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Remove Head Function
Deque Class

Public Function RemoveHead( _
    Optional ByRef rValue As Variant _
    ) As Boolean

Deletes the value at the head of a deque and returns that value via the argument.
Pops a value off of the stack when a deque is being used as a stack.
Get a value out of the queue when a deque is being used as a queue.

Example #1: 
    Assuming
       Dim dqTemp As New Deque
       dqTemp.AddHead 12
       dqTemp.AddHead "Sam"
       Dim varTemp As Variant
       Dim bResult As Boolean
    for example
       bResult = dqTemp.RemoveHead(varTemp)
    leaves
       bResult = True
       varTemp = "Sam"
    and
       bResult = dqTemp.RemoveHead(varTemp)
    leaves
       bResult = True
       varTemp = 12
Example #2: 
    Assuming
       Dim dqTemp As New Deque
       dqTemp.AddTail 12
       dqTemp.AddTail "Sam"
       Dim varTemp As Variant
       Dim bResult As Boolean
    for example
       bResult = dqTemp.RemoveHead(varTemp)
    leaves
       bResult = True
       varTemp = 12
    and
       bResult = dqTemp.RemoveHead(varTemp)
    leaves
       bResult = True
       varTemp = "Sam"
See also: 
    RemoveTail Function
    RemoveAll Subroutine
    Head Property
    AddHead Subroutine
    QueueRemove Function
    StackPop Function
rValue: Value at the head of the Deque is assigned into variable rValue. rValue must be compatible with the value that is being retrieved from the Deque. rValue is optional and can be omitted in order to remove the value from the Deque without returning the value.
Return Value: Function returns True upon success and False upon failure (when the Deque is empty).
v1.3 BugFix: This function has been changed to return the retrieved value via an argument instead of via its return value. This is so that you do not have to know in advance whether the function will return an object reference or an ordinary value. Also, this Function has been fixed to support the retrieval of Object and DataObject type Values.

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