fulfill ( value promise -- )
Promises

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Vocabulary
concurrency.promises

Inputs

value	an object
promise	a promise

Outputs
None

Word description
Fulfills a promise by writing a value to it. Any threads waiting for the value are notified.

Errors
Throws an error if the promise has already been fulfilled.

Definition

USING: accessors concurrency.mailboxes kernel ;

IN: concurrency.promises

: fulfill ( value promise -- )
    dup promise-fulfilled?
    [ promise-already-fulfilled ] [ mailbox>> mailbox-put ] if ;