String Expressions

A string expression designates a string, that is, a sequence of characters. It has the following form:

<string-literal>

<identifier>

Here the identifier must be string-valued.

In the message clause of a rule, the operator + can be used to form a complex string expression:

<string-expression> + <string-expression>

The result of evaluation of a complex string expression is the result of concatenating the values of the string-expressions.

See Identifiers and Literals for information on string literals and identifiers.