Re: Operation Precedence questions

Dan, I think you've missed the implicit aspects of all this.

                 A AND B  AND C
is logically    (A AND B) AND C
which is also  ((A AND B) AND C)

Additionally, an indicator field is actually an expression of whether the
indicator is on.

IF *IN90 is actually IF (*IN90 = '1')

Therefore, your expression

          A AND B AND X < 10

is actually

      (((A = '1') AND (B = '1')) AND (X < 10))

the program evaluates if the inner left expression (A = '1') is true,
if so, then evaluates if the inner right expression (B = '1') is true,
if so, then if the middle left expression (A = '1' AND B = '1') is true.
if so, then if the middle right expression (X < 10) is true,
if so, finally if the expression as whole is true.

Once you supply the "missing" implicit aspects, you'll see that the rules
DO apply.

Jim



                                                                                
               
                    Dan                                                         
               
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                    03/20/2003 02:18 PM                                         
               
                    Please respond to                                           
               
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Hi Barbara,

Now I *know* I'm going to be set straight on this!  However, never content
to let the highest
authority on a given subject leave a question unanswered <g>...

Your example does not include the use of the =, <>, >, >=, <, <= operators.
What if your example
were thus:
    A AND B AND X < 10

According to the rules of Operation Precedence, the X < 10 should be
evaluated before A AND B.

Where am I going wrong on this?

- Dan

--- Barbara Morris <bmorris@xxxxxxxxxx> wrote:
<snip>
> Dan, in the expression A AND B AND C, there are actually two AND
> expressions:
>    A AND B
>    "value of A AND B" AND C
> For the first one, if A is false, B isn't evaluated.  For the second
> one, if "value of A AND B" is false, C isn't evaluated.

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