fixes #693

doc/sets_fragment.txt

@@ -29,7 +29,6 @@ operation             meaning
 ``e in A``            set membership (A contains element e)
 ``e notin A``         A does not contain element e
 ``contains(A, e)``    A contains element e
-``A -+- B``           symmetric set difference (= (A - B) + (B - A))
 ``card(A)``           the cardinality of A (number of elements in A)
 ``incl(A, elem)``     same as ``A = A + {elem}``
 ``excl(A, elem)``     same as ``A = A - {elem}``

lib/system.nim

@@ -842,9 +842,6 @@ proc `+` *[T](x, y: set[T]): set[T] {.magic: "PlusSet", noSideEffect.}
   ## This operator computes the union of two sets.
 proc `-` *[T](x, y: set[T]): set[T] {.magic: "MinusSet", noSideEffect.}
   ## This operator computes the difference of two sets.
-proc `-+-` *[T](x, y: set[T]): set[T] {.magic: "SymDiffSet", noSideEffect.}
-  ## computes the symmetric set difference. This is the same as
-  ## ``(A - B) + (B - A)``, but more efficient.
 
 proc contains*[T](x: set[T], y: T): bool {.magic: "InSet", noSideEffect.}
   ## One should overload this proc if one wants to overload the ``in`` operator.

web/news.txt

@@ -3,7 +3,7 @@ News
 ====
 
 ..
-  2014-10-21 Version 0.10.0 released
+  2014-10-21 Version 0.10.2 released
   ==================================
 
   Changes affecting backwards compatibility
@@ -26,6 +26,8 @@ News
     fails to match.
   - The re module returns ``nil`` instead of ``""`` when an optional capture
     fails to match.
+  - The "symmetric set difference" operator (``-+-``) never worked and has been
+    removed.
 
   Language Additions
   ------------------