CL Enumerations: Standard Generic Function CURRENT
 

Generic function CURRENT

Package:

CL.EXTENSIONS.ENUMERATIONS

Syntax:

  current enumeration &optional errorp default
  => object
  

Arguments and Values:

enumeration---an enumeration instance

errorp---a generalized boolean (default T)

default---an object (default NIL)

object---an object

Description:

Each ENUMERATION instance maintains a reference to its "current" element (if within "range"). Given an ENUMERATION instance enumeration, the generic function CURRENT returns the object in such reference.

If errorp is non-NIL, a call to CURRENT signals a possibly continuable error if no element of the enumeration is available. Specialized methods of CURRENT signal an error of type NO-SUCH-ELEMENT.

If errorp is NIL, and there is no "current" element in enumeration, then default is returned.

Affected By:

The internal state of enumeration.

Exceptional Situations:

CURRENT may signal a continuable error or NO-SUCH-ELEMENT. See above for an explanation.

See Also:

ENUMERATION class, BOUNDED-ENUMERATION, NUMBER-ENUMERATION, BI-DIRECTIONAL-ENUMERATION, SEQUENCE-ENUMERATION, LIST-ENUMERATION, ARRAY-ENUMERATION, VECTOR-ENUMERATION, STRING-ENUMERATION, HASH-TABLE-ENUMERATION, NO-SUCH-ELEMENT.

Notes:

None.