>I think the root of the problem is that when editing in browser window or a
>file's contents in a FileList (?), pasting text terminated with cr into a
>text terminated with crlf, or crlf into cr, will leave the resulting text
>with "mixed" line termination.

Regardless of the LF conventions for external files, the fileIn after 
reading should be CR-terminated.  Inside a Squeak browser, there 
should be no LF at all, except perhaps in a literal string.  Inside 
of Squeak, all text is terminated with cr.

Does the SIF "standard" specify what kinds of line returns will be 
used?  If so, those should be used in EVERY platform.  If not, then 
does SIF specify that consistent line returns will be used?  If not, 
I suppose you should presume they contain arbitrary, that is, plural 
line feed conventions between lines, converting each upon reading to 
CR.  Of course, this creates a cross-platform nightmare in literal 
strings, particularly when a string intentionally contains line-ends. 
C'est la guerre.