Just another update

Task/Extend-your-language/REXX/extend-your-language-1.rexx

@@ -0,0 +1,8 @@
+if2(  some expression that results in a boolean value,  some other expression that results in a boolean value.)
+
+    select
+    when if.11  {condition 1 & 2  are true}   then  perform-a-REXX-statement.
+    when if.10  {condition 1       is true}     "      "    "   "      "
+    when if.01  {condition 2       is true}     "      "    "   "      "
+    when if.00  {no condition      is true}     "      "    "   "      "
+    end

Task/Extend-your-language/REXX/extend-your-language-2.rexx

@@ -0,0 +1,20 @@
+/*REXX program introduces   IF2,   a type of four-way compound  IF:     */
+
+  do n=10  to 20                       /*put DO loop through it's paces.*/
+                                       /* [↓]  divisible by 2 and/or 3? */
+  if2( n//2==0, n//3==0)               /*use the four-way  IF statement.*/
+      select                           /*now, test the 4 possible cases.*/
+      when if.11  then say n  "is divisible by both two and three."
+      when if.10  then say n  "is divisible by two, but not by three."
+      when if.01  then say n  "is divisible by three, but not by two."
+      when if.00  then say n  "is neither divisible by two, nor by three."
+      otherwise nop                    /* ◄─┬─this statement is optional*/
+      end   /*select*/                 /*   ├─ and only exists in case  */
+  end       /*n*/                      /*   ├─ one or more WHENs (above)*/
+                                       /*   └─ are omitted.             */
+exit                                   /*stick a fork in it, we're done.*/
+/*──────────────────────────────────IF2 routine─────────────────────────*/
+if2: parse arg if.10, if.01            /*assign the cases  10  and  01  */
+               if.11= if.10 & if.01    /*   "    "  case   11           */
+               if.00= \(if.10 | if.01) /*   "    "    "    00           */
+return ''                              /*return to the invoker of  IF2. */