topic Re: a syntax question in Libraries & objects

a syntax question

Anonymous — Mon, 15 Aug 2005 02:33:13 GMT

Hello,
Where "lmtr" is an angle type parameter,
is the expression "if 0<lmtr<180 then ...do something"
a valid substitute for and has the same meaning as the expression
"if lmtr >0 AND lmtr<180 then...do something" ?
Thank you,
Peter Devlin

Re: a syntax question

Frank Beister — Mon, 15 Aug 2005 06:33:29 GMT

I don't think so, because the operators =,<,> are boolean operators and are not a defining statement as RANGE in VALUES.

AC will first calculate 0<lmtr with the result 0 or 1 and then result<180.

0<lmtr<180 = ( (0<lmtr) <180)

lmtr=-10 -> (0<lmtr) =0 -> 0<180=1 -> result true
lmtr=45 -> (0<lmtr) =1 -> 1<180=1 -> result true
lmtr=210 -> (0<lmtr) =0 -> 0<180=1 -> result true

But (0<lmtr) * (lmtr<180) should work:

lmtr=-10 -> 0*1=0 -> result false
lmtr=45 -> 1*1=1 -> result true
lmtr=210 -> 1*0=0 -> result false

or ABS(lmtr-90)<90

But thats all not more readable than (0<lmtr) AND (lmtr<180)

Re: a syntax question

Anonymous — Mon, 15 Aug 2005 19:31:03 GMT

Frank,
Thank you very much for your reply.
Very concisely put and answers my question.
Your final statement makes me curious about something.
You wrote: "But thats all not more readable than (0<lmtr) AND (lmtr<180)"
Why are the parentheses necessary ?

Thank you,
Peter Devlin

Re: a syntax question

Frank Beister — Mon, 15 Aug 2005 22:29:15 GMT

You wrote: "But thats all not more readable than (0<lmtr) AND (lmtr<180)"
Why are the parentheses necessary ?

They aren', but I like to see the terms visual separated and sometimes I add some clearing parentheses. You are right, 0<lmtr AND lmtr<180 comes to same result. It seems the order is:

^
*/
+-
<>=
AND OR

NOT(), because it's a function, does not need to be set in this order.

Re: a syntax question

Anonymous — Mon, 15 Aug 2005 23:53:28 GMT

Thanks for the explanation Frank.
Peter Devlin