IDs and Semantics

An identifier (ID) is a unique identifier.

IDs

IDs have the following restrictions.

• They must contain only upper and lower case letters, digits, and underscores.
• They must not start with a digit.
• They must be distinct from all keywords and other IDs in the same scope.
• They are case sensitive.

Semantics

Parameter identifier tags that indicate a usage class. The usage class is how this parameter will typically be used by the application (or compiler). They provide a mechanism for adding user-specific information to a parameter.

Semantic strings have the following restrictions.

• They must contain only upper and lower case letters, digits, and underscores.
• They must not start with a digit.
• They must be distinct from all keywords.
• They are case sensitive.