define-generic ( word combination effect -- )
Factor handbook » The language » Objects » Generic words and methods » Generic word introspection

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Vocabulary
generic

Inputs

word	a word
combination	a method combination
effect	an effect

Outputs
None

Word description
Defines a generic word. A method combination is an object which responds to the perform-combination generic word.

Generic word contract
The method combination quotation is called each time the generic word has to be updated (for example, when a method is added), and thus must be side-effect free.

See also
generic, define-simple-generic, GENERIC:, GENERIC#:, MATH:, HOOK:

Definition

USING: combinators kernel words ;

IN: generic

: define-generic ( word combination effect -- )
    [ [ check-combination-effect ] keep set-stack-effect ] [
        drop 2dup [ "combination" word-prop ] dip =
        [ 2drop ] [
            {
                [ drop reset-generic ]
                [ "combination" set-word-prop ]
                [ drop H{ } clone "methods" set-word-prop ]
                [ define-default-method ]
            } 2cleave
        ] if
    ] [ 2drop remake-generic ] 3tri ;