Regex not proceeded or followed by a -

[newbtophp]

~^(??<!\-)[a-z0-9\-]{2,}(?!\-)|(?<!\-)[a-z0-9\-]+(?!\-)\.(?<!\-)[a-z0-9\-]{2,}(?!\-))$~D

 

I have the above expression, which will match the specified characters (with the specified length) and optionally a fullstop followed by more specified characters (with the specified length).

 

Im trying to make it so it matches only if its not proceeded by a - and not followed by a - .

 

So example the following will match:

 

hey.phpfreaks

hey

yo-u.me

 

However the following will not match:

-hey

hey-

-hey-

you.-he

 

I've tried using (?<!\-) (not proceeded by -) and (?!\-) (not followed by -) but that doesn't seem to work? 

[newbtophp]

Anyone can help? I tried using [^\-]* but doesn't seem to make any effect?

[sasa]

~^[^-][a-z0-9\-]{1,}[^-](\.[^-][a-z0-9\-]{1,}[^-])?$~D