keep ( ..a x quot: ( ..a x -- ..b ) -- ..b x )
Factor handbook » The language » Combinators » Dataflow combinators » Preserving combinators

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Vocabulary
kernel

Inputs

x	an object
quot	a quotation with stack effect ( ..a x -- ..b )

Outputs

x

an object

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

Examples

USING: arrays kernel prettyprint ; 2 "greetings" [ <array> ] keep 2array .
{ { "greetings" "greetings" } "greetings" }

Definition

IN: kernel

: keep ( ..a x quot: ( ..a x -- ..b ) -- ..b x )
    over [ call ] dip ; inline