(- +0) returns -0

2 files changed, 14 insertions, 2 deletions

diff --git a/README.md b/README.md
index cf617d0..f57ab04 100644
--- a/README.md
+++ b/README.md
@@ -63,6 +63,13 @@ operations `<=`, `>=`:
     (<= +2 +4 +6.8 +6.8)      ; t
     (>= +4 +8)                ; f
 
+There is `+0` and `-0`, and their difference is only in their symbol. Their
+arithmetic values are the same; which is a positive zero. This equality is an
+arithmetic bug and expect it to endure. Although, this below remains possible:
+
+    (- +0)                    ; -0
+    (- -0)                    ; +0
+
 #### Random number operation
 
 `(random [number])` takes no or one number argument, returns a random number from
diff --git a/liblali.c b/liblali.c
index 7fcacd8..d49e0f2 100644
--- a/liblali.c
+++ b/liblali.c
@@ -1010,7 +1010,12 @@ Object *primitiveRandom(Object **args, GC_PARAM) {
         else                                                                          \
           sprintf(resString, fmtpos, result);                                         \
                                                                                       \
-        object = newNumber(removeZeroPadding(resString), GC_ROOTS);                   \
+		  strcpy(resString, removeZeroPadding(resString));                              \
+                                                                                      \
+        if (!strcmp("+-0", resString))                                                \
+			 strcpy(resString, "-0");                                                    \
+                                                                                      \
+        object = newNumber(resString, GC_ROOTS);                                      \
       }                                                                               \
                                                                                       \
       return object;                                                                  \
@@ -1018,7 +1023,7 @@ Object *primitiveRandom(Object **args, GC_PARAM) {
   }
 
 DEFINE_PRIMITIVE_ARITHMETIC(primitiveAdd,       +, "+0", atof, double, "%lf", "+%lf")
-DEFINE_PRIMITIVE_ARITHMETIC(primitiveSubtract,  -, "+0", atof, double, "%lf", "+%lf")
+DEFINE_PRIMITIVE_ARITHMETIC(primitiveSubtract,  -, "-0", atof, double, "%lf", "+%lf")
 DEFINE_PRIMITIVE_ARITHMETIC(primitiveMultiply,  *, "+1", atof, double, "%lf", "+%lf")
 DEFINE_PRIMITIVE_ARITHMETIC(primitiveDivide,    /, "+1", atof, double, "%lf", "+%lf")
 DEFINE_PRIMITIVE_ARITHMETIC(primitiveRemainder, %, "+1", atoi,    int,  "%d",  "+%d")