GBBopen 1.5 Reference -- in-eset

in-eset

in-eset

item eset => item-or-nil, present-p

[Function]

Purpose
Determine if item is in eset using eq as the comparison function.

Package :gbbopen-tools

Module :gbbopen-tools

Arguments and values

item		An object
eset		An ESET
item-or-nil		An object or `nil`
present-p		A generalized boolean

Returns
Two values:

item, if item is a member of eset; otherwise nil
True, if an entry was found; nil if there is no such entry

See also
    add-to-eset
    make-eset
    memq
    delete-from-eset

Examples

  > (defparameter *eset* (make-eset))
  *eset
  > (in-eset 'x *eset*)
  nil
  nil
  > (add-to-eset 'x *eset*)
  x
  > (in-eset 'x *eset*)
  x
  t
  > (in-eset nil *eset*)
  nil
  nil
  > (add-to-eset nil *eset*)
  nil
  > (in-eset nil *eset*)
  nil
  t
  >

The GBBopen Project

in-eset