Popping elements off end of an unreferenced array, using &$value.
---( Array with 1 element(s): )---
--> State of array before loop:
array(1) {
  [0]=>
  string(3) "v.0"
}
--> Do loop:
     iteration 0:  $k=0; $v=v.0
--> State of array after loop:
array(0) {
}

---( Array with 2 element(s): )---
--> State of array before loop:
array(2) {
  [0]=>
  string(3) "v.0"
  [1]=>
  string(3) "v.1"
}
--> Do loop:
     iteration 0:  $k=0; $v=v.0
--> State of array after loop:
array(1) {
  [0]=>
  &string(3) "v.0"
}

---( Array with 3 element(s): )---
--> State of array before loop:
array(3) {
  [0]=>
  string(3) "v.0"
  [1]=>
  string(3) "v.1"
  [2]=>
  string(3) "v.2"
}
--> Do loop:
     iteration 0:  $k=0; $v=v.0
     iteration 1:  $k=1; $v=v.1
--> State of array after loop:
array(1) {
  [0]=>
  string(3) "v.0"
}

---( Array with 4 element(s): )---
--> State of array before loop:
array(4) {
  [0]=>
  string(3) "v.0"
  [1]=>
  string(3) "v.1"
  [2]=>
  string(3) "v.2"
  [3]=>
  string(3) "v.3"
}
--> Do loop:
     iteration 0:  $k=0; $v=v.0
     iteration 1:  $k=1; $v=v.1
--> State of array after loop:
array(2) {
  [0]=>
  string(3) "v.0"
  [1]=>
  &string(3) "v.1"
}



Shift elements off start of an unreferenced array, using &$value.
---( Array with 1 element(s): )---
--> State of array before loop:
array(1) {
  [0]=>
  string(3) "v.0"
}
--> Do loop:
     iteration 0:  $k=0; $v=v.0
--> State of array after loop:
array(0) {
}

---( Array with 2 element(s): )---
--> State of array before loop:
array(2) {
  [0]=>
  string(3) "v.0"
  [1]=>
  string(3) "v.1"
}
--> Do loop:
     iteration 0:  $k=0; $v=v.0
     iteration 1:  $k=0; $v=v.1
--> State of array after loop:
array(0) {
}

---( Array with 3 element(s): )---
--> State of array before loop:
array(3) {
  [0]=>
  string(3) "v.0"
  [1]=>
  string(3) "v.1"
  [2]=>
  string(3) "v.2"
}
--> Do loop:
     iteration 0:  $k=0; $v=v.0
     iteration 1:  $k=0; $v=v.1
     iteration 2:  $k=0; $v=v.2
--> State of array after loop:
array(0) {
}

---( Array with 4 element(s): )---
--> State of array before loop:
array(4) {
  [0]=>
  string(3) "v.0"
  [1]=>
  string(3) "v.1"
  [2]=>
  string(3) "v.2"
  [3]=>
  string(3) "v.3"
}
--> Do loop:
     iteration 0:  $k=0; $v=v.0
     iteration 1:  $k=0; $v=v.1
     iteration 2:  $k=0; $v=v.2
     iteration 3:  $k=0; $v=v.3
--> State of array after loop:
array(0) {
}



Remove current element of an unreferenced array, using &$value.
---( Array with 1 element(s): )---
--> State of array before loop:
array(1) {
  [0]=>
  string(3) "v.0"
}
--> Do loop:
     iteration 0:  $k=0; $v=v.0
--> State of array after loop:
array(0) {
}

---( Array with 2 element(s): )---
--> State of array before loop:
array(2) {
  [0]=>
  string(3) "v.0"
  [1]=>
  string(3) "v.1"
}
--> Do loop:
     iteration 0:  $k=0; $v=v.0
     iteration 1:  $k=1; $v=v.1
--> State of array after loop:
array(0) {
}

---( Array with 3 element(s): )---
--> State of array before loop:
array(3) {
  [0]=>
  string(3) "v.0"
  [1]=>
  string(3) "v.1"
  [2]=>
  string(3) "v.2"
}
--> Do loop:
     iteration 0:  $k=0; $v=v.0
     iteration 1:  $k=1; $v=v.1
     iteration 2:  $k=2; $v=v.2
--> State of array after loop:
array(0) {
}

---( Array with 4 element(s): )---
--> State of array before loop:
array(4) {
  [0]=>
  string(3) "v.0"
  [1]=>
  string(3) "v.1"
  [2]=>
  string(3) "v.2"
  [3]=>
  string(3) "v.3"
}
--> Do loop:
     iteration 0:  $k=0; $v=v.0
     iteration 1:  $k=1; $v=v.1
     iteration 2:  $k=2; $v=v.2
     iteration 3:  $k=3; $v=v.3
--> State of array after loop:
array(0) {
}



Adding elements to the end of an unreferenced array, using &$value.
---( Array with 1 element(s): )---
--> State of array before loop:
array(1) {
  [0]=>
  string(3) "v.0"
}
--> Do loop:
     iteration 0:  $k=0; $v=v.0
     iteration 1:  $k=1; $v=new.0
     iteration 2:  $k=2; $v=new.1
     iteration 3:  $k=3; $v=new.2
     iteration 4:  $k=4; $v=new.3
     iteration 5:  $k=5; $v=new.4
  ** Stuck in a loop! **
--> State of array after loop:
array(7) {
  [0]=>
  string(3) "v.0"
  [1]=>
  string(5) "new.0"
  [2]=>
  string(5) "new.1"
  [3]=>
  string(5) "new.2"
  [4]=>
  string(5) "new.3"
  [5]=>
  &string(5) "new.4"
  [6]=>
  string(5) "new.5"
}

---( Array with 2 element(s): )---
--> State of array before loop:
array(2) {
  [0]=>
  string(3) "v.0"
  [1]=>
  string(3) "v.1"
}
--> Do loop:
     iteration 0:  $k=0; $v=v.0
     iteration 1:  $k=1; $v=v.1
     iteration 2:  $k=2; $v=new.0
     iteration 3:  $k=3; $v=new.1
     iteration 4:  $k=4; $v=new.2
     iteration 5:  $k=5; $v=new.3
  ** Stuck in a loop! **
--> State of array after loop:
array(8) {
  [0]=>
  string(3) "v.0"
  [1]=>
  string(3) "v.1"
  [2]=>
  string(5) "new.0"
  [3]=>
  string(5) "new.1"
  [4]=>
  string(5) "new.2"
  [5]=>
  &string(5) "new.3"
  [6]=>
  string(5) "new.4"
  [7]=>
  string(5) "new.5"
}

---( Array with 3 element(s): )---
--> State of array before loop:
array(3) {
  [0]=>
  string(3) "v.0"
  [1]=>
  string(3) "v.1"
  [2]=>
  string(3) "v.2"
}
--> Do loop:
     iteration 0:  $k=0; $v=v.0
     iteration 1:  $k=1; $v=v.1
     iteration 2:  $k=2; $v=v.2
     iteration 3:  $k=3; $v=new.0
     iteration 4:  $k=4; $v=new.1
     iteration 5:  $k=5; $v=new.2
  ** Stuck in a loop! **
--> State of array after loop:
array(9) {
  [0]=>
  string(3) "v.0"
  [1]=>
  string(3) "v.1"
  [2]=>
  string(3) "v.2"
  [3]=>
  string(5) "new.0"
  [4]=>
  string(5) "new.1"
  [5]=>
  &string(5) "new.2"
  [6]=>
  string(5) "new.3"
  [7]=>
  string(5) "new.4"
  [8]=>
  string(5) "new.5"
}

---( Array with 4 element(s): )---
--> State of array before loop:
array(4) {
  [0]=>
  string(3) "v.0"
  [1]=>
  string(3) "v.1"
  [2]=>
  string(3) "v.2"
  [3]=>
  string(3) "v.3"
}
--> Do loop:
     iteration 0:  $k=0; $v=v.0
     iteration 1:  $k=1; $v=v.1
     iteration 2:  $k=2; $v=v.2
     iteration 3:  $k=3; $v=v.3
     iteration 4:  $k=4; $v=new.0
     iteration 5:  $k=5; $v=new.1
  ** Stuck in a loop! **
--> State of array after loop:
array(10) {
  [0]=>
  string(3) "v.0"
  [1]=>
  string(3) "v.1"
  [2]=>
  string(3) "v.2"
  [3]=>
  string(3) "v.3"
  [4]=>
  string(5) "new.0"
  [5]=>
  &string(5) "new.1"
  [6]=>
  string(5) "new.2"
  [7]=>
  string(5) "new.3"
  [8]=>
  string(5) "new.4"
  [9]=>
  string(5) "new.5"
}



Adding elements to the start of an unreferenced array, using &$value.
---( Array with 1 element(s): )---
--> State of array before loop:
array(1) {
  [0]=>
  string(3) "v.0"
}
--> Do loop:
     iteration 0:  $k=0; $v=v.0
--> State of array after loop:
array(2) {
  [0]=>
  string(5) "new.0"
  [1]=>
  &string(3) "v.0"
}

---( Array with 2 element(s): )---
--> State of array before loop:
array(2) {
  [0]=>
  string(3) "v.0"
  [1]=>
  string(3) "v.1"
}
--> Do loop:
     iteration 0:  $k=0; $v=v.0
     iteration 1:  $k=2; $v=v.1
--> State of array after loop:
array(4) {
  [0]=>
  string(5) "new.1"
  [1]=>
  string(5) "new.0"
  [2]=>
  string(3) "v.0"
  [3]=>
  &string(3) "v.1"
}

---( Array with 3 element(s): )---
--> State of array before loop:
array(3) {
  [0]=>
  string(3) "v.0"
  [1]=>
  string(3) "v.1"
  [2]=>
  string(3) "v.2"
}
--> Do loop:
     iteration 0:  $k=0; $v=v.0
     iteration 1:  $k=2; $v=v.1
     iteration 2:  $k=4; $v=v.2
--> State of array after loop:
array(6) {
  [0]=>
  string(5) "new.2"
  [1]=>
  string(5) "new.1"
  [2]=>
  string(5) "new.0"
  [3]=>
  string(3) "v.0"
  [4]=>
  string(3) "v.1"
  [5]=>
  &string(3) "v.2"
}

---( Array with 4 element(s): )---
--> State of array before loop:
array(4) {
  [0]=>
  string(3) "v.0"
  [1]=>
  string(3) "v.1"
  [2]=>
  string(3) "v.2"
  [3]=>
  string(3) "v.3"
}
--> Do loop:
     iteration 0:  $k=0; $v=v.0
     iteration 1:  $k=2; $v=v.1
     iteration 2:  $k=4; $v=v.2
     iteration 3:  $k=6; $v=v.3
--> State of array after loop:
array(8) {
  [0]=>
  string(5) "new.3"
  [1]=>
  string(5) "new.2"
  [2]=>
  string(5) "new.1"
  [3]=>
  string(5) "new.0"
  [4]=>
  string(3) "v.0"
  [5]=>
  string(3) "v.1"
  [6]=>
  string(3) "v.2"
  [7]=>
  &string(3) "v.3"
}