value-at* ( value assoc -- key/f ? )
Factor handbook » The language » Collections » Associative mapping operations » Transposed assoc operations

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Vocabulary
assocs

Inputs

value	an object
assoc	an assoc

Outputs

key/f	the key associated to the value or f
?	a boolean

Word description
Looks up the key associated with a value. The boolean flag can decide between the case of a missing key, and a key of f.

Definition

IN: assocs

GENERIC: value-at* ( value assoc -- key/f ? )

Methods

USING: assocs kernel ;

M: assoc value-at* swap [ = nip ] curry assoc-find nip ;


USING: accessors assocs biassocs ;

M: biassoc value-at* to>> at* ; inline