bug#15033: [PATCH] Fix display of symbols containing backslashes

[Mark H Weaver]

David Kastrup <address@hidden> writes:

> Symbols printed with `#{...#}' notation need to double backslashes when
> displaying as they serve as escape characters when reading.  The
> behavior before this patch is clearly erroneous:
>
> GNU Guile 2.0.7
> [...]
> scheme@(guile-user)> (string->symbol "\\(")
> $1 = #{\\x28;}#
> scheme@(guile-user)> (symbol->string '#{\\x28;}#)
> $2 = "\\x28;"
> ---
>  libguile/print.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/libguile/print.c b/libguile/print.c
> index 50f5a3e..bb7fd84 100644
> --- a/libguile/print.c
> +++ b/libguile/print.c
> @@ -448,7 +448,8 @@ print_extended_symbol (SCM sym, SCM port)
>                                              SUBSEQUENT_IDENTIFIER_MASK
>                                              | UC_CATEGORY_MASK_Zs))
>          {
> -          if (!display_character (c, port, strategy))
> +          if (!display_character (c, port, strategy)
> +           || (c == '\\' && !display_character (c, port, strategy)))
>              scm_encoding_error ("print_extended_symbol", errno,
>                                  "cannot convert to output locale",
>                                  port, SCM_MAKE_CHAR (c));

Applied in b4a099883d20d7852c95acf07ab6cbc56bce18c4.

     Thanks!
       Mark