Index: Objects/stringlib/formatter.h
===================================================================
--- Objects/stringlib/formatter.h	(revision 70708)
+++ Objects/stringlib/formatter.h	(working copy)
@@ -262,6 +262,8 @@
 		   Py_ssize_t n_prefix, Py_ssize_t n_digits,
 		   const InternalFormatSpec *format)
 {
+    int no_sign_allowed = actual_sign == 'n' || actual_sign == 'i';
+        
     spec->n_lpadding = 0;
     spec->n_prefix = 0;
     spec->n_spadding = 0;
@@ -291,7 +293,7 @@
     */
 
     /* compute the various parts we're going to write */
-    if (format->sign == '+') {
+    if (format->sign == '+' && !no_sign_allowed) {
         /* always put a + or - */
         spec->n_lsign = 1;
         spec->lsign = (actual_sign == '-' ? '-' : '+');
@@ -369,9 +371,11 @@
         STRINGLIB_FILL(p_buf, fill_char, spec->n_lpadding);
         p_buf += spec->n_lpadding;
     }
+
     if (spec->n_lsign == 1) {
         *p_buf++ = spec->lsign;
     }
+
     if (spec->n_prefix) {
 	memmove(p_buf,
 		prefix,
@@ -781,7 +785,7 @@
     if (x == -1.0 && PyErr_Occurred())
         goto done;
 
-    if (type == '%') {
+    if (type == '%' && Py_IS_FINITE(x)) {
         type = 'f';
         x *= 100;
         trailing = "%";
@@ -792,21 +796,28 @@
     if (type == 'f' && fabs(x) >= 1e50)
         type = 'g';
 
-    /* cast "type", because if we're in unicode we need to pass a
-       8-bit char.  this is safe, because we've restricted what "type"
-       can be */
-    PyOS_snprintf(fmt, sizeof(fmt), "%%.%" PY_FORMAT_SIZE_T "d%c", precision,
-		  (char)type);
+    if (Py_IS_NAN(x))
+            strcpy(charbuf, "nan");
+    else if (Py_IS_INFINITY(x)) {
+	if (x > 0)
+	    strcpy(charbuf, "inf");
+	else
+	    strcpy(charbuf, "-inf");
+    } else {
+	/* cast "type", because if we're in unicode we need to pass a 8-bit
+	   char.  this is safe, because we've restricted what "type" can be */
+	PyOS_snprintf(fmt, sizeof(fmt), "%%.%" PY_FORMAT_SIZE_T "d%c",
+		      precision, (char)type);
+            
+	/* do the actual formatting */
+	PyOS_ascii_formatd(charbuf, sizeof(charbuf), fmt, x);
+	
+	/* adding trailing to fmt with PyOS_snprintf doesn't work, not sure
+	   why.  we'll just concatentate it here, no harm done.  we know we
+	   can't have a buffer overflow from the fmt size analysis */
+	strcat(charbuf, trailing);
+    }
 
-    /* do the actual formatting */
-    PyOS_ascii_formatd(charbuf, sizeof(charbuf), fmt, x);
-
-    /* adding trailing to fmt with PyOS_snprintf doesn't work, not
-       sure why.  we'll just concatentate it here, no harm done.  we
-       know we can't have a buffer overflow from the fmt size
-       analysis */
-    strcat(charbuf, trailing);
-
     /* rather than duplicate the code for snprintf for both unicode
        and 8 bit strings, we just use the 8 bit version and then
        convert to unicode in a separate code path.  that's probably
@@ -838,7 +849,8 @@
 
     /* Fill in the non-digit parts (padding, sign, etc.) */
     fill_non_digits(STRINGLIB_STR(result), &spec, NULL, n_digits,
-		    format->fill_char == '\0' ? ' ' : format->fill_char);
+		    (format->fill_char == '\0' || !Py_IS_FINITE(x))
+                    ? ' ' : format->fill_char);
 
     /* fill in the digit parts */
     memmove(STRINGLIB_STR(result) +