bug#31864: Hex-escaped r6rs symbols are not read correctly

[Göran Weinholt]

Hello schemers!

R6RS specifies an inline hex escape syntax for symbols. These do not
work in Guile 2.2.3:

scheme@(guile-user)> (read-enable 'r6rs-hex-escapes)
$1 = (square-brackets r6rs-hex-escapes keywords #f positions)
scheme@(guile-user)> (symbol->string '\x7c;
)
$2 = "\\x7c"

I expected this to return "|".

While fixing this, perhaps it would also be possible to add recognition
of #!r6rs to set the appropriate per-port read options, similarly to how
#!fold-case is recognized? It would make it much easier to load R6RS
code in Guile.

Best Regards,

-- 
Göran Weinholt
Debian developer
73 de SA6CJK