(rule) ( head body pos -- )

Vocabulary

logic.private

Inputs

head	an object
body	an object
pos	an object

Outputs

None

Definition

USING: accessors arrays combinators kernel sequences vectors ;

IN: logic.private

:: (rule) ( head body pos -- )
    reset-anonymouse-var-no head replace-'__' def>goal
    :> head-goal body replace-'__' normalize split-body pos
    at-the-beginning = [ reverse ] when dup empty? [
        head-goal swap 2array 1vector head-goal pred>>
        [ pos at-the-end = [ swap ] when append! ] change-defs
        drop
    ] [
        f :> negation?! [
            [
                {
                    { ~quotation~ ~quotation~ }
                    { ~quotation~ ~quotation~ }
                    { ~quotation~ ~quotation~ }
                    { ~quotation~ ~quotation~ }
                    { ~quotation~ ~quotation~ }
                    [ drop dummy-item f negation?! ]
                } cond
            ] map dummy-item swap remove :> body-goals
            V{ { head-goal body-goals } } head-goal pred>>
            [ pos at-the-end = [ swap ] when append! ]
            change-defs drop
        ] each
    ] if ;