Re: Operation order in expressions

[John Yeung <gallium.arsenide@xxxxxxxxx>]

Thanks for the recap, Vern. Just goes to show that it's important to
pay attention to these things, especially since different languages
have different operator precedence. (For example, RPG goes against my
intuition with regard to exponentiation. I expect it to be ahead of
unary sign, because that's how it is in standard algebraic notation.)

IMO, it's not a bad practice to use parens more often than necessary.

For languages that have it, "NOT IN" is a single operator, that
happens to be written as two words.

John Y.


On Thu, Aug 17, 2023 at 7:03 AM Vern Hamberg via RPG400-L
<rpg400-l@xxxxxxxxxxxxxxxxxx> wrote:
> The following list indicates the precedence of operations from highest
> to lowest:
> 1. ()
> 2. Built-in functions, user-defined functions
> 3. unary +, unary -, NOT
> 4. **
> 5. *, /
> 6. binary +, binary -
> 7. =, <>, >, >=, <, <=, IN
> 8. AND
> 9. OR
>
> Higher precedence are done before lower. Operations at the same level
> are done left to right, except **, it says.
>
> BTW, an expression like this, putting NOT with IN -
>
>       IF FV(i).data_type NOT IN %list('NUMERIC' :'CHAR');
>
> is not valid in RPG, while it IS valid in SQL, IIRC.