The way calculate is written, this evaluates (- (* (+ 4 4) (+ 4 4)) (* (+ 4 4) (+ 4 4))), which is 0. I don't know what you expect, but let's take a look at tracing (SO> is the repl prompt):
SO> (trace evaluate calculate)
(EVALUATE CALCULATE)
SO> (calculate '(- * + 4 3 2 5))
0: (SO::CALCULATE (- * + 4 3 2 5))
1: (SO::CALCULATE (* + 4 3 2 5))
2: (SO::CALCULATE (+ 4 3 2 5))
3: (SO::CALCULATE (4 3 2 5))
3: CALCULATE returned 4
3: (SO::CALCULATE (4 3 2 5))
3: CALCULATE returned 4
3: (SO::EVALUATE + 4 4)
3: EVALUATE returned 8
2: CALCULATE returned 8
2: (SO::CALCULATE (+ 4 3 2 5))
3: (SO::CALCULATE (4 3 2 5))
3: CALCULATE returned 4
3: (SO::CALCULATE (4 3 2 5))
3: CALCULATE returned 4
3: (SO::EVALUATE + 4 4)
3: EVALUATE returned 8
2: CALCULATE returned 8
2: (SO::EVALUATE * 8 8)
2: EVALUATE returned 64
1: CALCULATE returned 64
1: (SO::CALCULATE (* + 4 3 2 5))
2: (SO::CALCULATE (+ 4 3 2 5))
3: (SO::CALCULATE (4 3 2 5))
3: CALCULATE returned 4
3: (SO::CALCULATE (4 3 2 5))
3: CALCULATE returned 4
3: (SO::EVALUATE + 4 4)
3: EVALUATE returned 8
2: CALCULATE returned 8
2: (SO::CALCULATE (+ 4 3 2 5))
3: (SO::CALCULATE (4 3 2 5))
3: CALCULATE returned 4
3: (SO::CALCULATE (4 3 2 5))
3: CALCULATE returned 4
3: (SO::EVALUATE + 4 4)
3: EVALUATE returned 8
2: CALCULATE returned 8
2: (SO::EVALUATE * 8 8)
2: EVALUATE returned 64
1: CALCULATE returned 64
1: (SO::EVALUATE - 64 64)
1: EVALUATE returned 0
0: CALCULATE returned 0
0
That last 0 is the result. Of the numbers, only the first one is ever touched, and I guess you meant to use the others too.
It should be helpful to point out that the two calls to (calculate (cdr l)) inside of calculate will always produce the same result.
Side notes:
- use standard formatting (see e. g. http://www.gigamonkeys.com/book/syntax-and-semantics.html#formatting-lisp-code)
- use the apostrophe
', not the backtick. The latter has different uses. - understand the difference between symbols and strings
Ok, thanks for the tracking. I expect it to calculate the prefix notation arithmetic expression given in the list l. And I hoped that the list gets passed by reference and all the cdr's done firstly will be seen in the second call.