From: James Gray <james@...>
Date: 2009-08-12T23:35:46+09:00
Subject: Re: 1.9 String and M17N documentation

On Aug 12, 2009, at 5:13 AM, Brian Candler wrote:

> James Gray wrote:
>> * Just FYI, you ask the following about Regexp::FIXEDENCODING:
>>
>> # FIXME: What is the purpose of this flag?
>>
>> I do try to explain that under Regexp Encodings in this article, if
>> you are interested:
>>
>> http://blog.grayproductions.net/articles/miscellaneous_m17n_details
>
> "A fixed_encoding?() Regexp is one that will raise an
> Encoding::CompatibilityError if matched against any String that  
> contains
> a different Encoding from the Regexp itself."
>
> I think that's not exactly correct:
>
> $ irb19 --simple-prompt
>>> re = /gro/u
> => /gro/
>>> re.encoding
> => #<Encoding:UTF-8>
>>> re.fixed_encoding?
> => true
>>> str = "gro".force_encoding("ISO-8859-1")
> => "gro"
>>> re =~ str
> => 0
>
> AFAICS, it will only raise an error if the matched string is of a
> different encoding *and* is not ascii_only?
>
>>> str = "gro\xdf".force_encoding("ISO-8859-1")
> => "gro�"
>>> re =~ str
> Encoding::CompatibilityError: incompatible encoding regexp match  
> (UTF-8
> regexp with ISO-8859-1 string)

Thanks for the correction.  I've updated the article you quoted with a  
correction.

James Edward Gray II