1.4 Identifiers

Identifiers denote programmer defined names for specific constants, types, variables, procedures and functions, units, and programs. All programmer defined names in the source code – excluding reserved words – are designated as identifiers.

Identifiers consist of between 1 and 127 significant characters (letters, digits and the underscore character), of which the first must be a letter (a–z or A–Z), or an underscore (_). The following diagram gives the basic syntax for identifiers.


           --x --- --|letter----
                     --x ---

Like Pascal reserved words, identifiers are case insensitive, that is, both




refer to the same procedure.

Remark As of version 2.5.1 it is possible to specify a reserved word as an identifier by prepending it with an ampersand (&). This means that the following is possible:

program testdo;  
procedure &do;  

The reserved word do is used as an identifier for the declaration as well as the invocation of the procedure do.