From: Philipp Meier <meier@...>
Date: 2002-08-01T21:14:24+09:00
Subject: Re: Unicode in Ruby now?


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On Thu, Aug 01, 2002 at 07:53:07PM +0900, Curt Sampson wrote:
> On Thu, 1 Aug 2002, Tobias Peters wrote:
>=20
> > ...
> > We also need rules how to combine strings with different encoding then.
> > concatenating two strings encoded in koi8-r and iso-8859-1, respectivel=
y,
> > may only be possible when the result is encoded in some unicode
> > representation.
>=20
> Yeah. This is getting into complex nightmare city. That's why I'd prefer
> to have the basic system just work completely in Unicode. One could have
> a separate character system (character and string classes, byte-stream
> to char converters, etc.) to work with this tagged format if one wished.

Can't we follow an approach like ruby or java handles numbers? It's
naturally possible to add a floating point number and an integer. The
result is a floating point. I will sketch some ideas:

class String
  alias :+ :__+

  def + (other)
    if other.is_a? self.class
      self.__+(other)
    else
      self +=3D convert(other)
    end
  end
end

class ISO88591 < String=20
  def convert_from(other)
    if other.is_a? ASCII
      return other
    elsif other.is_a? UTF8
      return from_utf8
    else
      convert_from(UTF8.convert_from(other))
    end
  end

  def from_utf8()
    ...
  end

  def to_utf8()
    ...
  end
   =20
end

class UTF8 < String
  def convert_from(other)
    other.to_utf8
  end
end

The convert method can of course try to delegate everything to a UTF8
class, so that ascii -> iso-8859-1 will  result in ascii -> utf8 ->
iso8859-1. That means when introducing a new encoding one must only
provide a method to convert from / to utf8.

-billy.

--=20
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