keep-under ( quot -- quot' )
Extra combinators

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Vocabulary
combinators.extras

Inputs

quot	a quotation

Outputs
None

Word description
Calls a quotation with a value on the stack, restoring the value below the outputs when the quotation returns.

Definition

USING: combinators.smart generalizations kernel math ;

IN: combinators.extras

MACRO: keep-under ( quot -- quot' )
    dup outputs 1 + [ [ keep 1 ] curry ] dip
    [ 0 -nrotated ] curry compose ;