Data update

Task/Null-object/Ada/null-object.adb

@@ -0,0 +1,5 @@
+with Ada.Text_Io;
+
+if Object = null then
+   Ada.Text_Io.Put_line("object is null");
+end if;

Task/Null-object/AutoIt/null-object.au3

@@ -0,0 +1,2 @@
+Local $object = Null
+If $object = Null Then MsgBox(0, "NULL", "Object is null")

Task/Null-object/COBOL/null-object.cob

@@ -0,0 +1,43 @@
+       identification division.
+       program-id. null-objects.
+       remarks. test with cobc -x -j null-objects.cob
+
+       data division.
+       working-storage section.
+       01 thing-not-thing      usage pointer.
+
+      *> call a subprogram
+      *>   with one null pointer
+      *>   an omitted parameter
+      *>   and expect void return (callee returning omitted)
+      *>   and do not touch default return-code (returning nothing)
+       procedure division.
+       call "test-null" using thing-not-thing omitted returning nothing
+       goback.
+       end program null-objects.
+
+      *> Test for pointer to null (still a real thing that takes space)
+      *>   and an omitted parameter, (call frame has placeholder)
+      *>   and finally, return void, (omitted)
+       identification division.
+       program-id. test-null.
+
+       data division.
+       linkage section.
+       01 thing-one            usage pointer.
+       01 thing-two            pic x.
+
+       procedure division using
+           thing-one
+           optional thing-two
+           returning omitted.
+
+       if thing-one equal null then
+           display "thing-one pointer to null" upon syserr
+       end-if
+
+       if thing-two omitted then
+           display "no thing-two was passed" upon syserr
+       end-if
+       goback.
+       end program test-null.

Task/Null-object/Chapel/null-object.chpl

@@ -0,0 +1,3 @@
+class C { };
+var c : owned C?; // is nil
+writeln(if c == nil then "nil" else "something");

Task/Null-object/EMal/null-object.emal

@@ -6,8 +6,8 @@
 var a # defaults to null
 int b # defaults to 0
 void c # only one allowed value: null
-writeLine("nullable var equals to not nullable int: " + (a == b)) # allowed, false
+writeLine("nullable var equals to not nullable int: " + (a æ b)) # allowed, false
 ^| if the data type of a is void we are sure that a is null |^
-writeLine("type of a equals to Void data type: " + (generic!a == void)) # true
-writeLine("integer value " + b + " equals to null: " + (b == null)) # allowed, always false
-writeLine("a void value equals to null: " + (c == null)) # always true
+writeLine("type of a equals to Void data type: " + (generic!a æ void)) # true
+writeLine("integer value " + b + " equals to null: " + (b æ null)) # allowed, always false
+writeLine("a void value equals to null: " + (c æ null)) # always true

Task/Null-object/PowerShell/null-object.ps1

@@ -0,0 +1,3 @@
+if ($null -eq $object) {
+    ...
+}

Task/Null-object/Rebol/null-object-1.rebol

@@ -0,0 +1,3 @@
+x: none
+
+print ["x"  either none? x ["is"]["isn't"]  "none."]

Task/Null-object/Rebol/null-object-2.rebol

@@ -0,0 +1,2 @@
+unset? get/any 'some-var
+unset? get 'some-var