My understanding of $validate() is, that this function suppresses only those characters, which are not allowed to be used within a filename or filepath.
The single apostroph and some sort of brackets are allowed characters to create a filename.
A function $num() is already covered in Mp3tag scripting language and would collide with your wish, because of different functionality.
Have you tried the function $replace()?
Example:
$replace('test'$char(39)'test',$char(39),$char(95))
$replace('test''''test',$char(39),)
$replace('test''''test','',)
$replace(test''test,'',_)
... will give the same result:
test_test
Example:
$replace('äöüÄÖÜß','ä','a','ö','o','ü','u','Ä','A','Ö','O','Ü','U','ß','ss')
$replace(äöüÄÖÜß,ä,a,ö,o,ü,u,Ä,A,Ö,O,Ü,U,ß,ss)
... will give the same result:
aouAOUss
Have you tried the function $regexp?
Example:
$regexp('test123öäütest','[^a-zA-Z0-9]',)
Result:
test123test
Example:
$regexp('test123öäütest','[^a-zA-Z]',)
Result:
testtest
Example:
$regexp('test123öäütest','[a-zA-Zöäü]',)
Result:
123
How to convert Unicode characters to ASCII/ANSI characters read there ....
Unicode to ASCII
[X] Regexp error
Change Bartók Béla to Bartok Bela (loose the special chars)
DD.20100321.1401.CET