isLetter function

bool isLetter(
  1. String ch
)

Implementation

bool isLetter(String ch) {
  if (ch.isEmpty) {
    return false;
  }

  int rune = ch.codeUnitAt(0);
  return (rune >= 0x41 && rune <= 0x5A) || (rune >= 0x61 && rune <= 0x7A);
}