diff --git a/README.md b/README.md
index 404ee21..eba406e 100644
--- a/README.md
+++ b/README.md
@@ -27,7 +27,7 @@ requires "cppstl"
 
 ## Limitations
 
-``cppstl`` currently wraps :
+#### ``cppstl`` currently wraps :
 
 * ``std::string``
 * ``std::basic_string``
@@ -39,6 +39,26 @@ requires "cppstl"
   * ``std::unique_ptr``
   * ``std::shared_ptr``
 
+#### Avoid using wrapped STL objects in top-level Nim scope.
+  Most of the times it works on Nim 1.x but leads to both compile-time and runtime errors on 2.x.
+  So instantiate them in subroutines only to ensure portability between 1.x and 2.x.
+
+I.e this usecase is not recommended: 
+```
+when isMainModule:
+  var vec = initCppVector[int]()
+  vec.pushBack(20)
+```
+Use this one instead:
+```
+when isMainModule:
+  proc foo = 
+    var vec = initCppVector[int]()
+    vec.pushBack(20)
+  foo()
+```
+
+
 ## Contributions
 
 All contributions are welcome!
diff --git a/cppstl/std_string.nim b/cppstl/std_string.nim
index ae408d2..bc34685 100644
--- a/cppstl/std_string.nim
+++ b/cppstl/std_string.nim
@@ -24,7 +24,7 @@ proc initCppString*(s: cstring, n: csize_t): CppString {.constructor, importcpp:
 proc initCppString*(first, last: CppStrConstIterator): CppString {.constructor, importcpp: "std::string(@)".}
 
 # Modifiers
-proc `+=`*(self: var CppString, str: cstring) {.importcpp: "# += #".}
+proc `+=`*(self: var CppString, str: cstring) {.importcpp: "(# += #)".}
 
 proc append*(self: var CppString, str: cstring) {.importcpp: "append".}
 proc append*(self: var CppString, str: cstring, n: csize_t) {.importcpp: "append".}
@@ -70,6 +70,14 @@ proc compare*(self: CppString, pos, l: csize_t, str: cstring, subpos, subl: csiz
 # Converter: CppStrIterator -> StrConstIterator
 converter CppStrIteratorToStrConstIterator*(s: CppStrIterator): CppStrConstIterator {.importcpp: "#".}
 
+# Relational operators
+proc `==`*(a: CppString, b: CppString): bool {.importcpp: "(# == #)".}
+proc `!=`*(a: CppString, b: CppString): bool {.importcpp: "(# != #)".}
+proc `<`*(a: CppString, b: CppString): bool  {.importcpp: "(# < #)".}
+proc `<=`*(a: CppString, b: CppString): bool {.importcpp: "(# <= #)".}
+proc `>`*(a: CppString, b: CppString): bool  {.importcpp: "(# > #)".}
+proc `>=`*(a: CppString, b: CppString): bool {.importcpp: "(# >= #)".}
+
 {.pop.}
 
 {.push inline.}
diff --git a/tests/tcomplex.nim b/tests/tcomplex.nim
index b98c029..4555e4a 100644
--- a/tests/tcomplex.nim
+++ b/tests/tcomplex.nim
@@ -4,6 +4,7 @@ import complex
 import std/math
 import cppstl/std_complex
 
+
 proc main() =
   suite "CppComplex":
     test "constructors":
@@ -28,6 +29,7 @@ proc main() =
           refres = refa + refb
           res = a + b
         check almostEqual(refres, toComplex(res))
+
       block:
         var
           a = initCppComplex[float64](141.571, 124.412)
@@ -94,3 +96,4 @@ proc main() =
 
 when isMainModule:
   main()
+
diff --git a/tests/tpair.nim b/tests/tpair.nim
index 3c73394..4496974 100644
--- a/tests/tpair.nim
+++ b/tests/tpair.nim
@@ -116,5 +116,7 @@ proc main() =
       check tup == (first: f, second: s)
       check makePair(tup) == pair
 
+
 when isMainModule:
   main()
+
diff --git a/tests/tstring.nim b/tests/tstring.nim
index ee94cac..ad433d9 100644
--- a/tests/tstring.nim
+++ b/tests/tstring.nim
@@ -2,6 +2,7 @@
 import unittest
 import cppstl/std_string
 
+
 proc main() =
   suite "CppString":
     test "constructors and iterators":
@@ -416,5 +417,7 @@ proc main() =
         c = 'b'
       check s1.toString == "bbbbbbbbb"
 
+
 when isMainModule:
   main()
+
diff --git a/tests/tvector.nim b/tests/tvector.nim
index ba13d2d..b3fdd34 100644
--- a/tests/tvector.nim
+++ b/tests/tvector.nim
@@ -2,6 +2,7 @@
 import std/[unittest, strformat, sequtils]
 import cppstl/std_vector
 
+
 proc main() =
   suite "CppVector":
     test "constructor, size/len, empty":
@@ -445,4 +446,6 @@ proc main() =
       check v1 == @['w', 'x', 'y', 'z'].toCppVector()
       check v2 == @['a', 'b', 'c'].toCppVector()
 
-main()
+when isMainModule:
+  main()
+