(read1): Handle infinities, NaN and -0.0 specially.

(isfloat_string): Accept e+INF and e+NAN as exponents.

diff --git a/src/lread.c b/src/lread.c
index ef46e5f6a34f31984a2b21a5578f1acd839c30a0..ec72ded41ba42089c258b46a77f39bf114dc1b34 100644 (file)
--- a/src/lread.c
+++ b/src/lread.c
@@ -1907,7 +1907,23 @@ read1 (readcharfun, pch, first_in_list)
              }
 #ifdef LISP_FLOAT_TYPE
            if (isfloat_string (read_buffer))
-             return make_float (atof (read_buffer));
+             {
+               double value = atof (read_buffer);
+               if (read_buffer[0] == '-' && value == 0.0)
+                 value *= -1.0;
+               /* The only way this can be true, after isfloat_string
+                  returns 1, is if the input ends in e+INF or e+NaN.  */
+               if (p[-1] == 'F' || p[-1] == 'N')
+                 {
+                   if (p[-1] == 'N')
+                     value = 0.0 / 0.0;
+                   else if (read_buffer[0] == '-')
+                     value = -1.0e999;
+                   else
+                     value = 1.0e999;
+                 }
+               return make_float (value);
+             }
 #endif
          }
 
@@ -1968,6 +1984,17 @@ isfloat_string (cp)
       while (*cp >= '0' && *cp <= '9')
        cp++;
     }
+  else if (cp[-1] == '+' && cp[0] == 'I' && cp[1] == 'N' && cp[2] == 'F')
+    {
+      state |= EXP_INT;
+      cp += 3;
+    }
+  else if (cp[-1] == '+' && cp[0] == 'N' && cp[1] == 'a' && cp[2] == 'N')
+    {
+      state |= EXP_INT;
+      cp += 3;
+    }
+
   return (((*cp == 0) || (*cp == ' ') || (*cp == '\t') || (*cp == '\n') || (*cp == '\r') || (*cp == '\f'))
          && (state == (LEAD_INT|DOT_CHAR|TRAIL_INT)
              || state == (DOT_CHAR|TRAIL_INT)