Delimiter is either a single special character or a sequence of two special characters as follows:
+ ^ == ! : )
- & >= && ; [
* < > || := |
/ <= <> . .. {
** = != , ( }
If delimiter consists of two characters, there must be no spaces between the characters.
All the delimiters have fixed meaning, which will be explained on discussion corresponding syntactic constructions, where the delimiters are used.