(read1): Accept `single space' syntax like (? x).

diff --git a/src/lread.c b/src/lread.c
index 071bf67901513e64b29a8811b6ee5b78355fd850..70f0a3f2f9bc20fe5eeddecdc138e3ac88d009d0 100644 (file)
--- a/src/lread.c
+++ b/src/lread.c
@@ -2258,6 +2258,13 @@ read1 (readcharfun, pch, first_in_list)
        if (c < 0)
          end_of_file_error ();
 
+       /* Accept `single space' syntax like (list ? x) where the
+          whitespace character is SPC or TAB.
+          Other literal whitespace like NL, CR, and FF are not accepted,
+          as there are well-established escape sequences for these.  */
+       if (c == ' ' || c == '\t')
+         return make_number (c);
+
        if (c == '\\')
          c = read_escape (readcharfun, 0, &discard);
        else if (BASE_LEADING_CODE_P (c))