better setops docs (#16236)

* js module also uses runnableExamples

* better setops docs

* Update lib/system/setops.nim

* better

* Update lib/system/setops.nim

* Update lib/system/setops.nim

* better

* better

lib/system/setops.nim

@@ -1,94 +1,86 @@
-proc incl*[T](x: var set[T], y: T) {.magic: "Incl", noSideEffect.}
-  ## Includes element ``y`` in the set ``x``.
+func incl*[T](x: var set[T], y: T) {.magic: "Incl".} =
+  ## Includes element `y` in the set `x`.
   ##
-  ## This is the same as ``x = x + {y}``, but it might be more efficient.
-  ##
-  ## .. code-block:: Nim
-  ##   var a = {1, 3, 5}
-  ##   a.incl(2) # a <- {1, 2, 3, 5}
-  ##   a.incl(4) # a <- {1, 2, 3, 4, 5}
+  ## This is the same as `x = x + {y}`, but it might be more efficient.
+  runnableExamples:
+    var a = {1, 3, 5}
+    a.incl(2)
+    assert a == {1, 2, 3, 5}
+    a.incl(4)
+    assert a == {1, 2, 3, 4, 5}
 
 template incl*[T](x: var set[T], y: set[T]) =
-  ## Includes the set ``y`` in the set ``x``.
-  ##
-  ## .. code-block:: Nim
-  ##   var a = {1, 3, 5, 7}
-  ##   var b = {4, 5, 6}
-  ##   a.incl(b)  # a <- {1, 3, 4, 5, 6, 7}
+  ## Includes the set `y` in the set `x`.
+  runnableExamples:
+    var a = {1, 3, 5, 7}
+    var b = {4, 5, 6}
+    a.incl(b)
+    assert a == {1, 3, 4, 5, 6, 7}
   x = x + y
 
-proc excl*[T](x: var set[T], y: T) {.magic: "Excl", noSideEffect.}
-  ## Excludes element ``y`` from the set ``x``.
+func excl*[T](x: var set[T], y: T) {.magic: "Excl".} =
+  ## Excludes element `y` from the set `x`.
   ##
-  ## This is the same as ``x = x - {y}``, but it might be more efficient.
-  ##
-  ## .. code-block:: Nim
-  ##   var b = {2, 3, 5, 6, 12, 545}
-  ##   b.excl(5)  # b <- {2, 3, 6, 12, 545}
+  ## This is the same as `x = x - {y}`, but it might be more efficient.
+  runnableExamples:
+    var b = {2, 3, 5, 6, 12, 545}
+    b.excl(5)
+    assert b == {2, 3, 6, 12, 545}
 
 template excl*[T](x: var set[T], y: set[T]) =
-  ## Excludes the set ``y`` from the set ``x``.
-  ##
-  ## .. code-block:: Nim
-  ##   var a = {1, 3, 5, 7}
-  ##   var b = {3, 4, 5}
-  ##   a.excl(b)  # a <- {1, 7}
+  ## Excludes the set `y` from the set `x`.
+  runnableExamples:
+    var a = {1, 3, 5, 7}
+    var b = {3, 4, 5}
+    a.excl(b) 
+    assert a == {1, 7}
   x = x - y
 
-proc card*[T](x: set[T]): int {.magic: "Card", noSideEffect.}
-  ## Returns the cardinality of the set ``x``, i.e. the number of elements
+func card*[T](x: set[T]): int {.magic: "Card".} =
+  ## Returns the cardinality of the set `x`, i.e. the number of elements
   ## in the set.
-  ##
-  ## .. code-block:: Nim
-  ##   var a = {1, 3, 5, 7}
-  ##   echo card(a) # => 4
+  runnableExamples:
+    var a = {1, 3, 5, 7}
+    assert card(a) == 4
+    var b = {1, 3, 5, 7, 5}
+    assert card(b) == 4 # repeated 5 doesn't count
 
-proc len*[T](x: set[T]): int {.magic: "Card", noSideEffect.}
+func len*[T](x: set[T]): int {.magic: "Card".}
   ## An alias for `card(x)`.
 
 
-proc `*`*[T](x, y: set[T]): set[T] {.magic: "MulSet", noSideEffect.}
+func `*`*[T](x, y: set[T]): set[T] {.magic: "MulSet".} =
   ## This operator computes the intersection of two sets.
-  ##
-  ## .. code-block:: Nim
-  ##   let
-  ##     a = {1, 2, 3}
-  ##     b = {2, 3, 4}
-  ##   echo a * b # => {2, 3}
-proc `+`*[T](x, y: set[T]): set[T] {.magic: "PlusSet", noSideEffect.}
-  ## This operator computes the union of two sets.
-  ##
-  ## .. code-block:: Nim
-  ##   let
-  ##     a = {1, 2, 3}
-  ##     b = {2, 3, 4}
-  ##   echo a + b # => {1, 2, 3, 4}
-proc `-`*[T](x, y: set[T]): set[T] {.magic: "MinusSet", noSideEffect.}
-  ## This operator computes the difference of two sets.
-  ##
-  ## .. code-block:: Nim
-  ##   let
-  ##     a = {1, 2, 3}
-  ##     b = {2, 3, 4}
-  ##   echo a - b # => {1}
+  runnableExamples:
+    assert {1, 2, 3} * {2, 3, 4} == {2, 3}
 
-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.
+func `+`*[T](x, y: set[T]): set[T] {.magic: "PlusSet".} =
+  ## This operator computes the union of two sets.
+  runnableExamples:
+    assert {1, 2, 3} + {2, 3, 4} == {1, 2, 3, 4}
+
+func `-`*[T](x, y: set[T]): set[T] {.magic: "MinusSet".} =
+  ## This operator computes the difference of two sets.
+  runnableExamples:
+    assert {1, 2, 3} - {2, 3, 4} == {1}
+
+func contains*[T](x: set[T], y: T): bool {.magic: "InSet".} =
+  ## One should overload this proc if one wants to overload the `in` operator.
   ##
-  ## The parameters are in reverse order! ``a in b`` is a template for
-  ## ``contains(b, a)``.
+  ## The parameters are in reverse order! `a in b` is a template for
+  ## `contains(b, a)`.
   ## This is because the unification algorithm that Nim uses for overload
   ## resolution works from left to right.
-  ## But for the ``in`` operator that would be the wrong direction for this
+  ## But for the `in` operator that would be the wrong direction for this
   ## piece of code:
-  ##
-  ## .. code-block:: Nim
-  ##   var s: set[range['a'..'z']] = {'a'..'c'}
-  ##   assert s.contains('c')
-  ##   assert 'b' in s
-  ##
-  ## If ``in`` had been declared as ``[T](elem: T, s: set[T])`` then ``T`` would
-  ## have been bound to ``char``. But ``s`` is not compatible to type
-  ## ``set[char]``! The solution is to bind ``T`` to ``range['a'..'z']``. This
-  ## is achieved by reversing the parameters for ``contains``; ``in`` then
+  runnableExamples:
+    var s: set[range['a'..'z']] = {'a'..'c'}
+    assert s.contains('c')
+    assert 'b' in s
+    assert 'd' notin s
+    assert set['a'..'z'] is set[range['a'..'z']]
+  ## If `in` had been declared as `[T](elem: T, s: set[T])` then `T` would
+  ## have been bound to `char`. But `s` is not compatible to type
+  ## `set[char]`! The solution is to bind `T` to `range['a'..'z']`. This
+  ## is achieved by reversing the parameters for `contains`; `in` then
   ## passes its arguments in reverse order.