----- Original Message -----
Sent: Tuesday, October 25, 2005 9:24
PM
Subject: RE: [Hardhats-members] M
statements
A visual look at the first line, parsing and
calculating the truth value of each _expression_ in the string,
then substituting that value in the next
calculation:
EHR>W X
0115LV
EHR>W $L(X)
6
EHR>W 6>30
0
EHR>W
0!$L(X)
1
EHR>W 1<6
1
which is the truth value, so write "Done"
Now,
the second line:
EHR>W X
0115LV
EHR>W $L(X)
6
EHR>W
6!$L(X)
1
EHR>W 1>30
0
which is false - so don't write "Done"
Duncan Pringle,
PMP
perotsystems
813.371.7284 (office)
813.891.6138 (fax)
727.244.8008 (cell)
AIM: imdpringle
Email: [EMAIL PROTECTED]
Maybe a simpler explanation is this:
The length of X is 6, so when M does the logic, is x
greater than 30? No, then it gets an or, this is where the logic breaks.
The or get evaluated as the length of X (the less than 6 is excluded),
therefore it is true.
Robert DeWayne
Senior Consultant
Daou Systems, Inc.
P: (317) 616-4745 C:(317)
727-7477
Usha,
M is very strict about interpreting
logic sequences and about evaluating each separate element and operator.
In your first statement M does something like this:
$L(X) is 6, is 6 greater than 30? No, so that
evaluates False or 0. Now OR that with $L(X) which is 6, giving 0 OR
6. 0 is False, 6 is True, so result is True or 1. Now is 1 less
than 6? Yes, so whole logic equation evaluates as True and we Write
"Done.
The solution to making it perform as
intended is to use parentheses:
>S X="0115LV" I ($L(X)>30)!($L(X)<6) W
"DONE"
For the sake of pure logic, you don't
need the parentheses around $L(X)>30 but using them helps clarify
the intent to the next programmer that reads it.
tjh
Hi
Just wondering what brings in the difference in
output of the following statements
EHR 3f0>S X="0115LV" I $L(X)>30!$L(X)<6
W "DONE"
DONE
EHR 3f0>S X="0115LV" I $L(X)<6!$L(X)>30 W
"DONE"
EHR 3f0>
Why does the respond in the way it is?
Usha
