func numberOperator(left, right tree.Result, f *xpFilt, op string) error {
lt, lOK := left.(tree.IsNum)
rt, rOK := right.(tree.IsNum)
if !lOK || !rOK {
return fmt.Errorf("Cannot convert data type to number")
}
ln, rn := lt.Num(), rt.Num()
switch op {
case "*":
f.ctx = ln * rn
case "div":
if rn != 0 {
f.ctx = ln / rn
} else {
if ln == 0 {
f.ctx = tree.Num(math.NaN())
} else {
if math.Signbit(float64(ln)) == math.Signbit(float64(rn)) {
f.ctx = tree.Num(math.Inf(1))
} else {
f.ctx = tree.Num(math.Inf(-1))
}
}
}
case "mod":
f.ctx = tree.Num(int(ln) % int(rn))
case "+":
f.ctx = ln + rn
case "-":
f.ctx = ln - rn
case "=":
f.ctx = tree.Bool(ln == rn)
case "!=":
f.ctx = tree.Bool(ln != rn)
case "<":
f.ctx = tree.Bool(ln < rn)
case "<=":
f.ctx = tree.Bool(ln <= rn)
case ">":
f.ctx = tree.Bool(ln > rn)
case ">=":
f.ctx = tree.Bool(ln >= rn)
}
return nil
}
func count(c tree.Ctx, args ...tree.Result) (tree.Result, error) {
n, ok := args[0].(tree.NodeSet)
if !ok {
return nil, fmt.Errorf("Cannot convert object to a node-set")
}
return tree.Num(len(n)), nil
}
func ceiling(c tree.Ctx, args ...tree.Result) (tree.Result, error) {
n, ok := args[0].(tree.IsNum)
if !ok {
return nil, fmt.Errorf("Cannot convert object to a number")
}
return tree.Num(math.Ceil(float64(n.Num()))), nil
}
func stringLength(c tree.Ctx, args ...tree.Result) (tree.Result, error) {
var str string
if len(args) == 1 {
str = args[0].String()
} else {
str = c.NodeSet.String()
}
return tree.Num(len(str)), nil
}
func round(c tree.Ctx, args ...tree.Result) (tree.Result, error) {
isn, ok := args[0].(tree.IsNum)
if !ok {
return nil, fmt.Errorf("Cannot convert object to a number")
}
n := isn.Num()
if math.IsNaN(float64(n)) || math.IsInf(float64(n), 0) {
return n, nil
}
if n < -0.5 {
n = tree.Num(int(n - 0.5))
} else if n > 0.5 {
n = tree.Num(int(n + 0.5))
} else {
n = 0
}
return n, nil
}
func sum(c tree.Ctx, args ...tree.Result) (tree.Result, error) {
n, ok := args[0].(tree.NodeSet)
if !ok {
return nil, fmt.Errorf("Cannot convert object to a node-set")
}
ret := 0.0
for _, i := range n {
ret += float64(tree.GetNodeNum(i))
}
return tree.Num(ret), nil
}
func substring(c tree.Ctx, args ...tree.Result) (tree.Result, error) {
str := args[0].String()
bNum, bErr := round(c, args[1])
if bErr != nil {
return nil, bErr
}
b := bNum.(tree.Num).Num()
if float64(b-1) >= float64(len(str)) || math.IsNaN(float64(b)) {
return tree.String(""), nil
}
if len(args) == 2 {
if b <= 1 {
b = 1
}
return tree.String(str[int(b)-1:]), nil
}
eNum, eErr := round(c, args[2])
if eErr != nil {
return nil, eErr
}
e := eNum.(tree.Num).Num()
if e <= 0 || math.IsNaN(float64(e)) || (math.IsInf(float64(b), 0) && math.IsInf(float64(e), 0)) {
return tree.String(""), nil
}
if b <= 1 {
e = b + e - 1
b = 1
}
if float64(b+e-1) >= float64(len(str)) {
e = tree.Num(len(str)) - b + 1
}
return tree.String(str[int(b)-1 : int(b+e)-1]), nil
}
func last(c tree.Ctx, args ...tree.Result) (tree.Result, error) {
return tree.Num(c.Size), nil
}
func position(c tree.Ctx, args ...tree.Result) (tree.Result, error) {
return tree.Num(c.Pos), nil
}
func xfNumLit(f *xpFilt, val string) {
num, _ := strconv.ParseFloat(val, 64)
f.ctx = tree.Num(num)
}