BNF Syntax, Structure and Conventions : Symbol Types

Symbol Types

Terminal symbols are basic symbols which are not parsed further to derive their meaning. Non-terminal symbols are those which may be further broken down by parsing. Examples of terminal symbols may be integer numbers which are intrinsically recognized as a numeric value, or language keywords recognized by the system as representing some particular operation or function.

In BNF Syntax, Structure and Conventions terminal symbols that are written exactly as they appear (i.e., keywords of the SCL) are show in capital letters. Non-alphabetic characters not belonging to the BNF notation below, are also part of the syntax (e.g., ;). Non-terminal symbols are written in lowercase or mixed case letters. Non-terminal symbols which are self evident are not further broken down.