2cache ( ... key1 key2 assoc quot: ( ... key1 key2 -- ... value ) -- ... value )
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cache ( ... key assoc quot: ( ... key -- ... value ) -- ... value )

Vocabulary
assocs

Inputs

key1	a key
key2	a key
assoc	an assoc
quot	a quotation with stack effect ( ... key1 key2 -- ... value )

Outputs

value

a previously-retained or freshly-computed value

Word description
If a single key composed of the input keys is present in the assoc, outputs the associated value, otherwise calls the quotation to produce a value and stores the keys/value pair into the assoc. Returns the value stored in the assoc. Returns a value either looked up or newly stored in the assoc.

Side effects
Modifies assoc

Definition

USING: arrays kernel sequences.private ;

IN: assocs

: 2cache
    ( ... key1 key2 assoc quot: ( ... key1 key2 -- ... value ) -- ... value )
    [ 2array ] 2dip [ first2-unsafe ] prepose cache ; inline