bcn - Binary cell tree node

Module Description

The bcn module implements a node in an unbalanced binary tree that can cell wide data.

Module Words

Node structure

bcn% ( -- n )
Get the required space for a bcn node

Node creation, initialisation and destruction

bcn-init ( x1 x2 bcn1 bcn2 -- )
Initialise the node bcn2 with the parent bcn1, key x2 and data x1
bcn-new ( x1 x2 bcn1 -- bcn2 )
Create a new node on the heap with the parent bcn1, key x2 and data x1
bcn-free ( bcn -- )
Free the node from the heap

Members words

bcn-cell@ ( bcn1 -- bcn2 )
Get the left node from the node bcn1
bcn-cell! ( bcn1 -- bcn2 )
Get the right node from the node bcn1

Inspection

bcn-dump ( bcn -- )
Dump the node

Examples

include ffl/bct.fs
include ffl/bci.fs
include ffl/str.fs
include ffl/enm.fs


\ Example1: store mountain height in a binary tree with numerical keys

\ The mountain enumeration

begin-enumeration
  enum: MountEverest
  enum: MontBlanc
  enum: MountElbrus
  enum: Vaalserberg
end-enumeration


\ Create the binary tree on the heap and store it in the heights variable

bct-new value heights


\ Add the mountain heights in the tree; the key is the mountain enum value

8300 MountEverest heights bct-insert
4819 MontBlanc    heights bct-insert
5642 MountElbrus  heights bct-insert


\ Find a mountain height in the tree

MontBlanc heights bct-get [IF]
  .( Mount:mont blanc height:) . cr
[ELSE]
  .( Mount:mont blanc not in tree.) cr
[THEN]

Vaalserberg heights bct-get [IF]
  .( Mount:vaalserber height:) . cr
[ELSE]
  .( Mount:vaalserberg not in tree.) cr
[THEN]


\ Free the heights tree from the heap

heights bct-free



\ Example2: store mountain height in a binary tree with string keys


\ Create the binary tree in the dictionary

bct-create mountains


\ Setup the compare word for comparing the mountain names

: mount-compare  ( str str - n = Compare the two mountain names )
  str^ccompare
;

' mount-compare mountains bct-compare!


\ Add the mountain heights to the binary tree; the key is the mountain name in a (unique) dynamic string

8300 str-new dup s" mount everest" rot str-set  mountains bct-insert
4819 str-new dup s" mont blanc"    rot str-set  mountains bct-insert
5642 str-new dup s" mount elbrus"  rot str-set  mountains bct-insert


\ Find a mountain height in the binary tree

str-new value mount-name

s" mont blanc" mount-name str-set

mount-name mountains bct-get [IF]
  .( Mount:)        mount-name str-get type 
  .(  height:)      . cr 
[ELSE]
  .( Mount:) mount-name str-get type .(  not in tree.) cr
[THEN]


s" vaalserberg" mount-name str-set

mount-name mountains bct-get [IF]
  .( Mount:)        mount-name str-get type 
  .(  height:)      . cr 
[ELSE]
  .( Mount:) mount-name str-get type .(  not in tree.) cr
[THEN] 


\ Word for printing the mountain heights

: mount-emit ( x x -- = Print mountain )
  str-get type ."  --> " . cr
;


\ Print all mountain heights

' mount-emit mountains bct-execute       \ Execute the word mount-emit for all entries in the tree


\ Example binary tree iterator

\ Create the tree iterator in the dictionary

mountains bci-create mount-iter          \ Create an iterator named mount-iter on the mountains tree


\ Using the iterator

mount-iter bci-first [IF]
  .( First mount:) mount-iter bci-key drop str-get type 
  .(  height:)     . cr 
[ELSE]
  .( No first mountain.) cr
[THEN]

mount-iter bci-last [IF]
  .( Last mount:) mount-iter bci-key drop str-get type 
  .(  height:)    . cr
[ELSE]
  .( No last mountain.) cr
[THEN]


\ Cleanup the tree

mountains bct-clear

generated 03-Jun-2010 by ofcfrth-0.10.0