New experimental variable read-integer-overflow-as-float.

Following a suggestion by Eli Zaretskii (Bug#30408#46).
* etc/NEWS: Mention it.
* src/lread.c (syms_of_lread): Add it.
(read1): Treat out-of-range integers as floats if
read-integer-overflow-as-float is non-nil.

1 files changed, 10 insertions, 1 deletions

diff --git a/src/lread.c b/src/lread.c
index a774524ee43..8fb61f56338 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -3502,7 +3502,9 @@ read1 (Lisp_Object readcharfun, int *pch, bool first_in_list)
 
         if (!quoted && !uninterned_symbol)
           {
-            Lisp_Object result = string_to_number (read_buffer, 10, 0);
+            int flags = (read_integer_overflow_as_float
+                         ? S2N_OVERFLOW_TO_FLOAT : 0);
+            Lisp_Object result = string_to_number (read_buffer, 10, flags);
             if (! NILP (result))
               return unbind_to (count, result);
           }
@@ -4830,6 +4832,13 @@ were read in.  */);
                doc: /* Non-nil means read recursive structures using #N= and #N# syntax.  */);
   Vread_circle = Qt;
 
+  DEFVAR_BOOL ("read-integer-overflow-as-float",
+               read_integer_overflow_as_float,
+               doc: /* Non-nil means `read' quietly treats an out-of-range integer as floating point.
+Nil (the default) means signal an overflow unless the integer ends in `.'.
+This variable is experimental; email 30408@debbugs.gnu.org if you need it.  */);
+  read_integer_overflow_as_float = false;
+
   DEFVAR_LISP ("load-path", Vload_path,
                doc: /* List of directories to search for files to load.
 Each element is a string (directory file name) or nil (meaning