[Chicken-users] External representation of strings with non-printable characters

[Thomas Chust]

Hello,

I just came across this slightly strange behaviour of CHICKEN on a terminal:

$ csi
 ______ __     __        __
|      |  |--.|__|.----.|  |--.-----.-----.
|   ---|     ||  ||  __||    <|  -__|     |
|______|__|__||__||____||__|__|_____|__|__|
Version 2, Build 101 - macosx-unix-gnu-ppc - [ dload ]
(c)2000-2005 Felix L. Winkelmann
#;1> (define str (string #\nul #\x02 #\1))
#;2> (string->list str)
(#\nul #\x2 #\1)
#;3> str
"\\1"
#;4> (string->list "\\1")
(#\\ #\1)
#;5> (string->list "\x00\x021")
(#\nul #\x2 #\1)

Similar behaviour can also be seen if you apply string->symbol to the 
above string and write the symbol.

Although writing all sorts of special characters to the output port as 
themselves works fine for file ports, terminals may get confused by 
this. I think it would be nicer to output characters <32 and >128 as 
hexadecimal or octal escape sequences, at least on a terminal port.

cu,
Thomas Chust