markdown.utils.pas ``` function IsValidEmail(const S : String) : boolean; type TState = (sNeutral,sUser,sHost,sDomain); var lState : TState; c : char; begin Result:=False; if s.CountChar('@') <> 1 then Exit; lState:=sNeutral; for c in s do Case lState of sNeutral: if c='@' then Exit else lState:=sUser; sUser: if c='@' then lState:=sHost; else if c='.' then lState:=sDomain else if c='+' then Exit; end; Result:=lState=sDomain; end; ``` 1. func detects empty username and returns False. but it don't detect empty hostname nor empty domain. these return True: ``` IsValidEmail('a@.a') IsValidEmail('a@a.') ``` 2. domain-name must have at least 2 wordchars. currently, I repeat, minimal count is 0. 3. need to detect that hostname/domain have only wordchars, not any chars. 4. for username - some punctuations are allowed too. this must be checked. supported char-set for username can be asked from good AI. note: pls don't use RegEx for this func if you work on it, it will by slower by 1-2 orders.