3.3.1.1 Evaluating Literal Data

When a literal data expression is evaluated, the value of the expression is simply the value that the expression describes. The evaluation of a literal data expression has no side effects.

So, for example,

• the value of the expression "abc" is the string value "abc"
• the value of the expression 3+4i is the complex number 3 + 4i
• the value of the expression #(1 2 3) is a three-element vector containing the numeric values 1, 2 and 3.

For any data type which can be expressed literally like this, the syntax of the literal data expression for that data type — in other words, what you need to write in your code to indicate a literal value of that type — is known as the data type’s read syntax. This manual specifies the read syntax for each such data type in the section that describes that data type.

Some data types do not have a read syntax. Procedures, for example, cannot be expressed as literal data; they must be created using a lambda expression (see Creating a Procedure) or implicitly using the shorthand form of define (see Lambda Alternatives).