validateAppName function
Implementation
void validateAppName(String name) {
final RegExp pattern = RegExp(r'^[A-Za-z_][A-Za-z0-9_]*$');
if (!pattern.hasMatch(name)) {
throw ArgumentError(
"Invalid app name '$name': must be a valid identifier.",
);
}
if (name == 'user') {
throw ArgumentError(
"App name cannot be 'user'; reserved for end-user input.",
);
}
}