[idn] stringprep comment 1

["Soobok Lee" <lsb@postel.co.kr>]

 

In  Stringprep section 6.3,

 

" Newer stored string -- Suppose that an requesting application is using
 oldVersion and the stored string was created using a profile that uses
 newVersion. Because the requesting application passed through any
 unassigned code points, the user can query on stored strings that use
 code points in newVersion. No stored strings can have code points that
 are unassigned in newVersion, since that is illegal. In this case, the
 querying application has to enter the unassigned code points in the
 correct order, and has to use unassigned code points that would make it
 through both the mapping and the normalization steps."

 The old querying application using oldVersion stringprep  *cannot* predict

 

  1)    the correct order of combining sequences of newly assigned characters

 

  2)    the  normalized & casefolded form of newly assigned characters.

 

 This choices are often IME(platform) dependent and  enforcing such

   normalized character inputs are  beyond end users' choices and capabilities

   and also are out of control of independant application authors who are not

   inspired prophets.

 

  Non-Unicode legacy IMEs have been producing their own preferred character sequences

   for new scripts and their 1-1 mapping to new Unicode points may produce unnormalized outputs

   and they will be fed into old blind applications and make troubles and confusions and failtures.

 

 Therefore, the last sentence in the cited paragraph does not make sense, IMHO.

 

Soobok Lee