Re: "Nasty" bug
- Posted by lesterb Feb 24, 2019
- 2097 views
Hi Irv,
I had a look at this and discovered 2 things...
1. Phix gets it right.
2. There's a note in the 3.1.1 documentation about exactly this case. It reads..
The expressions are evaluated, and any subscripting is performed, from left to right. It is possible to have function calls in the right-hand-side expression, or in any of the left-hand-side expressions. If a function call has the side-effect of modifying the lhs_var, it is not defined whether those changes will appear in the final value of the lhs_var, once the assignment has been completed. To be sure about what is going to happen, perform the function call in a separate statement, i.e. do not try to modify the lhs_var in two different ways in the same statement. Where there are no left-hand-side subscripts, you can always assume that the final value of the lhs_var will be the value of rhs_expr, regardless of any side-effects that may have changed lhs_var.
Les
