Free Pascal allows all characters, digits and some special ASCII symbols in a Pascal source file.
Recognised symbols
The following characters have a special meaning:
+ - * / = < > [ ] . , ( ) : ^ @ { } $ #
and the following character pairs too:
<= >= := += -= *= /= (* *) (. .) //When used in a range specifier, the character pair (. is equivalent to the left square bracket [. Likewise, the character pair .) is equivalent to the right square bracket ].
When used for comment delimiters, the character pair (* is equivalent to the left brace { and the character pair *) is equivalent to the right brace }.
These character pairs retain their normal meaning in string expressions.