Each market has its own IdeaTokenNameVerifier which is a small contract performing basic checks on a token name. These name verifiers are used by the IdeaTokenFactory when a new token is listed. For example on the Twitter market the TwitterHandleNameVerifier is used to verify the token name is a valid Twitter handle (@ followed by 1-15 letters or numbers including "_". All lower-case) :
contract TwitterHandleNameVerifier is IIdeaTokenNameVerifier {/*** Verifies whether a string matches the required format** @param name The input string (Twitter handle)** @return Bool; True=matches, False=does not match*/function verifyTokenName(string calldata name) external pure override returns (bool) {bytes memory b = bytes(name);if(b.length < 2 || b.length > 16) {return false;}​if(b[0] != 0x40) { // @return false;}​for(uint i = 1; i < b.length; i++) {bytes1 char = b[i];if (!(char >= 0x30 && char <= 0x39) && //9-0!(char >= 0x61 && char <= 0x7A) && //a-z!(char == 0x5F)) { //_return false;}}​return true;}}
If the token name verification is unsuccessful the IdeaTokenFactory will revert on addToken.