(*) now evaluates to 1 instead of 0

I have no idea if this matters or if it's in the spec or anything like
that.

acc.go

@@ -16,7 +16,7 @@ type accumulator struct {
 
 func (a *accumulator) total(vals []interface{}) (interface{}, error) {
 	if vals == nil || len(vals) == 0 {
-		return int64(0), nil
+		return a.acc, nil
 	}
 
 	switch v := vals[0].(type) {

proc.go

@@ -63,6 +63,8 @@ func multiplication(vals []interface{}) (interface{}, error) {
 		intFn: func(left, right int64) (int64, error) {
 			return left * right, nil
 		},
+		acc:  1,
+		accf: 1.0,
 	}
 	return a.total(vals)
 }