func processRequest(request *http.Request) ([3]float64, string, bool) {
var floats [3]float64
count := 0
for index, key := range []string{"a", "b", "c"} {
if slice, found := request.Form[key]; found && len(slice) > 0 {
if slice[0] != "" {
x, err := strconv.ParseFloat(slice[0], 64)
if err != nil {
return floats, "'" + slice[0] + "' is invalid", false
}
floats[index] = x
} else { // as a courtesy to users treat blanks as 0
request.Form[key][0] = "0"
floats[index] = 0
}
count++
}
}
if count != 3 { // the first time the form is empty;
return floats, "", false // this isn't an error but there's
} // nothing to calculate
if numbers.EqualFloat(floats[0], 0, -1) {
return floats, "the x² factor may not be 0", false
}
return floats, "", true
}
func formatComplex(x complex128) string {
if numbers.EqualFloat(imag(x), 0, -1) {
return fmt.Sprintf("%.*f", decimals, real(x))
}
return fmt.Sprintf("%.*f", decimals, x)
}