(true = 1) returns false?

[Evertjan.]

Re: (true = 1) returns false?

Jason wrote on 06 jun 2006 in microsoft.publi c.inetserver.as p.general:[color=blue]
> "roger" <mothland@btope nworld.com> wrote in message[color=green]
>>
>>
>> Perhaps I am not understanding the problem
>>
>> dim b
>>
>> b = 1
>> if b then Response.Write "true = 1"
>> if b = true then Response.Write "but this doesn't work"
>>
>> gives me the result...
>>
>> true = 1
>>
>> Isn't that what you want?
>>[/color]
>
> Yes. That's exactly what I want, but your example doesn't work that
> way for me when I do it. For me, b = 0 evaluates to false, b = -1
> evaluates to true, and if b equals any other number, then b is neither
> true nor false. Are you sure that code works for you? I mean, did you
> test it? Because if it does, I would be interested to know why it
> works for you and not for me.[/color]

Then why use the internal evaluation?

Using your definition:

if b = 0 then
b = "is false"
elseif b=-1 then
b = "is true"
else
b = "is neither"
end if



--
Evertjan.
The Netherlands.
(Please change the x'es to dots in my emailaddress)

[Jason]

Re: (true = 1) returns false?


"Evertjan." <exjxw.hannivoo rt@interxnl.net > wrote in message
news:Xns97DA611 DAA9C9eejj99@19 4.109.133.242.. .[color=blue][color=green]
>> works for you and not for me.[/color]
>
> Then why use the internal evaluation?
>
> Using your definition:
>
> if b = 0 then
> b = "is false"
> elseif b=-1 then
> b = "is true"
> else
> b = "is neither"
> end if
>[/color]
Yeah, I could do that....but I was looking for a solution that didn't
involve changing my code every place I used 'if b = true then...'

There is no solution that I am aware of so I did change my code from 'if
b=true then...' to 'if CBool(b) = true then...' in every spot.

[Evertjan.]

Re: (true = 1) returns false?

Jason wrote on 06 jun 2006 in microsoft.publi c.inetserver.as p.general:[color=blue]
> "Evertjan." <exjxw.hannivoo rt@interxnl.net > wrote in message[color=green][color=darkred]
>>> works for you and not for me.[/color]
>>
>> Then why use the internal evaluation?
>>
>> Using your definition:
>>
>> if b = 0 then
>> b = "is false"
>> elseif b=-1 then
>> b = "is true"
>> else
>> b = "is neither"
>> end if
>>[/color]
> Yeah, I could do that....but I was looking for a solution that didn't
> involve changing my code every place I used 'if b = true then...'
>
> There is no solution that I am aware of so I did change my code from
> 'if b=true then...' to 'if CBool(b) = true then...' in every spot.[/color]

Since if then tests for true/false itself,
I would not expect any difference in behavur between:

if b = true then

and

if b then

however,
if you want to test for "true", "false" and "neither",
my above code remains necassary, IMHO.


--
Evertjan.
The Netherlands.
(Please change the x'es to dots in my emailaddress)

[Jason]

Re: (true = 1) returns false?

>[color=blue]
> Since if then tests for true/false itself,
> I would not expect any difference in behavur between:
>
> if b = true then
>
> and
>
> if b then
>
> however,
> if you want to test for "true", "false" and "neither",
> my above code remains necassary, IMHO.
>[/color]
I don't think you understand the problem. ASP defines 0 as false and -1 as
true, and everything else is neither. I wanted a way to make ASP define 1
also as true, but we couldn't come up with one except to change code
everywhere I needed that extra functionality.

[Evertjan.]

Re: (true = 1) returns false?

Jason wrote on 06 jun 2006 in microsoft.publi c.inetserver.as p.general:
[color=blue][color=green]
>> if you want to test for "true", "false" and "neither",
>> my above code remains necassary, IMHO.
>>[/color]
> I don't think you understand the problem.[/color]

True.
[color=blue]
> ASP defines 0 as false and
> -1 as true, and everything else is neither.[/color]

Not true.

==============

ASP is just the platform, and does not define.

==============

ASP-VBscript does boolean TEST 0 as false and all other as true.
[You could call that "define"]

if 7 then response.write "TRUE"

if NOT 0 then response.write "FALSE"

VBscript does translate in a FORMULA true as -1, and false as 0

response.write true ' shows True

response.write 7 + true ' shows 6

response.write 7 + false ' shows 7

===============

ASP-JScript TESTS [boolean] 0 as false and other numbers as true,

if (7) response.write( 'TRUE' );

if (! 0) response.write( 'FALSE' );

and does translate in a FORMULA true as 1, and false as 0

response.write( 7 + true ); // 8

[color=blue]
> I wanted a way to make
> ASP define 1 also as true, but we couldn't come up with one except to
> change code everywhere I needed that extra functionality.
>[/color]



--
Evertjan.
The Netherlands.
(Please change the x'es to dots in my emailaddress)

[Bob Barrows [MVP]]

Re: (true = 1) returns false?

Jason wrote:[color=blue][color=green]
>>[/color]
> I don't think you understand the problem. ASP defines 0 as false and
> -1 as true, and everything else is neither.[/color]

No, not quite. If an expression evaluates to 0, it is False. All other
results are True*. Again, try:

<%
Response.Write CBool(-1)
Response.Write CBool(0)
Response.Write CBool(1)
Response.Write CBool(2)

%>
Here is the result I get from this:
TrueFalseTrueTr ue
So you see that CBool(2) resulted in True. In fact, the only one that
resulted in False was 0.

In fact, try this:
<%
if (1+3) then
Response.Write "<br>true"
else
Response.Write "<br>false"
end if

s="abcd"
Response.Write "<BR>" & instr(s,"c")
if instr(s,"c") then
Response.Write "<BR>c is in abcd"
else
Response.Write "<BR>c is not in abcd"
end if
%>


This is the real reason both Yes/No values from Access and bit values
from SQL Server work well in vbscript/vb.
I'm still not clear about why your boolean values from MySQL aren't
working the same way.

Bob Barrows

*I realize I mistakenly said the reverse of this in my earlier message -
my apologies.
--
Microsoft MVP -- ASP/ASP.NET
Please reply to the newsgroup. The email account listed in my From
header is my spam trap, so I don't check it very often. You will get a
quicker response by posting to the newsgroup.

[Mike Brind]

Re: (true = 1) returns false?


Bob Barrows [MVP] wrote:[color=blue]
> Jason wrote:[color=green][color=darkred]
> >>[/color]
> > I don't think you understand the problem. ASP defines 0 as false and
> > -1 as true, and everything else is neither.[/color]
>
> No, not quite. If an expression evaluates to 0, it is False. All other
> results are True*.[/color]

Interestingly, this is exactly the same in MySQL:
(See BOOL,BOOLEAN subhead)

http://dev.mysql.com/doc/refman/5.0/en/numeric-type-overview.html

--
Mike Brind

[roger]

Re: (true = 1) returns false?


"Jason" <bigwheels16 hotmail> wrote in message
news:3sidnRgXm8 8gkxjZnZ2dnUVZ_ smdnZ2d@comcast .com...
[color=blue]
> Yes. That's exactly what I want, but your example doesn't work that way[/color]
for[color=blue]
> me when I do it. For me, b = 0 evaluates to false, b = -1 evaluates to
> true, and if b equals any other number, then b is neither true nor false.
> Are you sure that code works for you? I mean, did you test it? Because[/color]
if[color=blue]
> it does, I would be interested to know why it works for you and not for[/color]
me.

Very strange. And yes I did test it.

"if b then"
should test whether b is non-zero.

and

"if b = true then"
should test whether b is identical to the definition of the keyword "true",
which in VBScript is -1.

I remain mystified why this doesn't work for you.

--
roger

[Anthony Jones]

Re: (true = 1) returns false?


"Bob Barrows [MVP]" <reb01501@NOyah oo.SPAMcom> wrote in message
news:u9Jaz4aiGH A.1508@TK2MSFTN GP04.phx.gbl...[color=blue]
> Jason wrote:[color=green][color=darkred]
> >>[/color]
> > I don't think you understand the problem. ASP defines 0 as false and
> > -1 as true, and everything else is neither.[/color]
>
> No, not quite. If an expression evaluates to 0, it is False. All other
> results are True*. Again, try:
>
> <%
> Response.Write CBool(-1)
> Response.Write CBool(0)
> Response.Write CBool(1)
> Response.Write CBool(2)
>
> %>
> Here is the result I get from this:
> TrueFalseTrueTr ue
> So you see that CBool(2) resulted in True. In fact, the only one that
> resulted in False was 0.
>
> In fact, try this:
> <%
> if (1+3) then
> Response.Write "<br>true"
> else
> Response.Write "<br>false"
> end if
>
> s="abcd"
> Response.Write "<BR>" & instr(s,"c")
> if instr(s,"c") then
> Response.Write "<BR>c is in abcd"
> else
> Response.Write "<BR>c is not in abcd"
> end if
> %>
>
>
> This is the real reason both Yes/No values from Access and bit values
> from SQL Server work well in vbscript/vb.
> I'm still not clear about why your boolean values from MySQL aren't
> working the same way.[/color]

Actually the reason it works is that if you check the field type property it
is set to adBoolean (11) that is boolean.
Since the value property is a variant it will contain either -1 for True or
0 for False.

I suspect the MySQL isn't using this adBoolean (probably adUnsignedTinyI nt
or some such) and therefore the value comes through as 1


[color=blue]
>
> Bob Barrows
>
> *I realize I mistakenly said the reverse of this in my earlier message -
> my apologies.
> --
> Microsoft MVP -- ASP/ASP.NET
> Please reply to the newsgroup. The email account listed in my From
> header is my spam trap, so I don't check it very often. You will get a
> quicker response by posting to the newsgroup.
>
>[/color]

[Bob Barrows [MVP]]

Re: (true = 1) returns false?

Anthony Jones wrote:[color=blue][color=green]
>> This is the real reason both Yes/No values from Access and bit values
>> from SQL Server work well in vbscript/vb.
>> I'm still not clear about why your boolean values from MySQL aren't
>> working the same way.[/color]
>
> Actually the reason it works is that if you check the field type
> property it is set to adBoolean (11) that is boolean.
> Since the value property is a variant it will contain either -1 for
> True or 0 for False.
>
> I suspect the MySQL isn't using this adBoolean (probably
> adUnsignedTinyI nt or some such) and therefore the value comes through
> as 1
>[/color]
Yes, you're probably correct.
--
Microsoft MVP -- ASP/ASP.NET
Please reply to the newsgroup. The email account listed in my From
header is my spam trap, so I don't check it very often. You will get a
quicker response by posting to the newsgroup.

[Jason]

Re: (true = 1) returns false?

"Bob Barrows [MVP]" <reb01501@NOyah oo.SPAMcom> wrote in message
news:u9Jaz4aiGH A.1508@TK2MSFTN GP04.phx.gbl...[color=blue]
>
> This is the real reason both Yes/No values from Access and bit values
> from SQL Server work well in vbscript/vb.
> I'm still not clear about why your boolean values from MySQL aren't
> working the same way.
>
> Bob Barrows
>[/color]
I'm not clear why either. :)

--jason

[Jason]

Re: (true = 1) returns false? -- THE ANSWER

"Bob Barrows [MVP]" <reb01501@NOyah oo.SPAMcom> wrote in message
news:ebBpHBjiGH A.3496@TK2MSFTN GP02.phx.gbl...[color=blue]
> Anthony Jones wrote:[color=green][color=darkred]
>>> This is the real reason both Yes/No values from Access and bit values
>>> from SQL Server work well in vbscript/vb.
>>> I'm still not clear about why your boolean values from MySQL aren't
>>> working the same way.[/color]
>>
>> Actually the reason it works is that if you check the field type
>> property it is set to adBoolean (11) that is boolean.
>> Since the value property is a variant it will contain either -1 for
>> True or 0 for False.
>>
>> I suspect the MySQL isn't using this adBoolean (probably
>> adUnsignedTinyI nt or some such) and therefore the value comes through
>> as 1
>>[/color]
> Yes, you're probably correct.
> --
> Microsoft MVP -- ASP/ASP.NET
> Please reply to the newsgroup. The email account listed in my From
> header is my spam trap, so I don't check it very often. You will get a
> quicker response by posting to the newsgroup.
>[/color]
Ok, I figured out why we're having this problem. And it's kind of my bad,
kind of. :P I assumed it would work the same way it does in C++, but it
doesn't.

My if statements look like this:

<%
if rsobj("column") = true then
%>

and that fails, but if I change them to this:

<%
if rsobj("colum") then
%>

then it works.

It appears that true is just an alias for -1. So ASP (using vbscript) as a
language defines true as anything except false, and defines false as zero,
but the keyword true is only defined as -1.

I can't say I am pleased with this, but I am pleased with knowing why.

--jason

[Jason]

Re: (true = 1) returns false?

"Jason" <bigwheels16 hotmail> wrote in message
news:DtudnU-1nsykihrZnZ2dnU VZ_s6dnZ2d@comc ast.com...[color=blue]
> "Bob Barrows [MVP]" <reb01501@NOyah oo.SPAMcom> wrote in message
> news:u9Jaz4aiGH A.1508@TK2MSFTN GP04.phx.gbl...[color=green]
>>
>> This is the real reason both Yes/No values from Access and bit values
>> from SQL Server work well in vbscript/vb.
>> I'm still not clear about why your boolean values from MySQL aren't
>> working the same way.
>>
>> Bob Barrows
>>[/color]
> I'm not clear why either. :)
>
> --jason[/color]
I posted this just before I discovered why.

--jason

[Anthony Jones]

Re: (true = 1) returns false? -- THE ANSWER


"Jason" <bigwheels16 hotmail> wrote in message
news:z4mdnQX7S9 gugBrZnZ2dnUVZ_ t2dnZ2d@comcast .com...[color=blue]
> "Bob Barrows [MVP]" <reb01501@NOyah oo.SPAMcom> wrote in message
> news:ebBpHBjiGH A.3496@TK2MSFTN GP02.phx.gbl...[color=green]
> > Anthony Jones wrote:[color=darkred]
> >>> This is the real reason both Yes/No values from Access and bit values
> >>> from SQL Server work well in vbscript/vb.
> >>> I'm still not clear about why your boolean values from MySQL aren't
> >>> working the same way.
> >>
> >> Actually the reason it works is that if you check the field type
> >> property it is set to adBoolean (11) that is boolean.
> >> Since the value property is a variant it will contain either -1 for
> >> True or 0 for False.
> >>
> >> I suspect the MySQL isn't using this adBoolean (probably
> >> adUnsignedTinyI nt or some such) and therefore the value comes through
> >> as 1
> >>[/color]
> > Yes, you're probably correct.
> > --
> > Microsoft MVP -- ASP/ASP.NET
> > Please reply to the newsgroup. The email account listed in my From
> > header is my spam trap, so I don't check it very often. You will get a
> > quicker response by posting to the newsgroup.
> >[/color]
> Ok, I figured out why we're having this problem. And it's kind of my bad,
> kind of. :P I assumed it would work the same way it does in C++, but it
> doesn't.
>
> My if statements look like this:
>
> <%
> if rsobj("column") = true then
> %>
>
> and that fails, but if I change them to this:
>
> <%
> if rsobj("colum") then
> %>
>
> then it works.
>
> It appears that true is just an alias for -1. So ASP (using vbscript) as[/color]
a[color=blue]
> language defines true as anything except false, and defines false as zero,
> but the keyword true is only defined as -1.
>
> I can't say I am pleased with this, but I am pleased with knowing why.
>[/color]


Take this C++ :-

if (5 == true)
// 5 is equal to true this doesn't happen
else
// 5 is not equal to true this happens


However things are different if you do this:-

if (1 == true)
// 1 is equal to true this does happen
else
// 1 is not equal to true this doesn't happen

or this:-

if (5)
// This always happens
else
// This never happens


In C/C++ (as is the same with VB/Script) when a boolean type and a numeric
type are either side of an operand it is the boolean which is coerced to a
numeric. However the C/C++ true is an 'alias' for 1 whereas in
VB/Script/COM a true is -1. The reason -1 was chosen is that VB does not
differentiate between bitwise and logical operators (e.g. & or && in C)
it only has bitwise operators (and, or, not).

It seems you have two problems.

1) using 'if x = true then' forces the true to be coerced to a numeric and
then a comparison is made and then a branch is made accordingly. Whereas
'if x Then' simply branches to 'then' on non-zero and 'else' on zero.

2) rsobj("column") isn't a boolean type but some kind of numeric type
(although I have found some interface declare a COM interface having a
boolean parameter or member but actually use 1 instead of -1 but that is
poor implementation) .

Frankly stop doing this x = true and be aware that all apparently logical
operators in VB are in fact bitwise

[color=blue]
> --jason
>
>[/color]

[Bob Barrows [MVP]]

Re: (true = 1) returns false? -- THE ANSWER

Anthony Jones wrote:[color=blue]
> 2) rsobj("column") isn't a boolean type but some kind of numeric type
> (although I have found some interface declare a COM interface having a
> boolean parameter or member but actually use 1 instead of -1 but that
> is poor implementation) .
>
> Frankly stop doing this x = true and be aware that all apparently
> logical operators in VB are in fact bitwise
>
>[/color]
An alternative would be to coerce the MySQL boolean trues to -1, perhaps
using a view with a calculated column.

--
Microsoft MVP - ASP/ASP.NET
Please reply to the newsgroup. This email account is my spam trap so I
don't check it very often. If you must reply off-line, then remove the
"NO SPAM"