (irb):1:in `call'
>          from (irb):2:in `default'
>          from (irb):2:in `[]'
>          from (irb):2
>
> so that the error does not silently goes on..

You can use #fetch for that:

>> a={"here" => "there"}
=> {"here"=>"there"}
>> a.fetch "here"
=> "there"
>> a.fetch "not there"
IndexError: key not found
        from (irb):7:in `fetch'
        from (irb):7

Regards

    robert