From: Simon Strandgaard <qj5nd7l02@...>
Date: 2003-11-17T10:23:33+09:00
Subject: Re: to_i

On Mon, 10 Nov 2003 17:44:36 +0100, Robert Klemme wrote:

> 
> "Artur Merke" <merke@ls1.cs.uni-dortmund.de> schrieb im Newsbeitrag
> news:Pine.LNX.4.33.0311101726040.17966-100000@as0203.cs.uni-dortmund.de...
[snip] 
> Why doesn't "hello".to_i deliver a nil as a return value, which can
> clearly be recognized as a conversion failure?
> 
>     IMHO this is a struggle between convenience and cleanness.  I guess
> Matz decided for convenience in this case, maybe because in most cases
> using 0 is ok.  If you want to do correct input checking you do
> /^[+-]?\d+$/ =~ foo anyway.


Something like this:


server> expand -t2 c.rb
def atoi(str)
  return str.to_i if /^\d+$/ =~ str
  raise "Cannot convert"
end

p atoi("42")    #-> 42
#p atoi("i18n")  #-> exception
#p atoi("0.42")  #-> exception
server>