On 2017-08-01 10:00, Ken Dibble wrote:
A member of the VFP Team (I can't remember his name; he was the guy who "took out the slow parts" from various subsystems for VFP 8 and 9) wrote a blog article explaining that without the M. prefix, the system MUST compare every variable referenced to every field in the current work area every time the variable is accessed to determine whether the variable is a field name. He said that if the current work area contains a large number of fields, and the same variable is used over a large number of iterations in a tight loop, using the M. prefix makes a considerable difference in speed. He showed test results to demonstrate this.
I do a LOT of array iteration. So I began using the M. prefix for variables inside high-iteration tight loops. I noticed a slight speed increase.
However, I find the M. prefix ugly and distracting. I used it yesterday as a quick fix to demonstrate what the problem was. I will probably eventually rename the variable.
Ken
Very interesting...thanks for sharing that!