Archive for January, 2010

The following is a script library written in Lotus Script to allow programmers to use a vector in their Lotus Script code.

Option Declare
Option Base 0

Public Class Vector

	'Private data members
	Private vArray    As Variant
	Private vCapacity As Integer
	Private vSize     As Integer

	Public Sub New()

		'Initialize variables
		Call SetCapacity(0)
		Call SetSize(0)
		Call Reserve(10)

	End Sub

	Public Sub Delete()

		Call EraseAll()

		'Clear the array
		Set vArray = Nothing

	End Sub

	Private Sub SetCapacity(newCapacity As Integer)

		vCapacity = newCapacity

	End Sub

	Public Function Capacity() As Integer

		Capacity = vCapacity

	End Function

	Private Sub SetSize(newSize As Integer)

		vSize = newSize

	End Sub

	Public Function Size() As Integer

		Size = vSize

	End Function

	Public Function Empty() As Boolean

		'Declare variables
		Dim valid As Boolean

		'Get the size
		If (Size() = 0) Then

			valid = True

		Else

			valid = False

		End If

		'Return if the vector is empty
		Empty = valid

	End Function

	Public Sub Reserve(minCapacity As Integer)

		'Declare variables
		Dim openElements As Integer
		Dim newCapacity As Integer

		'Initialize variables
		openElements = Capacity() - Size()
		newCapacity = Capacity()

		'Check if there are any open slots remaining
		If (openElements = 0) Then

			newCapacity = (Capacity() * 1.5)

		End If

		'Make sure that the minimum capacity is stored
		If (newCapacity < minCapacity) Then

			newCapacity = minCapacity

		End If

		'Check if a change to the capacity is being made
		If (Not(Capacity() = newCapacity)) Then

			'Check the size to determine if the array's contents need to be
			'saved while redimensioning the array
			If (Size() = 0) Then

				'Nothing stored yet, perform redim
				Redim vArray(newCapacity)

			Else

				'Keep the array's contents while extending its boundaries
				Redim Preserve array(newCapacity)

			End If

			'Update the capacity
			Call SetCapacity(newCapacity)

		End If

	End Sub

	Public Sub PushBack(newItem As Variant)

		'Check if the passed item/items is actually an array or a list
		If ((Not(Isarray(newItem))) And (Not(Islist(newItem)))) Then

			'Add the single item
			Call AddItem(newItem)

		Else

			'Add multiple items
			Forall item In newItem

				Call AddItem(item)

			End Forall

		End If

	End Sub

	Private Sub AddItem(newItem As Variant)

		'Declare variables
		Dim newSize As Integer

		'Initialize variables
		newSize = Size() + 1

		'Make sure there is enough capacity in the vector
		Call Reserve(newSize)

		'Insert the item into the vector
		If (Isobject(newItem)) Then

			Set vArray(Size()) = newItem

		Else

			vArray(Size()) = newItem

		End If

		'Increment the vector size
		Call SetSize(newSize)

	End Sub

	Public Function At(index As Integer) As Variant

		'Check the vector's index boundaries
		If ((index < 0) Or (index => Size())) Then Error 2000, _
		"[Vector Class]:(Function: At): Index out of bounds."

		'Check if the item is an object
		If (Isobject(vArray(index))) Then

			Set At = vArray(index)

		Else

			At = vArray(index)

		End If

	End Function

	Public Sub Erase(index As Integer)

		'Check if the index is out of bounds
		If ((index < 0) Or (index => Size())) Then Error 2000, _
		"[Vector Class]:(Function: Erase): Index out of bounds."

		'Declare variables
		Dim newArray As Variant
		Dim x As Integer
		Dim y As Integer

		'Initialize variables
		y = 0

		'Make a new array with the same capacity
		Redim newArray(Capacity())

		'Loop through each element of the vector
		For x = 0 To Size() - 1

			'Check if the current index is the one to remove
			If ((x <> index) And (Not(y > Size()))) Then

				'Check if the item is an object
				If (Isobject(vArray(x))) Then

					Set newArray(y) = vArray(x)

				Else

					newArray(y) = vArray(x)

				End If

				'Increment the index counter
				y = y + 1

			End If

		Next x

		'Subtract one from the vector size
		Call SetSize(Size() - 1)

		'Set the new array as the vector
		vArray = newArray

	End Sub

	Public Function BeginIndex() As Integer

		BeginIndex = 0

	End Function

	Public Function EndIndex() As Integer

		EndIndex = Size() - 1

	End Function

	Public Sub EraseAll()

		'Declare variables
		Dim x As Integer

		'Loop through each element of the array
		For x = BeginIndex() To EndIndex()

			'Delete each element of the arra
			'Check if the item is an object
			If (Isobject(vArray(x))) Then

				Set vArray(x) = Nothing

			End If

		Next

		'Reset the size.
		Call SetSize(0)

	End Sub

End Class

Copy the above code and paste into a script library for the database where you would like to use a vector. Then, you can use the example below to use the vector class.

Use "libVector"

Dim vector As New Vector()
dim obj As String

obj = "hello"

'Load any object into the vector.
Call vector.PushBack(obj)
Call vector.PushBack(obj)

'Loop through the vector to retrieve objects.
For i = vector.BeginIndex() To vector.EndIndex()

  Print "Item: " & i & " " & vector.At(i)

Next