4.4.17 satisfies [Type Specifier]

Compound Type Specifier Kind::

Predicating.

Compound Type Specifier Syntax::

(satisfies{predicate-name})

Compound Type Specifier Arguments::

predicate-name—a symbol.

Compound Type Specifier Description::

This denotes the set of all objects that satisfy the predicate predicate-name, which must be a symbol whose global function definition is a one-argument predicate. A name is required for predicate-name; lambda expressions are not allowed. For example, the type specifier (and integer (satisfies evenp)) denotes the set of all even integers. The form (typep x '(satisfies p)) is equivalent to (if (p x) t nil).

The argument is required. The symbol * can be the argument, but it denotes itself (the symbol *), and does not represent an unspecified value.

The symbol satisfies is not valid as a type specifier.