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I have this line of code:
I'd like it to be this:Code:If (ShuffleTypeID <> idx_ShuffleType_EquipBest) And (ShuffleTypeID <> idx_ShuffleType_EquipWorst) Then Exit Function
To see what that does I did this:Code:If ShuffleTypeID <> (idx_ShuffleType_EquipBest Or idx_ShuffleType_EquipWorst) Then Exit Function
I don't understand that.Code:Sub SomeSub
Dim x As Integer
x = 2
MsgBox x = 5 or 7 ' Returns 7 instead of False.
I didn't put the 5 or 7 in Parens.
It still returned False.Code:Sub SomeSub
Dim x As Integer
x = 2
MsgBox x = (5 Or 7) ' Returns False.
MsgBox x = (2 or 7) ' Returns False.
Do you really want bit operations or do you try to shortcut some boolean logic?
An OR on bitvalues will fill all positions with 1 if there is a 1 on the position in one of the valuesCode:0 = 0000
1 = 0001
2 = 0010
3 = 0011
4 = 0100
5 = 0101
6 = 0110
7 = 0111
5 or 7:
5 = 0101
7 = 0111
----------
x = 0111 -> value 7
2 or 7:
2 = 0010
7 = 0111
----------
x = 0111 -> value 7
Your code:
x = 2
n = 5 Or 7 ' -> 7
MsgBox x = n -> False
x = 2
n = 2 Or 7 ' -> 7
MsgBox x = n -> False
I don't know the difference. But yes, I'm just trying to make it shorter and clearer.
Essentially my goal with all my code is to make it so obvious what it's doing that comments are optional (I know I should add them anyway).
But basically I would rather read through the code and know what it's doing instead of reading comments.
Would XOR work? I'll try that and see what it does.
Result: Nope.
What do want to achieve?
A shortcut to "(x = 2) or (x = 7)"?
Yes.
If (x <> 2) And (x <> 7) Then Exit Function. ' One Case must be True to continue (x = 2) or (x = 7) continues.
I'm just trying to shorten one line of code because I write this same line of code a lot.
And I think it's much faster to read if it's what I'm trying to do.
This is the sub in question not that it matter. It's just one line of code near the top:
Code:Private Function EquipBestWorstItems(ByRef PlayerItems As cItems, ByRef ShuffleTypeID As SHUFFLE_TYPE_INDEX) As Long
Dim m_item As cItem
Dim m_EquippedItem As cItem
Dim nResult As Long
If Not ValidObject(PlayerItems) Then Exit Function
If PlayerItems.Count = 0 Then Exit Function
' The next line is the one I want to short-ciruit:
If (ShuffleTypeID <> idx_ShuffleType_EquipBest) And (ShuffleTypeID <> idx_ShuffleType_EquipWorst) Then Exit Function
For Each m_item In PlayerItems
Set m_EquippedItem = EquippedItem(m_item.ItemSlotID)
If ValidObject(m_EquippedItem) Then ' Item Slot Is Equipped. Check if m_Item is Better or Worse.
Select Case ShuffleTypeID
Case idx_ShuffleType_EquipBest ' Equip if Better.
If m_item.LevelRequirement > m_EquippedItem.LevelRequirement Then
nResult = EquipItem(m_item, PlayerItems, idx_AcquisitionMethod_Distribute)
End If
Case idx_ShuffleType_EquipWorst ' Equip if Worse.
If m_item.LevelRequirement < m_EquippedItem.LevelRequirement Then
nResult = EquipItem(m_item, PlayerItems, idx_AcquisitionMethod_Distribute)
End If
End Select
Else ' Item Slot is Not Equipped. Any Item is better.
nResult = EquipItem(m_item, PlayerItems, idx_AcquisitionMethod_Distribute)
End If
If nResult <> 1 Then TransferItem m_item, PlayerItems, BackpackItems, idx_AcquisitionMethod_Distribute ' Equip failed. Store Item in Backpack.
Next m_item
EquipBestWorstItems = 1
End Function
Why not use Select Case?Quote:
Originally Posted by cafeenman
Code:Select Case ShuffleTypeID
Case idx_ShuffleType_EquipBest, _
idx_ShuffleType_EquipWorst
' Do Something
End Select
Or how about a function?Quote:
Originally Posted by cafeenman
Code:Function IsBestOrWorstShuffleType(ByVal ShuffleTypeId As eShuffleTypeId) As Boolean
IsBestOrWorstShuffleType = (ShuffleTypeId = idx_ShuffleType_EquipBest) Or _
(ShuffleTypeId = idx_ShuffleType_EquipWorst)
End Function
One of the advantages of a function is that if your logic needs to change down the road, you only need to modify the code in one place (and perhaps do a global find/replace on the old function name).
That would work.
More Generically I'd probably name it:
Function OneOfTheseIsTrue(ByRef ValueSought, ByRef Value1, ByRef Value2) as Boolean
Actually, make thelast arguments a paramarray and loop through it until one is true.
CafeenMan luvs functions. Just didn't think about it in this circumstance.
Thanks. :)
LOL... actually....
Function NoneOfTheseAreTrue is even better I think.
That way instead of always using Not to get out, just get out.
E.g.
If Not OneOfTheseIsTrue(...) Then Exit Function
or
If NoneOfTheseAreTrue(...) Then Exit Function
Just don't use any procedure with a ParamArray in a performance critical inner loop and the game won't lag too much :-))Quote:
Originally Posted by cafeenman
I personally would always use plain If statement with a single Or operator not only for performance but for readability too.
cheers,
</wqw>
Haven't tested it yet but this is my first shot at it:
Code:Public Function NoneAreTrue(ByRef ValueSought, ParamArray Values()) As Boolean
Dim n As Long
For n = LBound(Values) To UBound(Values)
If Values(n) = ValueSought Then Exit Function
Next n
NoneAreTrue = True
End Function
Code:
' Old
If (ShuffleTypeID <> idx_ShuffleType_EquipBest) And (ShuffleTypeID <> idx_ShuffleType_EquipWorst) Then Exit Function
' New. Not much shorter and not sure it's easier to follow.
If NoneAreTrue(ShuffleTypeID, idx_ShuffleType_EquipBest, idx_ShuffleType_EquipWorst) Then Exit Function
VB6 doesn't have separate sets of boolean versus bitwise operators, like other C-like languages do. For instance, in C, we've got & (bitwise) versus && (boolean), or | (bitwise) versus || (boolean). And there are others as well.
In VB6, we've just got "And" and "Or" (and the others). And they're all bitwise, not boolean. Now, we do have a boolean variable type, which is just a special case of an Integer (two byte) variable, where it attempts to have a value of either &h0000 (0) or &hFFFF (-1).
But, because "And" and "Or" are bitwise (and not boolean), things can get confusing. If you just want a True or False answer, and you're dealing with variables that aren't initially Boolean variables, the easiest thing to do is just cast them to Boolean with the CBool() function before you start. That way, everything will be done as a boolean operation.
To explain a bit, if we're starting with either a &h0000 or &hFFFF, at that point there's no distinction between a bitwise operation and a boolean operation, so our "And" and "Or" will work like boolean operators, solving any problems.
If you just want a trivial example of how things can get confusing, here are two different evaluations:
Try it if you don't believe me.Code:Dim i As Integer, j As Integer
Dim b As Boolean
i = 1
j = 2
b = i And j ' In this case, b will be False.
b = CBool(i) And CBool(j) ' In this case, b will be True.
I won't go into all the nitty-gritty of how bitwise actually works, but again, if it's starting with Boolean variables, the "And" and "Or" will effectively work like Boolean operators. But, if we're starting with something that's not Boolean, that's when the outcome can start getting tricky, as in the "b = i And j" line above.
Just to add a final comment, once you understand bitwise (under the hood), it does all make sense. But, if we're just after boolean answers, it's often not necessary to get into all the details of bitwise.
Because that's going in the opposite direction - longer code.Quote:
Originally Posted by jpbro
Quote:
Originally Posted by cafeenman
Code:Private Sub Command1_Click()
Dim x As Long
x = 2
Debug.Print ValueIn(x, 5, 7)
Debug.Print ValueIn(x, 1, 3, 4, 5, 7)
Debug.Print ValueIn(x, 2, 7)
End Sub
Private Function ValueIn(ByVal Value As Long, ParamArray Values()) As Boolean
Dim i As Long
For i = LBound(Values) To UBound(Values)
If Values(i) = Value Then
ValueIn = True
Exit For
End If
Next i
End Function
See #17. :)
Ah, sorry missed it :)Quote:
Originally Posted by cafeenman
If you want to use a bit field, you can use the AND operator to perform a single test:-Quote:
Originally Posted by cafeenman
The bread and butter is this line:-Code:Private Sub Form_Load()
Dim idx_ShuffleType_EquipBest As Long
Dim idx_ShuffleType_EquipWorst As Long
Dim flag1 As Long
Dim flag2 As Long
Dim BestAndWorst As Long
Dim ShuffleTypeID1 As Long
Dim ShuffleTypeID2 As Long
Dim ShuffleTypeID3 As Long
Dim ShuffleTypeID4 As Long
idx_ShuffleType_EquipBest = 1
idx_ShuffleType_EquipWorst = 2
'This variable has the best and worst flags set
BestAndWorst = idx_ShuffleType_EquipBest Or idx_ShuffleType_EquipWorst
'Extra flags to make things interesting
flag1 = 4
flag2 = 8
flag3 = 16
ShuffleTypeID1 = idx_ShuffleType_EquipBest
ShuffleTypeID2 = idx_ShuffleType_EquipWorst
ShuffleTypeID3 = flag1 Or flag2 Or flag3 Or idx_ShuffleType_EquipBest
'This is the only one that isn't best or worst so
'it should invoke an exit
ShuffleTypeID4 = flag3 Or flag2
'Only one the last one should print "Exit Function" as it's the only that is neither best or worst
'****************************************************************************************************
If Not CBool(ShuffleTypeID1 And BestAndWorst) Then Debug.Print "Exit Function" Else Debug.Print "Don't Exit Function"
If Not CBool(ShuffleTypeID2 And BestAndWorst) Then Debug.Print "Exit Function" Else Debug.Print "Don't Exit Function"
If Not CBool(ShuffleTypeID3 And BestAndWorst) Then Debug.Print "Exit Function" Else Debug.Print "Don't Exit Function"
If Not CBool(ShuffleTypeID4 And BestAndWorst) Then Debug.Print "Exit Function" Else Debug.Print "Don't Exit Function"
End Sub
Which in your code would be:-Code:If Not CBool(ShuffleTypeID1 And BestAndWorst) Then Debug.Print "Exit Function" Else Debug.Print "Don't Exit Function"
The idea here is that if either the best or worst bits are set then ANDing with with a bit field where both these bits are set will always return non-zero.Code:If Not CBool(ShuffleTypeID And BestAndWorst) Then Exit Function
So if I wanted to reduce that to one line of code then it would be thus?
Code:If Not CBool(ShuffleTypeID And (idx_ShuffleType_EquipBest Or idx_ShuffleType_EquipWorst)) Then Exit Function
Yes. However, there is a very important caveat, you must be operating on bit fields. What this means is that the values you're dealing cannot be arbitrary. Each state must correspond to a single bit. You can see that in the code I posted:-Quote:
Originally Posted by cafeenman
Notice that they increment in powers of 2. This is what allows them to be combined into a single bit field by the OR operator.Code:idx_ShuffleType_EquipBest = 1
idx_ShuffleType_EquipWorst = 2
flag1 = 4
flag2 = 8
flag3 = 16
I'm going to pass on this method although I can see it has a lot of value for other things.
But it would require translation and conversion because everything in the program is die-rolls that return 1 through number of die sides.
nDieRoll = RollDie(d6)
ShuffleType = 2 ^ (nDieRoll - 1) '
Just to check my math.
rolls
1: (2 ^ (1 - 1) = 1
2: (2 ^ (2 - 1) = 2
3: (2 ^ (3 - 1) = 4
4: (2 ^ (4 - 1) = 8
5: etc..
6:
Actually it's not so bad since this is done in only one Function. All functions called by this function are sent the enum value, not the die roll.
Code:Public Enum SHUFFLE_TYPE_INDEX
idx_ShuffleType_EquipRandom = 1 ' 1 Equip Random Items.
idx_ShuffleType_EquipBest ' 2 Prioritize Highest Level Items.
idx_ShuffleType_EquipWorst ' 3 Prioritize Lowest Level Item.
idx_ShuffleType_BackpackPriority ' 4 Prioritize Backpack Items.
idx_ShuffleType_EquippedPriority ' 5 Prioritize Equipped Items.
idx_ShuffleType_UnequipAll ' 6 Store All Items (go naked).
End Enum
Public Const MIN_SHUFFLE_TYPE_INDEX As Long = idx_ShuffleType_EquipRandom
Public Const MAX_SHUFFLE_TYPE_INDEX As Long = idx_ShuffleType_UnequipAll
Sub SomeSub
dim nShuffleType as SHUFFLE_TYPE_INDEX
nShuffleType = RollDie(MAX_SHUFFLE_TYPE_INDEX )
End Sub
Oh I understand now. ShuffleType is not actually a bit field. You just want to simplify the comparisons. Well you can do this using primes if you wanted to:-Quote:
Originally Posted by cafeenman
The only caveat here is that you must use prime numbers for the enum values in order for this to work.Code:Public Enum SHUFFLE_TYPE_INDEX
idx_ShuffleType_EquipRandom = 2 ' 1 Equip Random Items.
idx_ShuffleType_EquipBest = 3 ' 2 Prioritize Highest Level Items.
idx_ShuffleType_EquipWorst = 5 ' 3 Prioritize Lowest Level Item.
idx_ShuffleType_BackpackPriority = 7 ' 4 Prioritize Backpack Items.
idx_ShuffleType_EquippedPriority = 11 ' 5 Prioritize Equipped Items.
idx_ShuffleType_UnequipAll = 13 ' 6 Store All Items (go naked).
End Enum
Private Sub Form_Load()
Dim st(0 To 5) As SHUFFLE_TYPE_INDEX
st(0) = idx_ShuffleType_EquipRandom
st(1) = idx_ShuffleType_EquipBest
st(2) = idx_ShuffleType_EquipWorst
st(3) = idx_ShuffleType_BackpackPriority
st(4) = idx_ShuffleType_EquippedPriority
st(5) = idx_ShuffleType_UnequipAll
For i = LBound(st) To UBound(st)
'Filter out all options that are not the best and not the worst
If (idx_ShuffleType_EquipBest * idx_ShuffleType_EquipWorst) Mod st(i) Then Debug.Print st(i) & " : " & "Exit Function"
Next
End Sub