Class: PluggableDictionary

• Inheritance
• Description
• Class protocol
  • instance creation
• Instance protocol
  • private
  • queries
• Examples

Inheritance:

   Object
   |
   +--Collection
      |
      +--Set
         |
         +--Dictionary
            |
            +--PluggableDictionary
               |
               +--Dolphin::PluggableLookupTable

Package:

stx:libbasic2

Category:

Collections-Unordered

Version:

rev: 1.10 date: 2023/05/12 09:03:32

user: cg

file: PluggableDictionary.st directory: libbasic2

module: stx stc-classLibrary: libbasic2

Description:

a dictionary where the hash- and compare functions can be provided externally.
Can be used eg. to implement dictionaries which ignore case differences,
or which map diareses to replacement sequences (as in german: Umlaut-u to ue).

copyright
COPYRIGHT (c) 2014 by Claus Gittinger
             All Rights Reserved

This software is furnished under a license and may be used
only in accordance with the terms of that license and with the
inclusion of the above copyright notice.   This software may not
be provided or otherwise made available to, or used by, any
other person.  No title to or ownership of the software is
hereby transferred.

Class protocol:

 hashWith: hashFunctionArg compareWith: compareFunctionArg

return a dictionary which hashes using the given hash function
and compare function (both are one-arg blocks)

Instance protocol:

 compareSame: element1 with: element2

compare two elements for being the same.
Here, return the value from compareFunction

 find: key ifAbsent: aBlock

Look for the key in the receiver. If it is found, return
the index of the association containing the key, otherwise
return the value of evaluating aBlock.
Redefined - since we inherit this code from Set-Dictionary
(one of the seldom cases, where I could make use of multiple inheritance
and inherit from IdentitySet ... sigh)

 findKeyOrNil: key

Look for the key in the receiver.
If it is found, return return the index of the first unused slot.
Grow the receiver, if key was not found, and no unused slots were present

 findKeyOrNilOrDeletedEntry: key

Look for the key in the receiver.
If it is found, return return the index of the first unused slot.
Grow the receiver, if key was not found, and no unused slots were present

 hashFor: aKey

return an initial index given a key.

 hashWith: hashFunctionArg compareWith: compareFunctionArg

specify how to hash and how to compare elements
(see example on the class side)

 occurrencesOf: anObject

count & return how often anObject is stored in the dictionary.
This counts values - not keys.
Redefined to use compareFunction, instead of the inherited equality compare.

Examples:

  |s|

  s := PluggableDictionary
      hashWith:[:k | k asLowercase hash] 
      compareWith:[:a :b | a notNil and:[b notNil and:[a asLowercase = b asLowercase]]].
  s at:'hello' put:123.
  s at:'world' put:222.
  s at:'abc' put:333.
  s at:'Hello'.
  s at:'heLLo'.
  s at:'ABC'.
  s at:'WORLD'.
  s size.
  s includesKey:'heLlo'.  
  s includesKey:'wOrLd'.  
  s includesKey:'wOrLds'.