regExp method Null safety

AskValidator regExp(
  1. String regExp,
  2. {String? error}
)

Validates the input against a regular expression

ask('Variable Name:', validator: Ask.regExp(r'^[a-zA-Z_]+$'));

Implementation

static AskValidator regExp(String regExp, {String? error}) =>
    _AskRegExp(regExp, error: error);