prev ( loc document quot: ( loc document -- loc ) -- loc )

Vocabulary

documents.elements.private

Inputs

loc	an object
document	an object
quot	a quotation with stack effect ( loc document -- loc )

Outputs

loc

an object

Definition

USING: combinators documents kernel math sequences ;

IN: documents.elements.private

: prev ( loc document quot: ( loc document -- loc ) -- loc )
    {
        { [ pick { 0 0 } = ] [ 2drop ] }
        {
            [ pick second zero? ]
            [ drop [ first 1 - ] dip line-end ]
        }
        [ call ]
    } cond ; inline