7.3.2 Identifiers
[1] identifier = initial (subsequent* final)? | peculiar-identifier
[2] initial = letter | special-initial | added-name-character
[3] letter = a | b | c || z | A | B | C || Z
[4] special-initial = special | :
[5] special = ! | $ | % | & | * | / | < | = | > | ? | &tilde. | _ | ^
[6] subsequent = initial | digit | special-subsequent
[7] special-subsequent = . | + | -
[8] final = letter | special | added-name-character | digit | special-subsequent
[9] peculiar-identifier = + | - | ...
Most identifiers allowed by other programming languages are also acceptable in DSSSL. In addition to letters and digits, identifiers may contain the characters $%&*/:<=>?&tilde._^+-. and any characters declared as added-named-characters by the add-name-chars or char-repertoire element type forms. An identifier shall not begin with a character that can begin a number; however, +, -, and ... are identifiers. An identifier shall not end with : (unless the entire identifier is :).

NOTE 6

... are three period characters and not a single ellipsis character.