Checking conditions [IF ... THEN ... ELSE] performance

[cyrille de brébisson]

Hello,

You are correct. All parameters are evaluated FIRST and then the AND operation is 'calculated'.

a statement of the form
a AND b AND c
will be represented as an evaluation tree of the form (in LISP)
(AND a, AND(b, c))

It will cause a to be evaluated, then b, then c, then the b AND c will be calculated, and finally the a AND result of AND(b,c)...
You can check that by replacing a, b and c by function call that print something on the screen and looking at the print order.

This difears from C type programming languages which do have OR/AND operator short circuiting.

This feels correct for math operation, but it is true that it is not optimal from a programming performance point of view.

Cyrille