Why can't I use "or" here?
in [Ruby]
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From: David A. Black on 1 Jan 2010 06:20 Hi -- On Thu, 31 Dec 2009, Albert Schlef wrote: > Well. it turns out there aren't that many ways in ruby. > > I originally tried to do the following: > > some_func(ARGV[0] or raise "You must provide an argument") > > I wish it worked. But it doesn't. So I changed it to: > > some_func(ARGV[0] || raise "You must provide an argument") > > It still didn't work. So finally I did: > > some_func(ARGV[0] || (raise "You must provide an argument")) > > It works. But, I must say, it isn't as beautiful as my original plan. It > doesn't read as English. It's not supposed to; it's supposed to read as Ruby :-) I wouldn't make too much of the English-likeness. I think of it more as an emergent thing than as a style guideline. David -- David A. Black Senior Developer, Cyrus Innovation Inc. THE COMPLEAT RUBYIST, Ruby training with Black/Brown/McAnally! January 22-23, Tampa, Florida Info and registration at http://www.thecompleatrubyist.com
From: Phillip Gawlowski on 1 Jan 2010 06:25 On 01.01.2010 12:15, David A. Black wrote: > I wouldn't worry about that idiom ceasing to work :-) In open source software (or Free Software), I *do* worry about API stability, or rather compatibility of version X to version Y. I've been burned by Linux kernel changes far too often to *not* worry. :( Mind, I'm not averse to change, even change that sheds weight and thus breaks backwards compatibility, but I prefer it to be in a major release, rather than a minor version. Very different issue from the OP, though. -- Phillip Gawlowski
From: David A. Black on 1 Jan 2010 06:29 Hi -- On Fri, 1 Jan 2010, Phillip Gawlowski wrote: > On 01.01.2010 12:15, David A. Black wrote: > >> I wouldn't worry about that idiom ceasing to work :-) > > In open source software (or Free Software), I *do* worry about API stability, > or rather compatibility of version X to version Y. So do I, but I think we're safe on this particular one. That's all I mean. David -- David A. Black Senior Developer, Cyrus Innovation Inc. THE COMPLEAT RUBYIST, Ruby training with Black/Brown/McAnally! January 22-23, Tampa, Florida Info and registration at http://www.thecompleatrubyist.com
From: botp on 1 Jan 2010 07:30
On Thu, Dec 31, 2009 at 3:13 PM, Jeff Peng <jeffpeng(a)netzero.net> wrote: > I know Perl, but I'm still surprised. > > # perl -le 'print undef or 4' > > # perl -le 'print(undef or 4)' > 4 do not be surprise, ruby opted for the former case since it is more common, and therefore has relegated the "or/and" ops w very low precedence level (and ergo different fr their sibling ops "||/&&") in other words, if you see a method like >> puts 1,2 or 4 1 2 => 4 it actually means >> puts( 1,2) or 4 1 2 => 4 and if you write a statement like >> puts( 1,2 or 4) ruby will err for you but friendly enough to allow you to by (re)emphasizing... so maybe you meant >> puts( 1, (2 or 4)) best regards -botp |