From: Justin Collins <collinsj@...>
Date: 2006-11-21T12:26:54+09:00
Subject: Re: Bug in ruby?

AliasX Neo wrote:
> Well, I've spent the last hour or so debugging one of the stupidest 
> errors I have encountered with Ruby.
>
>   
<snip>
> I debugged the application and put a mark on the first line to examine 
> it in the following code:
>
> [code]def parse(string, starting, ending)
>         length = starting.length
>         istart = string.index(starting) + length
>         iend = string.index(ending, istart)
>         return string.slice(istart, iend - istart)
>     end[/code]
>
> And the debugger said that length was an int with the value of 15. Guess 
> what still happened? Got the exact same error with the + operator on a 
> nil object. Except that completely contradicts the fact that it's not 
> nil but it's an int with the value of 15.
>   

+ is being called on string.index(starting) not length. I'd check to 
make sure you aren't getting nil from that:

def parse(string, starting, ending)
	p string.index(starting)
        istart = string.index(starting) + length
        iend = string.index(ending, istart)
        return string.slice(istart, iend - istart)
end

Hope that helps.

-Justin