[asdf-devel] ASDF and character encodings

[Daniel Herring]

This topic came up at the Boston Lisp meeting last night.  Here was my 
takeaway from the discussion.


ASDF does not need to support arbitrary encodings in system definition 
files.  UTF-8 is the simplest and most portable solution for non-ASCII 
characters in system definitions.

Thus ASDF can simply declare that all system definitions are read using 
UTF-8.  On systems where unicode support is not available, system 
definitions will be read as "extended ASCII", and the non-ASCII characters 
will simply print incorrectly.  Filenames should only be specified using 
ASCII characters to avoid portability issues.


Authors do need a way to support arbitrary encodings in other source 
files, but this should be restricted to cases where there is an actual 
need to use a non-UTF-8 character set.  Example use cases are 
locale-specific libraries, a toolchain that converts between character 
sets, or possibly a character-set-detection library.  Again, other 
character sets can be a major portability issue.


There are only a handful of libraries that use something other than ASCII 
or UTF-8.  These should be easy to fix, given approval from their authors.


Hopefully that's an accurate record of the general consensus and this 
writeup will be helpful to others in some way.

- Daniel