Terminals

The following names are used as terminals in the grammar. They denote classes of tokens, and are defined precisely in Section A.4.3.

Delim

A pathname delimiter. Either forward or backward slashes are allowed within pathnames, but not both.

Integer

An integer, expressed in either decimal, octal, or hexadecimal.

Id

An identifier. An identifier is any sequence of letters, digits, periods, and underscores that does not represent an integer. For example, foo and 36.foo are identifiers, but 36 and 0x36 are not.

Text

A text string. Texts are enclosed in double-quotes. They may contain escape sequences and spaces.

Comments and white space follow C++ conventions. A comment either begins with // and ends with the first subsequent newline, or begins with /* and ends with */ (the latter form does not nest). Of course, these delimiters are only recognized outside text literals. White space delimits tokens but is otherwise ignored (except that the Space character, the ASCII character represented by the decimal number 32, is significant within text literals). The grammar prohibits white space other than the Space character within text literals.

The names of the built-in functions begin with an underscore character, and the identifier consisting of a single period (i.e., ``.'') plays a special role in the Vesta SDL. It is therefore recommended that Vesta programs avoid defining identifiers of these forms.