cl-format: ~$ wasn't handling negative numbers correctly

refs #40

src/clojure/contrib/pprint/cl-format.clj

@@ -759,7 +759,7 @@ Note this should only be used for the last one in the sequence"
         d (:d params) ; digits after the decimal
         n (:n params) ; minimum digits before the decimal
         w (:w params) ; minimum field width
-        add-sign (and (:at params) (not (neg? arg)))
+        add-sign (or (:at params) (neg? arg))
         [rounded-mantissa scaled-exp _] (round-str mantissa exp d nil)
         #^String fixed-repr (get-fixed rounded-mantissa scaled-exp d)
         full-repr (str (apply str (repeat (- n (.indexOf fixed-repr (int \.))) \0)) fixed-repr)

src/clojure/contrib/test_contrib/pprint/cl_format.clj

@@ -176,7 +176,22 @@
   (cl-format nil "~3,5,14@$" 22.375) "    +00022.375"
   (cl-format nil "~3,5,14@$" 22.375) "    +00022.375"
   (cl-format nil "~3,5,14@:$" 22.375) "+    00022.375"
-  (cl-format nil "~3,,14@:$" 0.375) "+        0.375")
+  (cl-format nil "~3,,14@:$" 0.375) "+        0.375"
+  (cl-format nil "~1,1$" -12.0) "-12.0"
+  (cl-format nil "~1,1$" 12.0) "12.0"
+  (cl-format nil "~1,1$" 12.0) "12.0"
+  (cl-format nil "~1,1@$" 12.0) "+12.0"
+  (cl-format nil "~1,1,8,' @:$" 12.0) "+   12.0"
+  (cl-format nil "~1,1,8,' @$" 12.0) "   +12.0"
+  (cl-format nil "~1,1,8,' :$" 12.0) "    12.0"
+  (cl-format nil "~1,1,8,' $" 12.0) "    12.0"
+  (cl-format nil "~1,1,8,' @:$" -12.0) "-   12.0"
+  (cl-format nil "~1,1,8,' @$" -12.0) "   -12.0"
+  (cl-format nil "~1,1,8,' :$" -12.0) "-   12.0"
+  (cl-format nil "~1,1,8,' $" -12.0) "   -12.0")
+
+(simple-tests f-tests
+  (cl-format nil "~,1f" -12.0) "-12.0")
 
 (simple-tests ampersand-tests
   (cl-format nil "The quick brown ~a jumped over ~d lazy dogs" 'elephant 5)