change-at ( ..a key assoc quot: ( ..a value -- ..b newvalue ) -- ..b )
Factor handbook » The language » Collections » Associative mapping operations » Storing keys and values in assocs

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Vocabulary
assocs

Inputs

key	an object
assoc	an assoc
quot	a quotation with stack effect ( ..a value -- ..b newvalue )

Outputs
None

Word description
Applies the quotation to the value associated with key, storing the new value back in the assoc.

Side effects
Modifies assoc

See also
?change-at, change-nth, change

Definition

USING: kernel ;

IN: assocs

: change-at
    ( ..a key assoc quot: ( ..a value -- ..b newvalue ) -- ..b )
    [ [ at ] dip call ] [ drop ] 3bi set-at ; inline