* arith.c (int_flo): If sprintf produces something

that doesn't begin with a digit, it's most likely NaN or Inf.
We can turn that into an exception.

* stream.c (vformat): If sprintf produces a non-number,
turn it into the printed representation #<bad-float>.

3 files changed, 29 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 9ca30cf7..7da801c8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,14 @@
 2012-03-22  Kaz Kylheku  <kaz@kylheku.com>
 
+	* arith.c (int_flo): If sprintf produces something
+	that doesn't begin with a digit, it's most likely NaN or Inf.
+	We can turn that into an exception.
+
+	* stream.c (vformat): If sprintf produces a non-number,
+	turn it into the printed representation #<bad-float>.
+
+2012-03-22  Kaz Kylheku  <kaz@kylheku.com>
+
 	* arith.c (to_float): New static function.
 	(divi): Uses to_float.
 	(zerop, gt, lt, ge, le, expt): Floating support.
diff --git a/arith.c b/arith.c
index c98d0531..6bb82efd 100644
--- a/arith.c
+++ b/arith.c
@@ -39,6 +39,7 @@
 #include <wchar.h>
 #include <limits.h>
 #include <math.h>
+#include <ctype.h>
 #include "config.h"
 #include "lib.h"
 #include "unwind.h"
@@ -1315,6 +1316,11 @@ val int_flo(val f)
 
     sprintf(text, "%.64g", d);
 
+    if (!isdigit(text[0]))
+      uw_throwf(error_s,
+                lit("int-flo: cannot convert #<bad-float> to integer"),
+                nao);
+
     have_exp = (strchr(text, 'e') != 0);
     have_point = (strchr(text, '.') != 0);
 
diff --git a/stream.c b/stream.c
index 6110e1d6..6761afd8 100644
--- a/stream.c
+++ b/stream.c
@@ -32,6 +32,7 @@
 #include <assert.h>
 #include <setjmp.h>
 #include <errno.h>
+#include <ctype.h>
 #include <wchar.h>
 #include <unistd.h>
 #include "config.h"
@@ -1147,6 +1148,12 @@ val vformat(val stream, val fmtstr, va_list vl)
               sprintf(num_buf, "%.*e", precision, n);
             else
               sprintf(num_buf, "%.*f", precision, n);
+            if (!isdigit(num_buf[0])) {
+              if (!vformat_str(stream, lit("#<bad-float>"),
+                               width, left, precision))
+                return nil;
+              continue;
+            }
             precision = 0;
             goto output_num;
           }
@@ -1170,6 +1177,13 @@ val vformat(val stream, val fmtstr, va_list vl)
           case FLNUM:
             sprintf(num_buf, "%g", obj->fl.n);
 
+            if (!isdigit(num_buf[0])) {
+              if (!vformat_str(stream, lit("#<bad-float>"),
+                               width, left, precision))
+                return nil;
+              continue;
+            }
+
             if (!precision) {
               if (!strpbrk(num_buf, "e."))
                 strcat(num_buf, ".0");