A version of Rubinius' CompactLookupTable for Slate

CompactLookupTable.st

define: #CompactMapping &parents: {Collection. Mapping} &slots: {
  #contents -> #{}
}.

m@(CompactMapping traits) new*
[| *rest |
  m new `>> [contents := rest. ]
].

m@(CompactMapping traits) size
[m contents size // 2].

m@(CompactMapping traits) capacity
[m size].

m@(CompactMapping traits) keysDo: block
[
  0 below: m contents size by: 2 do:
    [| :index | block apply*, (m contents at: index)].
].

m@(CompactMapping traits) valuesDo: block
[
  1 below: m contents size by: 2 do:
    [| :index | block apply*, (m contents at: index)].
].

m@(CompactMapping traits) at: key ifAbsent: block
[
  0 below: m contents size do:
    [| :index | (m contents at: index) = key ifTrue:
       [^ (m contents at: index + 1)]].
  block do
].

m@(CompactMapping traits) at: key put: obj
[
  0 below: m contents size do:
    [| :index | (m contents at: index) = key ifTrue:
       [^ (m contents at: index + 1 put: obj)]].
  0 below: m contents size do:
    [| :index | (m contents at: index) ifNil:
       [m contents at: index put: key.
        ^ (m contents at: index + 1 put: obj)]].
  error: 'This mapping cannot accept new key-value pairs.'
].

m@(Mapping traits) removeKey: key ifAbsent: block
[
  0 below: m contents size do:
    [| :index | (m contents at: index) = key ifTrue:
       [m contents at: index put: Nil. m contents at: index + 1 put: Nil]].
  block do
].

m@(Mapping traits) keyAtValue: obj ifAbsent: block
[
  1 below: m contents size by: 2 do:
    [| :index | (m contents at: index) = obj ifTrue:
       [^ (m contents at: index - 1)]].
  block do
].

m@(Mapping traits) keysAndValuesDo: block
[
  0 below: m contents size by: 2 do:
    [| :index | block apply*, (m contents at: index), (m contents at: index + 1)].
].

m@(Mapping traits) allSatisfy: block
[
  m valuesDo: [| :value | (block apply*, value) ifFalse: [^ False]].
  True
].