VBA Rubberducking

7:00 PM

hm. Technically, that's just VBA's implicit voodoo conversion

no it's weirder than that

Sub test()
    Dim a As Boolean
    a = 2

    Dim b As Boolean
    b = CBool(2)

    Debug.Print CInt(a), a, Not a
    Debug.Print CInt(b), b, Not b
End Sub

-1            True          False
-1            True          False

M.Doerner

I do not see the problem.

Mathieu Guindon

there's no problem in that code here

4

A: VBA: Why would the Not operator stop working?

I believe the explanation has to do with how older programming languages (WordBasic and early VBA) stored the integer values of True and False. In those days, True = -1 and False = 0. Newer programming languages still use 0 for False, but 1 for True. The majority of Word's Boolean type properti...

but it contradicts how Word does it

IvenBach

That is unsettling.

Mathieu Guindon

somehow CInt(X) returns 2

@IvenBach very

IvenBach

7:03 PM

Along the lines of shaking a fundamental belief about Boolean logic unsettling.

this

Still not getting it.

the problem would manifest itself if you played fast'n'loose with the data type but in this case, it seems to be expected that Not x = False

IvenBach

X = True then X = Not X should produce a value of what?

Mathieu Guindon

literally, Debug.Print Cint(X) (with X As Boolean) outputs 2 and that is not supposed to happen

this

Ok, i see hte problem now

Sub test()
    Dim a As Boolean
    a = 2

    Dim b As Boolean
    b = CBool(2)

    Dim c As Boolean
    Dim d As Boolean

    c = Not a
    d = Not d

    Debug.Print CInt(a), a, Not a, c
    Debug.Print CInt(b), b, Not b, d
End Sub

-1            True          False         False
-1            True          False         True

Mathieu Guindon

I don't

that doesn't repro

I can't repro it outside of Word

this

7:07 PM

that was from Excel

facepalm

Mathieu Guindon

yeah, and nothing unexpected in the output

M.Doerner

did you intend d = Not d?

this

no

that was my mistake

should be d = Not b

and corrected, then it behaves as expected

so... back to my original position --- not seeing the problem, exactly.

Mathieu Guindon

but make a table in Word and then try the OP's code

somehow, Boolean is retaining its underlying value of 1 instead of being stomped to -1 like everywhere else

this

here's a better demo, I think.

Private Type t1
    b As Boolean
End Type

Private Type t2
    i As Integer
End Type

Public Sub testbits()
    Dim b As t1
    Dim i As t2
    Dim i2 As t2

    i.i = 256
    LSet b = i

    LSet i2 = b

    Debug.Print i.i, b.b, i2.i
End Sub

 256          True           256

This seems a good case as to why you should not If Not <condition> Then but rather If <condition> = False Then

Mathieu Guindon

7:13 PM

using OP's code, I had CInt(X) return 2. With X declared As Boolean, my (previous?) understanding of VBA was that this would be impossible and CInt(X) could only ever be 0 or -1

this

But see, if I LSet, I'm circumventing VB's safeguards.

Mathieu Guindon

@this if we can't trust that Boolean is 0 or -1, then any Not, Or, And, XOr logic goes out the window

this

We can observe similar problems with calling API that ordinarily returns 1 for result.

Well, if you define it As Boolean, then that is not a problem. The safeguard makes sure it's correct

it's only when you directly write to the memory then strange thing can happen

Realistically, that is no different from C/C++ which only uses 1 as a convention

IvenBach

How are the circumventing the safeguards with the given code?

this

but in all of its tests, it's always if(<condition> = 0) {failed();} else {succeeded();} (or perhaps if(!<condition>) {succeeded();} else {failed();})

Word's dumb?

IvenBach

7:17 PM

I agree that words are dumb. Motion to revert to grunting and pointing has passed!

this

uh, Word, not words. ;-)

IvenBach

#Words ;p

this

Anyway: That's why I usually advocate for writing conditions in either If <condition> Then or If <condition> = False Then; anything else is just a time bomb

it also bears pointing out that Not, And, and Or are bitwise operators, not logical operators, even though we pretend it could be used like logical ones.

and because we don't have an Option Strict, it's too easy to accidentally end up with a implicit Variant result from a <condition>; so for that reason, I can't even trust If someFunctionThatReturnsABoolean() = True Then

IvenBach

I agree with your #BeltsAndSuspenders view the more I learn. If foo = (True | False) Then just feels wrong to me.

this

If foo = True Then is wrong, indeed but If foo = False Then is correct.

If Not foo Then is wrong.

Implicitly all conditions are basically If <condition> <> False Then

so if you put it in a table, you can see why If Not foo Then could end up wrong

Mathieu Guindon

7:26 PM

@IvenBach not only that, I've been telling everyone it's redundant, for years!

this

same with If foo = True Then

In short, you want to ensure that all your condition can only yield a falsy result because falsy result is the only one that's constant everywhere.... Everyone (well, except JS...) expect a falsy result to be one that's equal to 0.

But not everyone agrees on what constitutes a truthy result -- some say 1, others say -1, yet other say true, etc. etc. Confusion abounds.

IvenBach

@MathieuGuindon ~~Winter~~ Christmas is coming. You can gift everyone you ever told to just do If foo Then an apology. Check that list not -3 times though.

this

uh? No.

If foo Then is correct.

It's If foo = True Then that's not right.

But the converse does not hold!

e.g. If Not foo Then is wrong; you want If foo = False Then

M.Doerner

My take on this is simply Only use things with explicit boolean type in conditionals.

Except in languages like Pyhton that really expect you to put just anything into conditionals and boolean operators.

It is even in the style guide.

this

the issue, though is that you can't guarantee that you won't get hit with an implicit conversion when evaluating an expression. The above works in all cases, explicit booleans or not.

and I prefer a coding style that is always correct even in face of absurdity.

M.Doerner

7:35 PM

I think the programming language should really take care to always convert to boolean before applying logical operators.

The stupid thing in VBA is that they overloaded the logical and bitwise operators to do both.

Other languages have them separated.

this

IINM, you have the same problem in C or C++.

and VBA probably builds on atop of C++

You will not really see a C++ coder normally using expression like if(<condition>==true) for that reason.

M.Doerner

Huh, the logical and bitwise operators in C and C++ are distinct.

this

in C, that is moot since there is no such thing as boolean data type. I am bit fuzzy how it's done in C++.

M.Doerner

C++ has an explicit bool data type.

this

given that VBA has no distinct logical operators, you'd be looking at writing If Not CBool(<condition>) Then to get the same behavior as C/C++'s if(!<condition>)

If <condition> = False Then has the same meaning & behavior but does with less words.

A small revision:

Public Sub testbits()
    Dim b As t1
    Dim i As t2
    Dim i2 As t2

    i.i = 256
    LSet b = i

    LSet i2 = b

    Debug.Print i.i, b.b, CInt(b.b), i2.i
End Sub

that does proves that the Boolean can store a value other than True/False, providing that you don't use VBA's usual way of assigning values.

Mathieu Guindon

7:48 PM

and for the last ~25 years I've been thinking the output of CInt(anyBoolean) could only ever be 0 or -1

M.Doerner

I do not see the boolean here.

this

Well, remember, the problem is that everything's a 0 or 1.

If you write to some random memory location, you will get ~~strange~~ undefined behavior.

Mathieu Guindon

Private Type t1
    b As Boolean
End Type

Private Type t2
    i As Integer
End Type

@M.Doerner ^ the types involved (assuming they haven't changed)

this

I assume that whenever you assign a value to a Boolean, or read from it, VBA obviously is smart enough to coerce it for you.

but CInt() is too naive for that.

FreeMan

and, that's what you get for ass-u-me-ing...

Mathieu Guindon

7:51 PM

what surprises me is that the coercion isn't happening at write-time

this

it should.

FreeMan

"it should happen" or "it should surprise him"?

this

Ok - X = Selection.Cells(1).FitText <- coerecion doesn't happen.

i have no idea what it's doing there.

Public Function IAmDumb() As Long
    IAmDumb = 1
End Function
Public Sub test2()
    Dim b As Boolean

    b = IAmDumb

    Debug.Print Not b, Not 1
End Sub

that doesn't repro.

Mathieu Guindon

right. looks like user code can't do it (other than with LSet)

this

Aha!

> True if Microsoft Word visually reduces the size of text typed into a cell so that it fits within the column width. Read/write Boolean.

Mathieu Guindon

7:58 PM

yes

this

so it returns a Boolean

Mathieu Guindon

yes, but one with 1 for true

this

therefore, if Word API sets it to 1.... well, that doesn't get coereced

let's prove that.

Mathieu Guindon

feel free to answer :)

this

Public Sub test3()
    Dim b As Boolean
    Dim b1 As t1
    Dim i1 As t2

    i1.i = 1
    LSet b1 = i1

    b = b1.b

    Debug.Print Not b
End Sub

That returns True

so, assignment of Boolean to another Boolean is not checked.

had it been a Long or Integer, then it would have gotten coerced by VBA

Mathieu Guindon

8:00 PM

now I wonder how many times in 25 years this bug was "discovered"

this

I've ran into it before. That's why I'm dogmatic about always writing conditions as If Foo Then and If Foo = False Then, never any other varieties.

Mathieu Guindon

I've written "If Foo = False Then is redundant, do If Not Foo Then instead" countless times all over CR & SO, for 7 years :(

2

this

at one point I thought as long it's converted into boolean, but I ran into another case where that is a dangerous assumption due to VBA's implicit here-let-me-manhandle-this-for-you-because-we-know-you-are-a-dumb-schmuck-and-I-know-better conversion.

That particular one, yes, should be apologized for. :)

but if it's If Foo Then, then no worries.

1 hour ago, by this

I need to remind myself that in the end, everything's a one or a zero.

Mathieu Guindon

there is no logic

(Jedi mind-trick hand motion)

this

lol

wait, I think I saw a 2.

Mathieu Guindon

8:04 PM

it's all bitwise. there's no logic. DONT LOOK FOR ANY LOGIC

poofs into a Force-ghost

dang I need caffeine

FreeMan

sounds like a perfect inspection candidate

this

FWIW:

0

A: VBA: Why would the Not operator stop working?

To add on to Cindy's excellent answer, I want to point out that while VBA normally has safeguards to coerce the values when assigning to a Boolean data type, this can be circumvented. Basically, if you write a random value to a memory address that's not yours, then you should expected undefined b...

#Protip: Don't twiddle the bits.

M.Doerner

8:27 PM

So, if I understand this correctly, the problem is that somebody at MS goofed up and forgot to send the return value generated in C++ through oleaut or similar before returning it as Boolean in VBA.

this

basically, yeah

Duga

8:43 PM

[rubberduck-vba/Rubberduck] IvenBach opened issue #5320: Find symbol hotkey catching when RD is not active

> Version 2.4.1.20935
OS: Microsoft Windows NT 10.0.18362.0, x64
Host Product: Microsoft Office 2013 x86
Host Version: 15.0.5023.1000
Host Executable: EXCEL.EXE

**Description**
This is an intermittent issue. When using the hotkey `Ctrl+T` to open a new browser tab, which is also the same as Find Symbol, RD is latching onto it. RD displays the Find Symbol dialog even though the VBA IDE isn't the active window.

**To Reproduce**
Steps to reproduce the behavior:
1. Have VBA IDE open in

[rubberduck-vba/Rubberduck] IvenBach added label bug to issue #5320: Find symbol hotkey catching when RD is not active

this

I think that's a known issue?

Mathieu Guindon

fixed, even. multiple times.

this

Oh? I thought it wasn't.

since it was a heisenbug

IvenBach

It's not fixed on my machine.

We building RD with 2017 still or 2019?

Mathieu Guindon

still 2017

will be 2017 until 2.5.0 is released

this

8:54 PM

speaking of which... what's stopping us form releasing 2.5?

said the guy who hasn't been contributing

Mathieu Guindon

we're waiting for some CS translations. other than that, ..I'd like the inspection results toolwindow scrollbars to behave and not wreck the bottom panel layout, but that's rather minor

M.Doerner

How about just moving the scroll viewer just around the grouping grid and pushing the change?

Mathieu Guindon

that should work, I think

Cyril

first time after opening a workbook a boolean function fails to pass "true". not sure what to do to fix that; after that first use, everything runs smooth

Mathieu Guindon

@Cyril what's the _Open handler doing?

Cyril

9:06 PM

...nothing?

i take it i need to instantiate the functions on load?

Mathieu Guindon

IDK, was a stab in the dark, I've no idea what code you've got! :)

Cyril

no worries; thought you had some like "i have that problem all the time" moments

Mathieu Guindon

#TIL a WPF keybinding can bind the WinKey as a modifier

Cyril

fuck yeah, was typiing to you exactly what i was intending to do and solved it

Mathieu Guindon

#rubberducking!

Cyril

9:17 PM

i made an array of my boolean variable states and generated BEFORE i populated the true scenarios

gotta love it

this

@MathieuGuindon I hope it doesn't let you bind it standalone without modifier. That would make for a evil application.

FreezePhoenix

Good evening!

@MathieuGuindon Explain how someone made a power function thats insanely faster than the builtin one, and, is entirely bitwise?

Mathieu Guindon

haven't done bit math in 20 years, ..I'm a bit rusty

BigBen

lol that's horrible

IvenBach

@MathieuGuindon Quick. What's derivative of x^(y^2+3*x)dx * cos(y^2 * 3x)dy???

Mathieu Guindon

9:30 PM

@BigBen I know, I know.. I'm here all week :)

IvenBach

Oh wait that's not bit math? :derp:

Mathieu Guindon

@IvenBach 42

Cyril

can a select case (switch) also function as a flowdown? first case met, use that, then proceed to check each case?

this

nope. VBA doesn't do fallthrough.

Cyril

copy; guess those will become if-statements per case. thanks!

IvenBach

9:37 PM

IIRC you can use Select Case to short circuit.

Cyril

?

IvenBach

VBA's lack of overloading irks me a bit.

this

yeah, you can, but that's not what Cyril is after.

Mathieu Guindon

@IvenBach yes but that's not what the question is :)

@IvenBach and once you get a language with overloads, you want overloads that return a different type, and you're back at square one

but yeah, it gets annoying :)

IvenBach

VBA with method overloading would simplify naming.

Mathieu Guindon

9:40 PM

case sensitivity would simplify naming too!

IvenBach

~.~ yes it would.

Mathieu Guindon

but, I hear ya

IvenBach

git diff is killing me because of that.

this

@MathieuGuindon you should talk to Jeff Atwood.

Mathieu Guindon

I should!

IvenBach

9:41 PM

git: Hey. All these changes happened.
Iven: That's cause they casing changed. I'm not concerned.
git: Hey. All these changes happened.
Iven: I know *casing* changed.
git: Hey. All these changes happened.
Iven: FML...

Mathieu Guindon

lol

this

git ain't that bright.

IvenBach

> That boy sure is dumb.

Cyril

alright, that's fixed... 169 logic gates; flowthrough/flowdown would have been amazing lol

this

idk if any other languages use those terms.

it's always been "fall through"

Cyril

9:48 PM

ahh, i misquoted you on "flowthrough"

this

and I suspect most modern languages doesn't let you do that, either.

Cyril

i had used it as flowdown, but that's related to fluid dynamics which is the closest memory i had of that function

this

Fall throughs were one good source of bugs

Cyril

<-- got learnt

ok, one of these days i'll get back to reading mat's blog about class modules; i feel like that would have helped me on this, but i'm a glutton for punishment...

off to clean the house before i have to get kids. night folks!

Mathieu Guindon

'night!

IvenBach

10:04 PM

Duck checking that git diff HEAD..FooBranch permits me to check the currently checked out head against a local branch named FooBranch.

the VBE - it's right for me

if im encountering a situation where my interface names are sounding (i think) like an inheritance structure is that a problem?

if that isnt enough for an answer i can detail lol

IvenBach

You have the names and code?

the VBE - it's right for me

code is a mess

names yes

one instance is something like IFormControl and IFormButtonControl

im not even sure if what im doing is right, which is why i asked

IvenBach

May need to wait for a bigger duck. I rarely use forms.

Just from IFormControl that comes off as a code smell (something that feels odd).

this

Exactly what do you intend to achieve?

Mathieu Guindon

10:16 PM

lol I just scored an "announcer" badge on meta.se and kept wondering why/when I shared a link to that. then I saw the comments..

Send them to gimmetehcodez.com! (link points to Mad Scientist's answer ;) — Mathieu Guindon May 1 '14 at 19:27

took 5.5 years, but I got 25 clicks on that link lol

the VBE - it's right for me

@this basically im trying to make my userforms as easy to edit/maintain as possible

when requirements change

this

See, I think that's wrong level.

the VBE - it's right for me

and have the interactivity behavior more aligned with modern windows

this

Because a form is already an interface

Mathieu Guindon

ish

this

10:18 PM

ditto for controls or anything that's from an external library, actually

Mathieu Guindon

any class is already an interface

this

in fact, everything in COM is interfaces.

Mathieu Guindon

^

this

What Mat said.

You want something more like....

Mathieu Guindon

that doesn't mean we shouldn't have interfaces in VBA though

this

10:19 PM

IInventoryDataEntry, or ISaleTransactionDataEntry or something....

Mathieu Guindon

that seems rather specific, compared to IFormControl, which looks nicely abstract

this

e.g. represent an action you need to perform and encapuslate that action.

But what will you do with a IFormControl, though?

Mathieu Guindon

#depends

thinking dynamic controls are involved?

the VBE - it's right for me

what exactly do you mean by dynamic

like add/remove at runtime?

Mathieu Guindon

created at run-time

yeah

this

10:20 PM

yes

the VBE - it's right for me

yeah that is one reason

that is actually

what caused me to use my first class module for a project

this

See, the name matters. If it was IRuntimeControl or IDynamicControl, that would be more clear, I think.

the VBE - it's right for me

but its not necessarily for that

this

IFormControl doesn't say much.

the VBE - it's right for me

its just meant to be any control on the form

this

10:22 PM

Which brings us back to the original question - why do you even need an abstraction over the controls themselves? They are already an interface.

If you want, you can use MSForm.Control to be more generic (right?)

the VBE - it's right for me

well you know how the controls in userforms are very "retro"

this

Use Access forms, then. :p

the VBE - it's right for me

some of them you can rescue with formatting, others you cant

this

So your'e writing your own UI framework?

the VBE - it's right for me

i guess?

ish

this

10:23 PM

or at least a theme thing.

whatever

the VBE - it's right for me

yeah

this

so I guess that also means a IFormControl could be actually several controls.

the VBE - it's right for me

yeah

this

to provide the look you want.

OK, so, why not IThemedControl?

the VBE - it's right for me

its not themed necessarily either

this

10:24 PM

IFancyPantControl

the VBE - it's right for me

there we go

this

the point being, you do want to have your names say something about what it does

so if I'm coming along I can see immediately why you're programming against a IFancyPantControl and not MSForms.Checkbox

Now.... I assume that you are trying to do multiple inheritance.

the VBE - it's right for me

i just have it at IFormControl because not all of the controls are fancy

i thought you cant do inheritance in vba?

like the textbox is the actual textbox

this

then I didn't understand your original question:

the VBE - it's right for me

okay so like

this

10:27 PM

14 mins ago, by the VBE - it's right for me

if im encountering a situation where my interface names are sounding (i think) like an inheritance structure is that a problem?

the VBE - it's right for me

oh

i said sounding because

this

It sounds to me you're saying thee's multiple level of inheritance, like datepicker -> data entry control -> control or something like that.

the VBE - it's right for me

IFormControl and IFormButtonControl

this

Ok, that's what I thought. there are multiple interfaces

the VBE - it's right for me

oh multiple interfaces?

yes

this

10:28 PM

so therefore a FormButton would need to implement both IFormControl and IformButtonControl

the VBE - it's right for me

yeah that is how i have it structured

but i wasnt sure if that was correct

this

that is OK.

You may want to consider providing a property to aid in casting, though.

as an example have the IFormButtonControl implement a Public Property Get Control As IFormControl

then the syntax becomes a bit nicer -- myButton.Control.<some method on IFormControl interface>

the VBE - it's right for me

oh wait you can do that?

that seems like it might be helpful in some cases

this

yeah but just so we're clear --- the FormButton still has to have both Implements IFormButtonControl and Implements IFormControl

the VBE - it's right for me

yes

this

10:31 PM

and implement both interfaces in its code module but yes, you can certainly add a Control As IFormControl to a "more derived" interfaces like IFormButtonControl

the VBE - it's right for me

it returns itself in the property

right?

this

correct

the VBE - it's right for me

okay that is

Duga

Hello from AWS!

4

I am working on becoming serverless!

the VBE - it's right for me

very helpful insight ty

this

10:32 PM

that way, you wouldn't have to do a Dim ib As IFormButtonControl then Dim ic As IformControl

and have them assigned to same object.

the VBE - it's right for me

yeah i was running into that problem too

when i needed to return something as one interface or the other

this

yes, the above works for going from more derived to less derived

the VBE - it's right for me

that isnt a precise way of saying it, but basically i had to make what seemed like extraneous declarations

this

I think as long you consistently always go from most derived to less derived, you will be fine.

the VBE - it's right for me

okay so clarify the derived thing

IFormButtonControl is more derived

and IFormControl is less?

this

10:34 PM

meaning, you start with the FormButton class itself, return a IFormButtonControl which can be then used to return a IFormControl where you need it.

Yes.

the VBE - it's right for me

okay got it

mostly at least

enough to start trying to apply it to what was getting me stuck

thank you :)

this

good luck!

the VBE - it's right for me

no promises i wont come back in a bit with more questions of course :3

IvenBach

10:51 PM

:derp: git remote add foo "\\localnetwork\...\.git" caused me far too long to catch that I needed to escape the '\` to accurately map the url.

:glare: escaping stuff escapes me how to do it properly.

Mathieu Guindon

@Duga got a hat yet? @SimonForsberg

(and the yearly notification count screenshot!)

ttgh

Simon Forsberg

@MathieuGuindon Even I don't have a hat yet.

Is there any easy hat that she can get?

Mathieu Guindon

"Warm Welcome", I suppose (it's last year's hats, so, same secret ones)

Simon Forsberg

@MathieuGuindon How to get it?

Mathieu Guindon

203

Q: Winter Bash 2018 Hat list

Here we go again, the Winter Bash is here and the hats are listed below. The list has the same format as always, there are only two answers: one for the secret hats, and one for the regular hats. The secret hat list will be updated as we learn them. Only edit the secret hat answer with definiti...

You could vote on an old post too

</mug>

IvenBach

11:09 PM

#TIL Left click to hold and drag a window. While dragging, wiggle the window back and forth. It'll minimize all the other windows but the one you're dragging. Release the mouse button and now that's the only window not minimized. If you don't want to actually minimize before letting go of the left click button press Esc to cancel the minimize.

Cyril

11:33 PM

Win key plus shift plus m will replace all minimized windows... or at least that was in win7

I have a sensitive mouse and accidentally wiggle-minimize often

Mathieu Guindon

11:50 PM

Hm, anyone else just got like a dozen+ announcer/booster badges? looks like a badge recalc task is under way

Transcript for