isLetter static method

bool isLetter(
  1. String char
)

Implementation

static bool isLetter(String char) {
  int symbol = char.codeUnitAt(0);

  if (symbol >= 'a'.codeUnitAt(0) && symbol <= 'z'.codeUnitAt(0)) return true;
  if (symbol >= 'A'.codeUnitAt(0) && symbol <= 'Z'.codeUnitAt(0)) return true;
  if (symbol >= 'а'.codeUnitAt(0) && symbol <= 'я'.codeUnitAt(0)) return true;
  if (symbol >= 'А'.codeUnitAt(0) && symbol <= 'Я'.codeUnitAt(0)) return true;

  return false;
}