“doc” (Col. : Science Sup 17x24) — 2007/7/19 — 18:18 — page 176 — #186
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• Techniques de programmation déclarative
functor
export
new:NewDict put:Put condGet:CondGet entries:Entries
define
fun {NewDict} leaf end
fun {Put Ds Key Value}
case Ds of leaf then tree(Key Value leaf leaf)
[] tree(K _ L R) andthen K==Key then
tree(K Value L R)
[] tree(K V L R) andthen K>Key then
tree(K V {Put L Key Value} R)
[] tree(K V L R) andthen K tree(K V L {Put R Key Value})
end
end
fun {CondGet Ds Key Default}
case Ds of leaf then Default
[] tree(K V _ _) andthen K==Key then V
[] tree(K _ L _) andthen K>Key then
{CondGet L Key Default}
[] tree(K _ _ R) andthen K {CondGet R Key Default}
end
end
fun {Entries Ds}
proc {EntriesD Ds S1 ?Sn}
case Ds of leaf then
S1=Sn
[] tree(K V L R) then S2 S3 in
{EntriesD L S1 S2}
S2=K#V|S3
{EntriesD R S3 Sn}
end
end
in {EntriesD Ds $ nil} end
end
Figure 3.18 Un dictionnaire en forme bibliothèque (fichier Dict.oz).