/// Position::flip() flips position with the white and black sides reversed. This
/// is only useful for debugging e.g. for finding evaluation symmetry bugs.
-static char toggle_case(char c) {
- return char(islower(c) ? toupper(c) : tolower(c));
-}
-
void Position::flip() {
string f, token;
ss >> token; // Castling availability
f += token + " ";
- std::transform(f.begin(), f.end(), f.begin(), toggle_case);
+ std::transform(f.begin(), f.end(), f.begin(),
+ [](char c) { return char(islower(c) ? toupper(c) : tolower(c)); });
ss >> token; // En passant square
f += (token == "-" ? token : token.replace(1, 1, token[1] == '3' ? "6" : "3"));