From: Mr Magpie <gazmcgheesubs@...>
Date: 2007-11-27T13:19:22+09:00
Subject: Re: FEATURE SUGGESTION: Accept default value for to_f and to_i

Yukihiro Matsumoto wrote:

> 
> I think Float(astring) that raises an exception for invalid string can
> do the work for you.
> 
> |It would allow even more succinct code when, say, reading in a
> |configuration value :
> |delay = configuration['delay'].to_f(DEFAULT_DELAY)
> 
> Try
> 
>   delay = Float(configuration['delay']) rescue DEFAULT_DELAY
> 
>               matz.

Thankyou for replying matz. I very much like the existing to_i and to_f 
methods approach of never throwing exceptions as they allow things like 
single line method chaining without fear of exceptions in the majority 
of cases where 0 is the desired default.

I'm merely suggesting that the error default value be customisable to 
distinguish bad input from valid input
eg. "0".to_i and "dds".to_i both return 0 and sometimes thats fine, but 
other times we want to know whether the input was a valid integer or 
not.

I believe exceptions are a performance drag, and these little functions 
are often called thousands of times in a loop for processing input, so 
I'd prefer to avoid a method that potentially causes exceptions. I think 
they would be among the more performance critical of all Ruby methods, 
which is why I'm suggesting these changes for the C based core rather 
than just making my own monkey patch.

Anyway, thanks for Ruby and replying to me.
-- 
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