reset boolean.

reset boolean.

[Charlie_Brown]

	Hi to all,
		I have a question regarding a boolean statement. 
What I want to do is reset the statement to neither false nor true.
Is it possible?
	If anyone has an idea please help me out.
Thanks in advance.
Lyndon. 

 ____________________________________________________________________
|           ----====>>>> Lyndon Bernard Firmin <<<<====----          |
|--==>> The Royal Melbourne Institute of Techology, Australia <<==-- |
|     ----====>>>> email: firmin@yallara.cs.rmit.edu.au <<<<====---- | 
|____________________________________________________________________|       

Re: reset boolean.

[Robert Dewar]

Lyndon (Charlie-Brown) asks

"                I have a question regarding a boolean statement.
What I want to do is reset the statement to neither false nor true.
Is it possible?
        If anyone has an idea please help me out.
Thanks in advance."

That certainly is confused.
What is a boolean statement?
How can you possibly reset a statement to anything?

Well guessing game time, it soulds like you are asking if it is possible
to set a Boolean *variable* to a value other than True or False. The
answer is of course not.

However, you might want to define your own type

  type Extended_Boolean is (False, True, Neither);

of course if you have a value of this type you need to check explicitly
for it being equal to False or True, you can't just use the value 
directly in a Boolean context (like an if condition).

Re: reset boolean.

[Ken Price]

Charlie_Brown wrote:
> 
>         Hi to all,
>                 I have a question regarding a boolean statement.
> What I want to do is reset the statement to neither false nor true.
> Is it possible?
>         If anyone has an idea please help me out.
> Thanks in advance.
> Lyndon.
> 
>  ____________________________________________________________________
> |           ----====>>>> Lyndon Bernard Firmin <<<<====----          |
> |--==>> The Royal Melbourne Institute of Techology, Australia <<==-- |
> |     ----====>>>> email: firmin@yallara.cs.rmit.edu.au <<<<====---- |
> |____________________________________________________________________|

You really don't want a boolean value then.  Create another enumeration 
type to do your bidding...  The new enumeration type can contain the 
enumerations False, True, and Neither_True_Nor_False; the compiler will 
not confuse the True/False of Boolean and your True/False.

RE: reset boolean.

[Neil O'Brien]

On Sunday, August 18, 1996, Charlie_Brown wrote...
> 	Hi to all,
> 		I have a question regarding a boolean statement. 
> What I want to do is reset the statement to neither false nor true.
> Is it possible?
> 	If anyone has an idea please help me out.
> Thanks in advance.
> Lyndon. 
> 

It is a truth value, it can only have two possible settings true or false,
but you could declare your own enumeration type for example

my_bool is (true, false, neutral)

and use that instead - to be honest it seems a bit of a bizarre thing to
want to do, perhaps if you explained why you want it someone might be able
to suggest a better way.


--

=========================================================
Neil O'Brien			obrien@east.thomsoft.com
Customer Support		(617) 221 7320
Thomson Software Products


They're the wrong trousers Grommit, and they've gone wrong!

Re: reset boolean.

[Adam Beneschan]

Neil O'Brien <obrien@east.thomsoft.com> writes:
 >
 >On Sunday, August 18, 1996, Charlie_Brown wrote...
 >> 	Hi to all,
 >> 		I have a question regarding a boolean statement. 
 >> What I want to do is reset the statement to neither false nor true.
 >> Is it possible?
 >> 	If anyone has an idea please help me out.
 >> Thanks in advance.
 >> Lyndon. 
 >> 
 >
 >It is a truth value, it can only have two possible settings true or false,
 >but you could declare your own enumeration type for example
 >
 >my_bool is (true, false, neutral)
 >
 >and use that instead - to be honest it seems a bit of a bizarre thing to
 >want to do, perhaps if you explained why you want it someone might be able
 >to suggest a better way.
 >

I've never understood these three-way Booleans.  To be complete,
shouldn't there be a lot more values in the enumeration type?  E.g.:

   type My_Bool is (True, False, Maybe, True_And_False, It_Depends,
                    Dont_Know, Dont_Care, None_Of_Your_Business,
                    All_Of_The_Above);

:)

                                -- Adam

Re: reset boolean.

[Larry Hazel]

Adam Beneschan wrote:
[snip]
> 
> I've never understood these three-way Booleans.  To be complete,
> shouldn't there be a lot more values in the enumeration type?  E.g.:
> 
>    type My_Bool is (True, False, Maybe, True_And_False, It_Depends,
>                     Dont_Know, Dont_Care, None_Of_Your_Business,
>                     All_Of_The_Above);
> 


How about

   type Illogical is (Maybe, Maybe_Not);

-- Larry Hazel => Larry.H.Hazel@cpmx.saic.com (205) 876-4509
-- I try to stay above C level,  I get C sick.
-- Team Ada & Team OS/2

Re: reset boolean.

[Ian Ward]

In article fc899dc0@fielding.east.alsys.com, Neil O'Brien <obrien@east.thomsoft.com> () writes:
>
>On Sunday, August 18, 1996, Charlie_Brown wrote...
>> 	Hi to all,
>> 		I have a question regarding a boolean statement. 

snip...

>
>It is a truth value, it can only have two possible settings true or false,
>but you could declare your own enumeration type for example

Neil, you forgot one instance. Ada can define the optional very_true, 
almost_true, and true_enough for use in political and pension advisors
software. :-)

(One must not forget the "/" operator which for intel processors can be 
overloaded with "?/"; Plus, finally, the what_do_you_think_it_is, for
artistic and child centred learning software.)

Best regards,
Ian




---
Ian Ward's opinions only : wardi@rsd.bel.alcatel.be