GBBopen 1.5 Reference -- llrb-tree-value

llrb-tree-value

llrb-tree-value key llrb-tree &optional default => value, present-p [Function]

Purpose
Return the value associated with a given key.

Setf syntax

(setf (llrb-tree-value key llrb-tree &optional default) value) => value

=> value, present-p

Package :gbbopen-tools

Module :gbbopen-tools

Arguments and values

key		An object
llrb-tree		An LLRB tree
default		An object (default is `nil`)
value		An object
present-p		A generalized boolean

Returns
Two values:

The value associated with the given key or default if no entry is associated with key
True, if an entry was found; nil if there is no such entry

Description
Setf may be used with llrb-tree-value to replace the value associated with the given key, or to add a new entry. When a llrb-tree-value form is used as a setf place, any default which is supplied is evaluated, but its value is ignored.

Example

  > (defparameter *tree* (make-llrb-tree #'compare&))
  *tree*
  > (llrb-tree-value 1 *tree*)
  nil
  > (setf (llrb-tree-value 1 *tree*) 'a)
  a
  > (llrb-tree-value 1 *tree*)
  a
  t
  >

The GBBopen Project

llrb-tree-value