Boolean expression evaluation routine required

[Killer42]

...This would be a cool routine in inself if it worked. Might be useful for making sense of complex statements by translating them into a more easy to read format.

That sounds like a worthy goal. I've seen some mighty complex IF statements at times. (Probably guilty of writing some pretty nasty ones, too.)

[JosAH]

@Railgunner: if you want to minimize boolean expressions, as in e.g.
(A and B) or ((not A) and B) ---> B have a look at the Quine McCluskey
simplification algorithm.

kind regards,

Jos

[luke14free]

seriously i didn't undersstand why is my code wrong...:(
could you repeat it to me?
how ever couldn't you do something like that

IF (A=2 AND (B=3 OR C=4)) OR C=4

now lets split the condition(suppo se that we have taken out the if yes so we just have (A=2 AND (B=3 OR C=4)) OR C=4 with the separator '(' and ')' and take out them(just the initual and fianl onem so we get A=2 AND (B=3 OR C=4)-->we take what is in the first ()
now lets do a while that say: continue this procedure until there are no other panens inside our code.in our case we get B=3 OR C=4...lets pass this condition and suppose that you get TRUE

so some it up...(A=2 AND (B=3 OR C=4)) OR C=4-->A=2 AND (B=3 OR C=4)-->B=3 OR C=4-->TRUE

now rewind... we know that the most internal condition is TRUE lets take out the condition and put TRUE in his place...we get
(A=2 AND TRUE) OR C=4

our while cicle sees another parens so(suppose that A is 2):
(A=2 AND TRUE) OR C=4-->A=2 AND TRUE-->TRUE

and so you have:

TRUE OR C=4

you exit from the while because there are no longer parens...

the you just need to pass the C=4 to an IF cicle..
suppose that returns TRUE

TRUE OR TRUE

pass into another IF

TRUE

so thats the routine that i am going to build...do you think that would be finally right?

best regards

[Motoma]

Hmm, only one thing, if you get something like this
a=2

if 'a = 2' is True etcetra...

then you take the string condition that is 'a = 2'...you can split it and you get:
'a','=','2'...f or the = there is no problem, you can do a series of if cases and you say if sing= '=' elif sign='<'... and so on.
for the number is very easy because you get the int value from a string..
but now you have to get back from a letter or a word (that in our case is 'a') to a var that is really different from a (without quotes!)
so your expression becames:

the word 'a' is equal to 2

and you'll get false... because we aren't talking about the var!

however thanks for the explanation!

This is only a problem if you don't account for it in the language. You would need to create a data structure for holding your variable assignments: a hash table should do quite well for mapping variable names to their values. The function which does the processing on a node wouldn't be a direct mapping of strings to logical operators, rather the booleanop() from my pseudo-code was merely a high level abstraction of the process.

[luke14free]

This is only a problem if you don't account for it in the language. You would need to create a data structure for holding your variable assignments: a hash table should do quite well for mapping variable names to their values. The function which does the processing on a node wouldn't be a direct mapping of strings to logical operators, rather the booleanop() from my pseudo-code was merely a high level abstraction of the process.

and you think that this would be done in basic for just 500$? eheh,,,i am not helping railgunner for moneys...but its a quite difficult to do it...i could try to do it in another language such as c python or perl...but in basic is just for people who dont need to reach those levels...correc t me if i am wrong, but i think its quite impossible...we should find another solution,isnt it motoba?
however i am valutating the possibility to create a code for hash datas...:)
one question for railgunner: do you sleep an night or you just code?eheh :P

[Motoma]

No, I don't; in fact, a few posts ago I mentioned that it would be a difficult task to coerce someone into building this system in a rudimentary language such as BASIC or COBOL for such a low price.

and you think that this would be done in basic for just 500$?

[Railgunner]

and you think that this would be done in basic for just 500$? eheh,,,i am not helping railgunner for moneys...but its a quite difficult to do it...i could try to do it in another language such as c python or perl...but in basic is just for people who dont need to reach those levels...correc t me if i am wrong, but i think its quite impossible...we should find another solution,isnt it motoba?
however i am valutating the possibility to create a code for hash datas...:)
one question for railgunner: do you sleep an night or you just code?eheh :P

Well, i've managed to write an interpreter than can execute IF/ELSE-IF logic
(minus the parens) in what amounts to COBOL so anythings possible:)

I really didn't expect someone to write the routine from scratch for $500. I was hoping that someone might know where to find an example of such a routine in VB and the reward was for finding it:)

I did actually find the source for a basic interpreter here. The author said he wrote it in a "an hour or two". I hope he's not telling the truth because that would make me feel really dumb.

http://www.sics.se/~adam/ubasic/

I've been looking at it but it's written in C. I guess I could learn C but I was really
hoping I wouldn't have to.

[luke14free]

I've been looking at it but it's written in C. I guess I could learn C but I was really
hoping I wouldn't have to.

So dont learn it...!
i ve found an old basic compiler/compiler written in basic! i am working to get the source code!! and you'll have what you needed!
just wait 2/3 days and i'll give you what you needed
do you prefer all the sources or just the one for the if/else use?

[luke14free]

Never mean what I wrote
you code is here!
thanks to matoma who has gave me the various explainations.. .the code posted is a complex Tree Function...see my post here for more details...

http://www.thescripts.com/forum/showthread.php?p=2514176#post2514176