Lazy Evaluation Example In Visual Basic

(Bad ;-) Example of using LazyEvaluation in a VisualBasic program.

(The objective of this exercise is to show that LazyEvaluation is complex and slow: That you shouldn't use it unless the computation is expensive/difficult, and the result won't be needed in many cases.)

Well, you've shown that it's complex (and maybe slow, got any numbers?) in VB. Since I'm not in a VB shop, what do I care?

I get it: if you take extra steps to avoid adding the numbers, then when you add the numbers you end up taking extra steps.

I suppose what we need now is an EagerEvaluationExampleInHaskell to show that LazyEvaluation is still complex and slow by comparison.

---

Example taken from the LazyEvaluation page: Compute...

    Result = (a + b) + (c + d) + (a + b)

using LazyEvaluation.

Usage:

    Dim lLazy   As New clsLazyEvaluation
    lLazy.a = a
    lLazy.b = b
    lLazy.c = c
    lLazy.d = d
    '   (One normally assumes that there is some "distance" in time and/or code at this point.)
    Result = lLazy.Result

Class definition for clsLazyEvaluation:

    Option Explicit

    '
    '   Attributes of the class:
    '
    Private mintA           As Integer      ' Inputs
    Private mintB           As Integer
    Private mintC           As Integer
    Private mintD           As Integer

    Private mblnHaveResult  As Boolean      ' Internal
    Private mintResult      As Integer      ' Output

    Private Sub Class_Initialize()
        mblnHaveResult = False
    End Sub

    Public Property Let a(ByVal pintNewValue As Integer)
        mintA = pintNewValue
    End Property

    Public Property Get a() As Integer
        a = mintA
    End Property

    Public Property Let b(ByVal pintNewValue As Integer)
        mintB = pintNewValue
    End Property

    Public Property Get b() As Integer
        b = mintB
    End Property

    Public Property Let c(ByVal pintNewValue As Integer)
        mintC = pintNewValue
    End Property

    Public Property Get c() As Integer
        c = mintC
    End Property

    Public Property Let d(ByVal pintNewValue As Integer)
        mintD = pintNewValue
    End Property

    Public Property Get d() As Integer
        d = mintD
    End Property

    Public Property Get Result() As Integer
        If Not mblnHaveResult Then
            mintResult = (mintA + mintB) + (mintC + mintD) + (mintA + mintB)
            mblnHaveResult = True
        End If
        Result = mintResult
    End Property

---

Very interesting, but why do your values come in pints and why are you growing mint? mint = member int, pint = parameter int

CategoryLazyPattern