3.6.6 Evaluation examples

The symbol ⇒ used in program examples can be read “evaluates to”. For example:

(* 5 8)
⇒ 40

means that the expression (* 5 8) evaluates to the object 40. Or, more precisely: the expression given by the sequence of characters (* 5 8) evaluates, in an environment that imports the relevant library, to an object that may be represented externally by the sequence of characters 40.

The ⇒ symbol is also used when the evaluation of an expression causes a violation. For example:

(integer->char #xD800)
⇒ &assertion exception

means that the evaluation of the expression (integer->char #xD800) must raise an exception with condition type &assertion.

Moreover, the ⇒ symbol is also used to explicitly say that the value of an expression in unspecified. For example:

(eqv? "" "")
⇒ unspecified

Mostly, examples merely illustrate the behavior specified in the entry. In some cases, however, they disambiguate otherwise ambiguous specifications and are thus normative. Note that, in some cases, specifically in the case of inexact number objects, the return value is only specified conditionally or approximately. For example:

(atan -inf.0)
⇒ -1.5707963267948965 ; approximately