From: Tom Sawyer <transami@...>
Date: 2002-07-11T17:58:34+09:00
Subject: Re: String#split converts string args to regexes -- ?

stepan,

i think you should read this:

> Imagine this...
> 
> There is a 16compat.rb file in ruby1.8 lib directory.  By requiring
> it, all language features that have been changed (not added) in 1.8
> assume 1.6 behaviour.  You could put a require 'compat16' in your
> script, and you would be sure that, if it ran under 1.6, it will run
> for you.  You could even set that system-wide to be sure (e.g. `ruby'
> is really a script containing `ruby -rcompat1.6') and require
> 'compat18' for new projects.  Most important, by doing so on the new
> project, whatever change will happen in ruby2.0 you already know your
> script will still run because compat18.rb in ruby2.0 will take care of
> it...
> 
> Just a thought.
> 
> Massimiliano

~transami


On Thu, 2002-07-11 at 02:30, Stepan Kasal wrote:
> Hallo,
> 
> > Quick reminder, for reference :-)
> > 
> >   sub/gsub
> > 
> >    (a) prohibit string pattern
> >    (b) string patterns as strings, without converting into regex.
> > 
> >   split
> > 
> >    (c) prohibit string pattern longer than 1.
> >    (d) string patterns as strings, without converting into regex.
> 
> > On Wed, 10 Jul 2002, Stepan Kasal wrote:
> > > So I vote for a-c, with an error message saying something like
> > > "use either Regexp.new(s) or Regexp.new(Regexp.quote(s)) to clarify"
> 
> On Wed, 10 Jul 2002 12:35:54 GMT, David Alan Black wrote:
> [...]
> > It's partly a matter of documentation stating that String#split takes
> > a string or a regex, without (anywhere I've seen) noting that the
> > string has to be only one character long or else has to follow regex
> > syntax (because it's really a regex).
> > 
> > I'm not sure what the disadvantage of allowing a string argument is.
> 
> The disadvantage is that people will often write "error[.]log", hoping
> that this will match the string "error.log".  The reason for writing this
> is not only the habit inherited from other languages, it may be simply
> a program which used to work in a previous version of Ruby (though it
> should not, according to the docs ;-).
> 
> How would you like if a review of a new version of Ruby said this:
> 
> 	We experienced non-complete backward compatibility with this
> 	version, at least.  Our old programs just stopped working, though
> 	no error message appeared.  We traced this down to a
> 	(mis-)behaviour of the split() function.   [...]
> 	We recommend reviewing all your programs carefully before upgrading
> 	Ruby, especially in a production environment.
> 
> I know, similar reasoning applies to my solution (a-c with an error message),
> at least to an extent, because the error is detected in runtime, so it may
> last some time till the surprise appears.  But I think crashing programs
> is better then changing the semantics of old programs in a weird way.
> 
> > It's not mandatory -- you can always use a regex (or even
> > Regexp.new(s) :-)  -- so allowing strings (without auto-conversion to
> > regex) doesn't take away any functionality.
> 
> I think that arguments like this one lead to non-elegant non-readable
> languages.
> 
> Stepan
> 
-- 
~transami

"They that can give up essential liberty to obtain a little
 temporary safety deserve neither liberty nor safety."
	-- Benjamin Franklin