--- /dev/null
+alias _dont ""
+alias _do "$*"
+
+set _ifstack ""
+alias : "$_ifstack $*"
+
+alias :ifeq "set _ifnew_$1 _dont; set _ifnew_$2 _do; _ifeq_2 _ifnew_$1"
+alias :ifneq "set _ifnew_$1 _do; set _ifnew_$2 _dont; _ifeq_2 _ifnew_$1"
+alias _ifeq_2 "set _ifstack \"${$1} $_ifstack\""
+alias :else "_else_2$_ifstack"
+alias _else_2_do "set _ifstack \"_dont ${* q?}\""
+alias _else_2_dont "set _ifstack \"_do ${* q?}\""
+alias :endif "_endif_2 $_ifstack"
+alias _endif_2 "set _ifstack \"${2- q?}\""
+
+// EXAMPLE:
+// :ifeq "$a" "$b"
+// :ifeq "$a" "$c"
+// : echo "a == b == c"
+// :else
+// : echo "a == b != c"
+// :endif
+// :else
+// :ifeq "$a" "$c"
+// : echo "a == c != b"
+// :else
+// :ifeq "$b" "$c"
+// : echo "b == c != a"
+// :else
+// : echo "a != b != c != a"
+// :endif
+// :endif
+// :endif